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Renewable Energy Questions/Discussion => Automation, Controls, Inverters, MPPT, etc => Topic started by: welshman on November 11, 2016, 04:19:30 am

Title: Just bought a powerjack 15000, modding.
Post by: welshman on November 11, 2016, 04:19:30 am
Hi, i have been reading this forum for a few days and there is some excellent information on here.

i just wanted to ask a few questions about my pj 15000 230/48v.

just got it out of the box and all i have done so far is inspect inside the unit for quality and possible faults and connected the supplied mains power lead to the unit and powered on. however nothing happens on the unit. is this normal?


a bit of background to the setup of the situation.

completely off grid (power utility want £30k to install, not happening)

22kva diesel single phase generator 80amp output.

2kw wind turbine, with 2kw controller /charger feeding into the batteries.

2 x 1200w 48v water heating elements on relays connected to voltage sensors that will divert the load of the wind turbine charge away from the batteries when full.

16 x 130 ah sealed lead acid batteries. 4 banks of 48v. giving 520ah.

voltage detector on supply from generator, when supply fails, via relay the inverter is switched off and back on immediately. what kind of delays would be needed here?

there is a voltage detector on battery bank, when voltage falls below threshold for several seconds the generator is remotely started and stopped again when the voltage is above a threshold for several seconds.

and my plan is to add more wind turbines as time goes on reducing the run time of the generator.

i want to do a few modifications to the powerjack

firstly i intend to rehouse the unit into a wall mount cabinet seperating the mosfet board/heatsink/control board to the toroids and have permanently on, 48v fans keeping both sides of the unit cool. hopefully this will give it all a better run time and keep things extra cool to give it a long life.

secondly i want to fit RCD 'fuses' to the high voltage input and output of the inverter does that mean i need to tie the earth to the neutral?

what about the earthing of the generator? it has a metal rod in the ground near it and is earthed to it. should i connect the battery bank negative to the same earth and neutral line of the output of the inverter?

can we modify the software of the inverter to take care of the on off blowing fet's problem when grid power fails?

what fet's would be a better replacement for the originals to help prevent problems? i was intending to buy plenty of spare parts now before something fails.

thanks in advance, i will post some picture of the internals of the powerjack.
Title: Re: Just bought a powerjack 15000, modding.
Post by: welshman on November 11, 2016, 05:41:38 am
Some photo's
Title: Re: Just bought a powerjack 15000, modding.
Post by: welshman on November 11, 2016, 05:45:24 am
Some more photo's
Title: Re: Just bought a powerjack 15000, modding.
Post by: welshman on November 11, 2016, 07:02:57 am
The mosfets on the boards are HY3810's and there are 24 of them in banks of 6.

what would be a replacement equivalent or better to these?
Title: Re: Just bought a powerjack 15000, modding.
Post by: welshman on November 12, 2016, 04:53:24 pm
Hi, i have been reading this forum for a few days and there is some excellent information on here.

i just wanted to ask a few questions about my pj 15000 230/48v.

just got it out of the box and all i have done so far is inspect inside the unit for quality and possible faults and connected the supplied mains power lead to the unit and powered on. however nothing happens on the unit. is this normal?


a bit of background to the setup of the situation.

completely off grid (power utility want £30k to install, not happening)

22kva diesel single phase generator 80amp output.

2kw wind turbine, with 2kw controller /charger feeding into the batteries.

2 x 1200w 48v water heating elements on relays connected to voltage sensors that will divert the load of the wind turbine charge away from the batteries when full.

16 x 130 ah sealed lead acid batteries. 4 banks of 48v. giving 520ah.

voltage detector on supply from generator, when supply fails, via relay the inverter is switched off and back on immediately. what kind of delays would be needed here?

there is a voltage detector on battery bank, when voltage falls below threshold for several seconds the generator is remotely started and stopped again when the voltage is above a threshold for several seconds.

and my plan is to add more wind turbines as time goes on reducing the run time of the generator.

i want to do a few modifications to the powerjack

firstly i intend to rehouse the unit into a wall mount cabinet seperating the mosfet board/heatsink/control board to the toroids and have permanently on, 48v fans keeping both sides of the unit cool. hopefully this will give it all a better run time and keep things extra cool to give it a long life.

secondly i want to fit RCD 'fuses' to the high voltage input and output of the inverter does that mean i need to tie the earth to the neutral?

what about the earthing of the generator? it has a metal rod in the ground near it and is earthed to it. should i connect the battery bank negative to the same earth and neutral line of the output of the inverter?


can we modify the software of the inverter to take care of the on off blowing fet's problem when grid power fails?

what fet's would be a better replacement for the originals to help prevent problems? i was intending to buy plenty of spare parts now before something fails.

thanks in advance, i will post some picture of the internals of the powerjack.
Title: Re: Just bought a powerjack 15000, modding.
Post by: Pete on November 12, 2016, 07:30:42 pm
Hello Welshman, a few points.
Looking at your photos it appears that the inverter Earth goes to the case of the inverter from the earth connections. To get RCD circuit breakers to work you will have to connect the Neutral to the Earth. I can't see any point in connecting the input of the inverter to an RCD as they are designed to protect people from electric shock not machines. Putting an RCD on the output is really all you need to do. Usually the Neutral and Earth are connected together at the switchboard ( in Australia) . Depending on what sort of switchboard you are using there may already be an RCD there to protect the power and lighting circuits of you house.
You say that you have plugged the AC ( high voltage) inputs into the inverter and nothing happens, I would think that the inverter will need to be connected to the batteries first before it will power up.
The AC input is there to power the inverter as a battery charger or alternately to act as a change over to switch from the mains or generator through to the house supply.
Title: Re: Just bought a powerjack 15000, modding.
Post by: welshman on November 14, 2016, 04:08:11 pm
Hello Welshman, a few points.
Looking at your photos it appears that the inverter Earth goes to the case of the inverter from the earth connections. To get RCD circuit breakers to work you will have to connect the Neutral to the Earth. I can't see any point in connecting the input of the inverter to an RCD as they are designed to protect people from electric shock not machines. Putting an RCD on the output is really all you need to do. Usually the Neutral and Earth are connected together at the switchboard ( in Australia) . Depending on what sort of switchboard you are using there may already be an RCD there to protect the power and lighting circuits of you house.
You say that you have plugged the AC ( high voltage) inputs into the inverter and nothing happens, I would think that the inverter will need to be connected to the batteries first before it will power up.
The AC input is there to power the inverter as a battery charger or alternately to act as a change over to switch from the mains or generator through to the house supply.

thanks for the input pete. i have decided to leave the earth and neutral seperate and fit an RCBO to the output. They compare the difference between positive and neutral and they detect leak to earth, so i reckon these would provide better detection/protection.

Title: Re: Just bought a powerjack 15000, modding.
Post by: Pete on November 15, 2016, 01:36:37 am
Hi again Welshman, I would try the RCBO out by using an RCD tester or just use a test lamp connected from the Active to the Earth connection.
If you put a 240 volt lamp between the Active and Earth and the RCBO does not trip then you will have to connect the Neutral to the Earth.
What an RCD or an RCBO does is to measure leakage current, It measures the current in the Active line and the Neutral line. They must be equal as the Neutral is the return circuit. If there is any difference it means that current is going to earth somewhere, hopefully not through you. And the breaker trips.
Here our Neutrals are always earthed, that way there is only one live conductor to worry about and if one house in the street has an earth fault it does not cause a voltage rise on all the houses after it.
Kind of complicated but we call it a MEN, (multiple Earthed Neutral system).
So try it out first,
From my tests I have always had to connect the Neutral to the Earth to get them to work.
Cheerio
Pete
Title: Re: Just bought a powerjack 15000, modding.
Post by: welshman on November 15, 2016, 04:38:32 am
Hi again Welshman, I would try the RCBO out by using an RCD tester or just use a test lamp connected from the Active to the Earth connection.
If you put a 240 volt lamp between the Active and Earth and the RCBO does not trip then you will have to connect the Neutral to the Earth.
What an RCD or an RCBO does is to measure leakage current, It measures the current in the Active line and the Neutral line. They must be equal as the Neutral is the return circuit. If there is any difference it means that current is going to earth somewhere, hopefully not through you. And the breaker trips.
Here our Neutrals are always earthed, that way there is only one live conductor to worry about and if one house in the street has an earth fault it does not cause a voltage rise on all the houses after it.
Kind of complicated but we call it a MEN, (multiple Earthed Neutral system).
So try it out first,
From my tests I have always had to connect the Neutral to the Earth to get them to work.
Cheerio
Pete

thanks again pete, i did a bit more "educating" on the matter, taking consensus from various places . from what i understand if we bond the earth to the netural, then if there is a short between positive ac and ground then the battery terminals will become energised with the output ac voltage and an RCD type device in this situation MUST always be fitted if you dont want to die by touching your battery terminals(or whatever else the ac is doing to the batteries).

so if we bond one of ac outputs (the one the inverter treats as neutral) to earth and inturn make that into a neutral, the inverter no longer has two live/hot/positive wires as it has as standard and such halving the chances of touching a live wire. but in doing so we must fit an rcd to shutdown the inverter output because if the live wire gets shorted to earth it will delivery the ac current back down to the battery terminals.

one thing i am not certain about is, since im going to make on of the wires a neutral by bonding it to earth on the inverter output, should i also bond earth to neutral in the generator too if it is not aready done? im assuming it must be as there are rcd's in the generator itself. the generator is a new hyundai dhy22ksem.

everything will have a common earth rod as to not induce differentials between earth points.

 



Title: Re: Just bought a powerjack 15000, modding.
Post by: frackers on November 15, 2016, 04:59:49 am
Note that the bonding of Neutral to Earth must be on the inverter transformer side of the RCB. That way any leakage bypasses the RCB which causes the unbalance and hence trips it out.

Not sure where this idea of mains on battery terminals comes from. There is no mains connection to the battery,  there is a great lump of transformer in the way that isolates the mains from the DC side. That's the whole point of having a transformer!! Shorting live mains to earth in fact will connect it to neutral due to the bonding which just shorts out the output of the transformer - no effect (apart from the current draw) on the DC side.
Title: Re: Just bought a powerjack 15000, modding.
Post by: welshman on November 15, 2016, 05:05:04 am
this is the simplest circuit i could come up with to detect when the mains power, in this case a generator, is switched off or fails so the inverter can be powered down immediately for the delay of C1 to prevent mutiple phases in the toroids going down to the fets and killing them.

i also put in a relay for fault detection as some people has considered that, but it would depend on what the inverter does as even a flash of the fault light would reset it. a simple cap and resistor in line would allow it to wait for more than a flash.
Title: Re: Just bought a powerjack 15000, modding.
Post by: welshman on November 15, 2016, 05:06:24 am
Note that the bonding of Neutral to Earth must be on the inverter transformer side of the RCB. That way any leakage bypasses the RCB which causes the unbalance and hence trips it out.

Not sure where this idea of mains on battery terminals comes from. There is no mains connection to the battery,  there is a great lump of transformer in the way that isolates the mains from the DC side. That's the whole point of having a transformer!! Shorting live mains to earth in fact will connect it to neutral due to the bonding which just shorts out the output of the transformer - no effect (apart from the current draw) on the DC side.

because the case of the inverter is earth and bonded to the neutral, if the positive touches the earth it will send down ac via the dc negative which is also earth by casing.

edit - thanks for the input on where to place the earth neutral bond. after checking the gen wiring out better, ill know if there is also a bond of it's earth to neutral. im assuming it does since it uses rcd's. what would having bond the both side of the link do? - while in bypass mode it will have a earth to neg bond in the generator then an rcd then to the inverter input via the control board then via the output of the inverter then tied negative to earth again into an rcbo then feeding the consumer unit.
Title: Re: Just bought a powerjack 15000, modding.
Post by: welshman on November 15, 2016, 05:32:33 am
in the case of the pj control board the earth neutral tie point would be here? between yellow and black?

edit - OR should i disconnect the earth (yellow) from the control board and connect it onto the negative terminal (black) then connect the other end of the earth wire to the ground via rod? why would that earth point on the control board be there and is there resistance free continuinty between dc negative and earth (yellow) terminal ? ill test.
Title: Re: Just bought a powerjack 15000, modding.
Post by: welshman on November 15, 2016, 12:54:25 pm
checked the generator (single phase) wiring, it has earth and neutral bonded at the alternator. next going to check the earth on control board and dc negative to see if there is continuity, if so i plan to disconnect the earth from the inverter mainboard and tie the earth to the black inverter ac output and make that neutral.
Title: Re: Just bought a powerjack 15000, modding.
Post by: Pete on November 15, 2016, 02:55:50 pm
Hi Welshman, the easiest way to tie the Earth to the Neutral is at your switchboard on the house. There is usually a neutral bar and an earth bar, a short wire is run between the two. RCD's or RCBO's are usually mounted on the switchboard for ease of use.
If you want to do it at the inverter, just leave all the inverter internal connections as they are, and connect the neutral to the earth at the output terminal block. Just a short loop of wire will do.
I always connect the case of the inverter to earth as well. A wire directly from the case to the earth terminal on the switchboard or to the earth rod.
cheerio
Pete
Title: Re: Just bought a powerjack 15000, modding.
Post by: welshman on November 16, 2016, 06:47:29 am
Hi Welshman, the easiest way to tie the Earth to the Neutral is at your switchboard on the house. There is usually a neutral bar and an earth bar, a short wire is run between the two. RCD's or RCBO's are usually mounted on the switchboard for ease of use.
If you want to do it at the inverter, just leave all the inverter internal connections as they are, and connect the neutral to the earth at the output terminal block. Just a short loop of wire will do.
I always connect the case of the inverter to earth as well. A wire directly from the case to the earth terminal on the switchboard or to the earth rod.
cheerio
Pete

thanks for the reply pete.

I have tested the continuity of the earth on the control board to any other point , ac/dc and there is no continuity. removing the control board from the heat sinks I had a look at the traces on the pcb's and found the earth only joins to anything via these capacitors.

if I join the neutral and earth it is essentially shorting both the caps. is that going to be a problem?



Title: Re: Just bought a powerjack 15000, modding.
Post by: welshman on November 16, 2016, 07:27:03 am
some images of the resister values

Title: Re: Just bought a powerjack 15000, modding.
Post by: welshman on November 16, 2016, 03:13:17 pm
it's new housing and fans have arrived. 600x600x300 ip65 enclosure and a set of 240v fans on a rack. next job cut out the enclosure.

Title: Re: Just bought a powerjack 15000, modding.
Post by: welshman on November 16, 2016, 03:41:43 pm
one thing i have noticed, although the build quality is ok to good. there is metal filings loose everywhere in the casing, there is also a lot of left over flux all over the boards and you can see which modifications are made by someone else as they are not using enough heat to solder and its causing the solder to ball instead of sink into the metal. based on this anyone buying one of these should thoroughly wash the boards and inside of the metal casing as some of those bits of metal were up to 3-4mm long and freely floating about in the case could one day or day 1 cause a short or worse.

it looks like they add a capacitor and a resistor to the fet boards and a couple of resistors to the control board, you can clearly see the difference in soldering.
Title: Re: Just bought a powerjack 15000, modding.
Post by: welshman on November 17, 2016, 10:44:01 am
first test fit for marking out holes etc, plenty of airflow is the plan.
Title: Re: Just bought a powerjack 15000, modding.
Post by: Pete on November 17, 2016, 03:17:08 pm
Hello Welshman, first the bonding of the neutral to earth is done on the output side of the transformer. That is the 230 volt side. You can make the connection by connecting the neutral and earth at the RCBO. Just bring out the active, neutral and earth wires to the RCBO, connect the neutral and active as usual to the breaker, then on the output side of the breaker connect the earth and neutral.
The earth continues on to all the earth connections in the house or wherever you are supplying power to.
The Active and neutral likewise.
I would not change any connections inside the  inverter.
I have two PowerStar W7 inverters they are both connected to an MEN system in my shed and house. I have just connected the earth bar to the neutral bar in my swithboards , all works well.
You need to remember that the control board in the inverter is on the low voltage side of the transformer, so are the Mosfets. The inverter circuits basically turn the DC from the batteries into an AC waveform to drive the primary (low voltage side) of the inverter. The secondary (high voltage) side is connected to the loads.
As Frackers pointed out a fault on the output side of the inverter should not be able to feed back through the transformer to the battery side.
Keep all Modifications such as connecting the earth and neutral and connecting the RCBO to the high voltage AC side of the inverter.  Either to the Output terminals or on your house switchboard.
Title: Re: Just bought a powerjack 15000, modding.
Post by: Pete on November 17, 2016, 03:36:10 pm
Welshman I put a diagram on a post to anther member about a powerjack, if you look at the posts about the 8000watt powerjack you will see the diagram at the end of the posts.
http://www.anotherpower.com/board/index.php/topic,1091.30.html
hope this helps
Pete
Title: Re: Just bought a powerjack 15000, modding.
Post by: sunnypower46 on November 17, 2016, 07:38:45 pm
Was wondering if anyone has tried improving airflow for the toroid(s) by removing the top/bottom hold down discs, turning the toroid on its side and literally blowing air through and around the thing?

Seems inefficient to bottle up all the heat in the core when a different mounting arrangement could be tried.  I figure PowerJack chose that mounting arrangement as a mechanically secure shipping method.  Not worrying about that once it's arrived, maybe there's a better way.  From what I've read on this site, toroid heat is what is holding back the continuous power output of these units.

At some point I'd like to try that with my PJ 8000 LF SP, unless someone can convince me that's a really stupid idea and a waste of my time.  Any takers?



Title: Re: Just bought a powerjack 15000, modding.
Post by: welshman on November 18, 2016, 05:44:06 am
Was wondering if anyone has tried improving airflow for the toroid(s) by removing the top/bottom hold down discs, turning the toroid on its side and literally blowing air through and around the thing?

Seems inefficient to bottle up all the heat in the core when a different mounting arrangement could be tried.  I figure PowerJack chose that mounting arrangement as a mechanically secure shipping method.  Not worrying about that once it's arrived, maybe there's a better way.  From what I've read on this site, toroid heat is what is holding back the continuous power output of these units.

At some point I'd like to try that with my PJ 8000 LF SP, unless someone can convince me that's a really stupid idea and a waste of my time.  Any takers?

ill look into mounting them from the ceiling of the unit with something that can clamp around it and through the hole. metal strap with some rubber lining, a juiblee clamp perhaps, it might make them vibrate a little? and what happens when you place a looped wire or metal bar around the toroid how does this effect the currents?
Title: Re: Just bought a powerjack 15000, modding.
Post by: welshman on November 18, 2016, 05:49:17 am
I wonder why transformers dont incorporate any cooling factors into their design, is it simply if it's too hot it's not big enough mentality? (or easier just to house them in oil?) what about a ring style heatsink to go around the edge of the toroid providing cooling fins for it? would that be a problem with the magnetic currents?
Title: Re: Just bought a powerjack 15000, modding.
Post by: welshman on November 18, 2016, 06:33:43 am
Was wondering if anyone has tried improving airflow for the toroid(s) by removing the top/bottom hold down discs, turning the toroid on its side and literally blowing air through and around the thing?

Seems inefficient to bottle up all the heat in the core when a different mounting arrangement could be tried.  I figure PowerJack chose that mounting arrangement as a mechanically secure shipping method.  Not worrying about that once it's arrived, maybe there's a better way.  From what I've read on this site, toroid heat is what is holding back the continuous power output of these units.

At some point I'd like to try that with my PJ 8000 LF SP, unless someone can convince me that's a really stupid idea and a waste of my time.  Any takers?

since you have a pj 8000 it would be interesting to see what the difference of the adjust resistor on the controll board. mine has a smd with "1000" on it which translates into 100 ohms.

Title: Re: Just bought a powerjack 15000, modding.
Post by: Pete on November 18, 2016, 02:32:16 pm
Welshman, I would be very careful with the idea of hanging the torroids from a metal bracket. You may be just adding a secondary winding of one turn . In other words a giant high current secondary closed loop. The Eddy currents flowing in the bracket would be enormous.
As to trying to get more power from the inverter by cooling the transformer, I am not sure why you need more than 15kw. If you do then you would need to add another set of driver transistors and also another transformer in parallel.
Probably easier and cheaper to buy another inverter and split your loads across the two inverters.
Just wire the buildings up with multiple power circuits and split the loads evenly.
It would be cheaper than blowing up a perfectly good inverter trying to squeeze a few more watts out of it. And also add a level of reliability, that is if one inverter died and needed repairs at least you would have the other one.
Generally the main limiting factor on inverters is the battery bank size and capacity. Plus whatever charging equipment you have.
Remember that you have to put in more than you take out. The old no free lunches part.
Best to keep it as simple as possible, that is my way of looking at renewable energy.
Title: Re: Just bought a powerjack 15000, modding.
Post by: welshman on November 18, 2016, 03:08:30 pm
Welshman, I would be very careful with the idea of hanging the torroids from a metal bracket. You may be just adding a secondary winding of one turn . In other words a giant high current secondary closed loop. The Eddy currents flowing in the bracket would be enormous.
As to trying to get more power from the inverter by cooling the transformer, I am not sure why you need more than 15kw. If you do then you would need to add another set of driver transistors and also another transformer in parallel.
Probably easier and cheaper to buy another inverter and split your loads across the two inverters.
Just wire the buildings up with multiple power circuits and split the loads evenly.
It would be cheaper than blowing up a perfectly good inverter trying to squeeze a few more watts out of it. And also add a level of reliability, that is if one inverter died and needed repairs at least you would have the other one.
Generally the main limiting factor on inverters is the battery bank size and capacity. Plus whatever charging equipment you have.
Remember that you have to put in more than you take out. The old no free lunches part.
Best to keep it as simple as possible, that is my way of looking at renewable energy.

that's the kind of thing i was thinking, so one loop of metal would be like shorting the transformer. best it be a nylon cargo tie strap or something similar.

the idea here is not going for big power, just aiming to get a decent amount for continuous time greater than the original spec of the powerjack as it is in its tiny box, which will probably mean over riding the limits of current detection.

edit - i want it to do 230 v @ 40 amps for an hour, which would equate to  9.2kw output and 238amps at dc 48v with an 80% efficiency in the system.

my batteries are 520 a/h in total, if i can get 40% out of that i will be coming close to the goal, if i can't ill double the battery bank to give extra time.

the system will be slow charged at low output of the inverter by wind turbine and at high current when over 150a is taken from battery or when a critical point is reached of low voltage of the battery bank then the generator kicks in and does a full charge.


that might just be pipe dreams in practice. but as close to that
Title: Re: Just bought a powerjack 15000, modding.
Post by: sunnypower46 on November 18, 2016, 09:05:22 pm
Welshman, I agree with Pete re using a metal strap.  Not a good idea.  Need to use something non-metallic.

Your 9.2KW continuous goal may be tough without special cooling.  The continuous power output of PJs is known to be highly overrated.  The toroid heats up quickly and the attached thermistor will shut the unit down.  If you can open up the toroids and improve the airflow, you may have shot at 9.2KW.  Otherwise, 35-40% of PJs stated power output is what you should expect (continuous). 

At 3KW, my PJ 8000 (24v) toroid is very hot to the touch.  Granted, you're running 48v so current should be half what runs through my single toroid, and heat will be further divided by your two toroids.  So, maybe you've got a reasonable shot at it.

A note about the batteries.  My PJ holds output AC voltage quite good.  But, as the battery voltage drops, DC current must increase to deliver the wattage.  As the amps go up, battery internal resistance increases and the system works harder to meet your needs.  And the battery voltage drops faster and faster toward auto shutdown.

I'll try and find the "adjust resistor" on mine this weekend.  I'm not sure our control boards are exactly the same.
Title: Re: Just bought a powerjack 15000, modding.
Post by: ClockmanFrance on November 19, 2016, 02:49:47 am
Sunnypower46.

Cooling toroid, OzInverter.

As you can see from the photo with this normal 6kW 30kg toroid, 48vdc to 230vac, the Primary turns are 50mm/2 about 12mm in diameter.

This then gives a good 10mm airflow around the secondary and through the centre hole, without having to drill or alter the holding disk and clamp rubbers.

I trust this helps.

And..... 




Title: Re: Just bought a powerjack 15000, modding.
Post by: sunnypower46 on November 19, 2016, 10:00:47 am
>ClockmanFrance:  Nice!  The photo and video were very enlightening.

Reading between the lines (er: pixels), it appears the extremely heavy gauge primary wire opens up an airway at the top and bottom of the toroid.  So, I expect a non-metallic spacer of sorts would achieve the same effect.  Directing airflow around and through the toroid with strategically placed deflectors would be worth trying.  That's seems easy enough to try when I can find some extra time.
Title: Re: Just bought a powerjack 15000, modding.
Post by: welshman on November 19, 2016, 01:00:16 pm
having some billet aluminium milled into bracket/busbar to mount the heatsink parallel with the board. this will allow me to connect the feed to the toroids direclty to the busbar and use thermal compound on the heatsink backface, which i know will make a significant difference in cooling alone, coupled with the change in angle of the heatsink with air being blown directly down onto them should keep them nice and cool.

also in process of stitching some thick seatbelt type material used for cargo straps in a loop around the toroids for mounting them, or rather hanging, from the ceiling as inspired by sunnypower46.

also c101 copper busbar ordered, thankfully got it at trade price through local fabricator. inch and qtr by qtr , 6 metres of.

i found this useful for bar sizing based on current

https://www.copper.org/applications/electrical/busbar/busbar_ampacities.html

and this useful for wire sizing.

http://www.engineeringtoolbox.com/wire-gauges-d_419.html

i got a piece of id 37mm tube turned down on the outside to slide into a scaffold tube to mount the istabreeze 2kw wind turbine on.

besides that had a tinker with some of the voltage sensors and relay timers, all seems to be straight forward.

waiting on a couple of bits and pieces but i can start work on the sensing circuits and gen control stuff.




Title: Re: Just bought a powerjack 15000, modding.
Post by: welshman on November 19, 2016, 01:54:19 pm
does anyone object to setting up a bank of batteries like this on the left instead of right?

it should provide the ability for slow charging cells to be not stressed or be an impedence by providing another path for the other cells/battery in series with said cell to carry their current.

it should also provide better equalisation and faster charging.

Title: Re: Just bought a powerjack 15000, modding.
Post by: Pete on November 19, 2016, 03:25:50 pm
Hi Welshman I am not a battery expert but the idea you have of paralleling up each 12 volt section seems like it would work. The main thing that I could see as a problem with it, is if one battery or cell dies or goes short circuit then all the preceding batteries will drain into it. You could end up with 4 times the short circuit current or alternately all the battery strings drained flat at once.
That one may be worth looking into a bit more, it could create problems when the batteries get older.
Pete
Title: Re: Just bought a powerjack 15000, modding.
Post by: welshman on November 19, 2016, 04:07:16 pm
Hi Welshman I am not a battery expert but the idea you have of paralleling up each 12 volt section seems like it would work. The main thing that I could see as a problem with it, is if one battery or cell dies or goes short circuit then all the preceding batteries will drain into it. You could end up with 4 times the short circuit current or alternately all the battery strings drained flat at once.
That one may be worth looking into a bit more, it could create problems when the batteries get older.
Pete

Thanks for the input, there seems to be plenty to consider.

This unit is now modified to switch off and on for a split second when generator power is lossed to try to soften the chances of the mosfets being blown when it reverses the direction of flow when at zero crossing on the waveform.

What do you think of placing an ac motor run cap across / inline of the ac output of the inverter, could i theoretically achieve the ability to maintain power during that split second reset?

something like this perhaps? http://www.ebay.co.uk/itm/1pc-CBB65A-1-450V-100UF-Air-conditioning-startup-capacitor-125-50mm-new-DIY-250g-/291551824164?hash=item43e1d7c924:g:4mMAAOSw3ydV4l4n

edit - could a large cap be used to filter the ac from the toroids so it doesnt blow the fet's in the first place?
Title: Re: Just bought a powerjack 15000, modding.
Post by: sunnypower46 on November 19, 2016, 06:41:23 pm
Followup:  My adjust resistor is labeled "1500".

Regarding your battery bank:  I have three series strings of two each 12volt.  The 24 volt output of each string goes to PJ via separate cables.  So, they parallel up at the PJ input.  In each series string I have a 100-0-100 shunt style analog ammeter to show the charge and discharge into each string.  Now, you would expect the strings to share the current equally, but they typically do not.  This gives me something of an early warning as to battery health.  It also gives me a reason to swap batteries around within the bank.

You could do this easiest with the right side configuration and also embrace Pete's observation.
Title: Re: Just bought a powerjack 15000, modding.
Post by: rossw on November 19, 2016, 06:55:16 pm
Welshman, I agree with Pete re using a metal strap.  Not a good idea.  Need to use something non-metallic.

Not sure I completely agree. I think metal will be fine, as long as it doesn't form a complete loop. If the attachment points at either end are insulated, the loop won't form a shorted turn.
Title: Re: Just bought a powerjack 15000, modding.
Post by: welshman on November 20, 2016, 04:27:50 am
Hi Welshman I am not a battery expert but the idea you have of paralleling up each 12 volt section seems like it would work. The main thing that I could see as a problem with it, is if one battery or cell dies or goes short circuit then all the preceding batteries will drain into it. You could end up with 4 times the short circuit current or alternately all the battery strings drained flat at once.
That one may be worth looking into a bit more, it could create problems when the batteries get older.
Pete

Thanks for the input, there seems to be plenty to consider.

This unit is now modified to switch off and on for a split second when generator power is lossed to try to soften the chances of the mosfets being blown when it reverses the direction of flow when at zero crossing on the waveform.

What do you think of placing an ac motor run cap across / inline of the ac output of the inverter, could i theoretically achieve the ability to maintain power during that split second reset?

something like this perhaps? http://www.ebay.co.uk/itm/1pc-CBB65A-1-450V-100UF-Air-conditioning-startup-capacitor-125-50mm-new-DIY-250g-/291551824164?hash=item43e1d7c924:g:4mMAAOSw3ydV4l4n

edit - could a large cap be used to filter the ac from the toroids so it doesnt blow the fet's in the first place?

after a bit of thought, turns out i will get 10ms max by using an ac cap this way and drawback would be the cost of constantly charging it, but dont put a cap on the output of a modified wave only full wave.

to save battery power it could be diconnected out of the circuit after generator is off.
Title: Re: Just bought a powerjack 15000, modding.
Post by: welshman on November 20, 2016, 04:31:17 am
Followup:  My adjust resistor is labeled "1500".

Regarding your battery bank:  I have three series strings of two each 12volt.  The 24 volt output of each string goes to PJ via separate cables.  So, they parallel up at the PJ input.  In each series string I have a 100-0-100 shunt style analog ammeter to show the charge and discharge into each string.  Now, you would expect the strings to share the current equally, but they typically do not.  This gives me something of an early warning as to battery health.  It also gives me a reason to swap batteries around within the bank.

You could do this easiest with the right side configuration and also embrace Pete's observation.

thanks for the resistor value.. 1500, that's 150 ohms.

150 ohn for 8000 PJ
100 ohm for 15000 PJ
50 ohm for 30000 PJ??
Title: Re: Just bought a powerjack 15000, modding.
Post by: welshman on November 20, 2016, 04:35:39 am
Welshman, I agree with Pete re using a metal strap.  Not a good idea.  Need to use something non-metallic.

Not sure I completely agree. I think metal will be fine, as long as it doesn't form a complete loop. If the attachment points at either end are insulated, the loop won't form a shorted turn.

that's puts the simple method of a jubilee clip and some rubber out of the question. would have been able to get that tight to reduce vibration damage.

i've settled for some straps and silicone to reduce friction from vibration.
Title: Re: Just bought a powerjack 15000, modding.
Post by: welshman on December 01, 2016, 01:29:51 pm
Update on progress.

Title: Re: Just bought a powerjack 15000, modding.
Post by: oztules on December 01, 2016, 03:16:07 pm
Looks like someone is having fun :)

........oztules
Title: Re: Just bought a powerjack 15000, modding.
Post by: welshman on December 02, 2016, 03:48:01 am
Looks like someone is having fun :)

........oztules

Thanks. It's been interesting and quite fun. I would like to take the opportunity to say that the information you have given in your forum posts has been invaluable in this project.
Title: Re: Just bought a powerjack 15000, modding.
Post by: Pete on December 02, 2016, 02:38:31 pm
Hello Welshman, on the busbars, make sure that the batteries are protected from objects being able to be dropped on them. I have had a battery explode in my face many years ago, not what anyone wants.
I have used two methods of insulating bus bars, the traditional method is to use heatshrink and just cut enough away for good connections to be made.
A much cheaper option is to slide pieces of poly pipe over the bar as insulation. I have used poly pipe as hot water pipe insulation too, it works great and is much cheaper than lagged pipe or heatshrink.
Just a thought to keep in mind, you have a capacity to supply very large fault currents if a spanner is dropped.
Cheerio
Pete
Title: Re: Just bought a powerjack 15000, modding.
Post by: welshman on December 03, 2016, 01:21:34 pm
Hello Welshman, on the busbars, make sure that the batteries are protected from objects being able to be dropped on them. I have had a battery explode in my face many years ago, not what anyone wants.
I have used two methods of insulating bus bars, the traditional method is to use heatshrink and just cut enough away for good connections to be made.
A much cheaper option is to slide pieces of poly pipe over the bar as insulation. I have used poly pipe as hot water pipe insulation too, it works great and is much cheaper than lagged pipe or heatshrink.
Just a thought to keep in mind, you have a capacity to supply very large fault currents if a spanner is dropped.
Cheerio
Pete

Thanks Pete, don't I know it! Had an incident yesterday where I was lining up the bars to final connect. One of the busbars went to fall and i reached to grab it to stop it falling on the rest of the bars, at that point i realised (due to current flow through arms)  i was holding 48v + in the left hand and - in the right hand, instantly the copper bar became magnetised and pulled itself out of my hand. The shock was interesting and despite me wearing rubber gloves. The bar proceded to short out and it burnt through one of the loose 8mm bolts I'm using as busbar inter-connects. I will definitely be insulating the entire exposed bar as a safety precaution!!

48 v @ 3200 amps is a hell of a lot of power. i've had my fair share of various voltage dc/ac shocks and the thing i notive about dc shocks is there is no warning like with 240v ac, you tend to feel the vibration a split second before the shock and know to let go. DC different thing entirely.

Title: Re: Just bought a powerjack 15000, modding.
Post by: Pete on December 04, 2016, 02:22:57 pm
Hi Welshman, sorry to hear you had to learn the hard way. That could have been very very nasty. My father in law many years ago, used to work on submarines, he told me a story of one of the electricians being killed. What happened was he was crawling across the top of the batteries doing maintenance, a shifting spanner fell out of his pocket and shorted across one of the cells. The current vaporised the spanner killing him in the explosion.
In the case that happened to me, I was foolishly testing a battery charger that supposedly had reverse connection protection. Only I did not take it apart to see that someone had bypassed the relay that afforded that protection. I had replaced the transformer and was testing it. The last test I did was to check if the reverse polarity protection worked.
Well as soon as I put the clip onto the battery terminal, a massive spark ignited the gas in the battery that I had just been charging.
The top blew off the battery into my face, with lots of battery acid. There was a massive white flash ( not the appearance of an angel but close) and the loudest bang. My ears rang for 15 minutes after.
Fortunately I found a tap and washed my face, all without being able to open my eyes.
I have never trusted battery reverse polarity protection since, and am extremely careful with busbars and connections.
I am glad to hear that you survived to tell your story.
Cheerio
Pete
Title: Re: Just bought a powerjack 15000, modding.
Post by: welshman on December 06, 2016, 10:55:17 am
almost there now.

information/explanation and better images will be uploaded soon.
Title: Re: Just bought a powerjack 15000, modding.
Post by: welshman on December 06, 2016, 10:59:46 am
also received a spare set of these just incase.

control board is still on it's way

Title: Re: Just bought a powerjack 15000, modding.
Post by: welshman on December 08, 2016, 04:06:15 am
Hi Welshman, sorry to hear you had to learn the hard way. That could have been very very nasty. My father in law many years ago, used to work on submarines, he told me a story of one of the electricians being killed. What happened was he was crawling across the top of the batteries doing maintenance, a shifting spanner fell out of his pocket and shorted across one of the cells. The current vaporised the spanner killing him in the explosion.
In the case that happened to me, I was foolishly testing a battery charger that supposedly had reverse connection protection. Only I did not take it apart to see that someone had bypassed the relay that afforded that protection. I had replaced the transformer and was testing it. The last test I did was to check if the reverse polarity protection worked.
Well as soon as I put the clip onto the battery terminal, a massive spark ignited the gas in the battery that I had just been charging.
The top blew off the battery into my face, with lots of battery acid. There was a massive white flash ( not the appearance of an angel but close) and the loudest bang. My ears rang for 15 minutes after.
Fortunately I found a tap and washed my face, all without being able to open my eyes.
I have never trusted battery reverse polarity protection since, and am extremely careful with busbars and connections.
I am glad to hear that you survived to tell your story.
Cheerio
Pete

thanks Pete, it's all part of the experience, who doesn't enjoy a good shock? back when i was a kid, messing about electrolysis and with making browns gas i got an idea of what kind of a bang hydrogen does and even small bubbles of the stuff makes a very loud bang. i can't imagine what a whole batteries worth of gas going off sounds like. with regards to finding a tap blind.. had to do that with break fluid in the face, that's no where near as bad as acid though.

im a little dissapointed that i left a few cosmetic marks in the bus bar where it was arching, a few little blobs of molten metal landed on one of the batteries but nothing was melted through anywhere. my policy now is to always make the bridge in the middle of the battery pack last.

Title: Re: Just bought a powerjack 15000, modding.
Post by: welshman on December 08, 2016, 12:10:34 pm
Modified Power board.
Title: Re: Just bought a powerjack 15000, modding.
Post by: welshman on December 10, 2016, 12:25:50 pm
Fired it up today, first test. Working Good. However the DROK DC-DC Buck Converter 48V to 12V blew it self up. Still trying to figure out why, so I ordered a 220v ac to 12dc 5 amp transformer instead to power the 12v stuff.

Gave it about an hours test giving out a nice 231v ac @ 48v dc. uses 1.2 amp dc @ idle and 2.2 amp dc with fans going.

voltage remained at 48.8v during entire test.
Title: Re: Just bought a powerjack 15000, modding.
Post by: Pete on December 10, 2016, 02:24:59 pm
Hi Welshman, looks good, seems a bit like re inventing the wheel though. I can't help but wonder what sort of load you want to run from it that would require you to do so much work on a working inverter.
What you have done looks great, I am just curious as to what you intend to run with it that needs that much power.
Also here is a question, I know that many of us do stuff like mountain climbers, Just because we love tinkering. But was the extra cost worth it in the end.
Would it have been cheaper to have split your power circuits and to have bought two inverters, one for each circuit.
In the end it doesn't matter that much, I just find using a small inverter for small loads and a big inverter for big loads uses less standby power and adds in some insurance for the time when the electronics turn to smoke.
In Tasmania our power suppliers found that out when they sold our electricity, in the form of running the dams dry ( we mostly have hydro power here). Along came a drought, then our extension lead linking us to the rest of Australia blew up, and presto, Oh we have a problem Huston.
Fortunately for our Hydro company and the Government we had very heavy rains in winter that just, and only just managed to save their backsides.
The cable took 6 months to repair.
Sometimes, as in the case of your buck converter I think it is best to keep things simple. Transformers are great, proven reliable and pretty easy to diagnose when things go pear shaped.
Anyway, keep on telling us how it goes.
Interested to know how much more power you can get out of it, compared to the standard unit.
Cheerio
Pete
Title: Re: Just bought a powerjack 15000, modding.
Post by: welshman on December 14, 2016, 01:36:28 pm
Update.

Been running the unit for a few days now. Testing various loads, charging the batteries via generator and wind turbine.

Even let it line transfer from charge to inverter mode and vice versa without powering down and with a 3kw load (have spares ready). When transferng from charge to inverter the lights running off it do a single split second flicker.

High surge loads like motors have no problem, for example the chop saw spins right up no delay or lights going out.

Something I have noticed the inverter seems to have a soft start as in it ramps up the voltage when switching it on. The control board i have is marked revision 3.6A and I've tried asking the suppliers for version changes information but to no avail. I also see the layout of the control board is significantly different to all others i have seen and even has resistors missing where there would normally be a resistor that you could change voltages with.

Also turns out i wired up the buck converter in reverse. out/in. Which is why it blew. Which means i was getting 48v on the 12v rail. What a schoolboy error that was. New one arrived, decided to stick with buck converter and not use 240v transformer as i need 12v rail with power while the inverter and generator are off.

I'm getting 80 AH over a 12 hr period on the wind turbine. With 25mph winds. Still waiting for stronger winds, typically it's been quite calm lately. With that wind speed it covers the idle and lighting household power use and puts a bit into the batteries too.

Title: Re: Just bought a powerjack 15000, modding.
Post by: welshman on December 20, 2016, 03:40:35 pm
I found the relay operating the restart of the system on gen power loss didn't work out as expected. Switch too fast and the inverter doesn't fire up correctly, too slow and everthing loses power. The inverter switches on it's own between charging and inverting in less than 7ms.

So what i have decided to do is this. Since I have full set of mosfets and a complete spare control board of same revision, which are only 100 dollars inc delivery, I'm going to let it switch back and forth on its own from charging and inverting and vice versa and see how long it lasts.

I've also decided to leave neutral floating and not connected to earth. In my mind if between part of the circuit board where the powejack has  the "neutral" path and the appliance is damaged in someway where it is now an open circtui and it is bonded to earth then the current will be sent down the earth wire. If this path happens to be more conductive at the appliance to ground than all the way back to the grounding rod, there could be a situation where there is a high voltage on the negative/neutral and anyone touching an appliance metal casing in this situation could receive a shock.

Contrary to popular belief, electricity takes all paths back to its source, not just the path of least resistance.

It may well be fine bridging earth to neutral in the consumer unit/main panel on mains where it's unlike that the neutral will break to the grid. But when relying on a circuit board made in china to a questionable quality, I'm not going to take the risk of bridging earth to neutral, I'm far safer not doing so and using a RCBO with less then 30ma trip, which monitors earth leak and neutral / hot sync.

The generator in using has its own earthing rod. It also has its neutral bonded to earth. The inverter and the entire sites wiring are on a seperate earth rod to the generator.

I've already watched it switch back and forth numerous times daily at various loads and battery states since i first fired it up.

It also makes a nice background heater, slightly raising the temp of the shed it is in keeping it all dry in there.

I have a device on the front panel, that monitors the voltage. When the voltage of the battery bank drops below 50v for 10 seconds it fires up the generator for an hour using a programmable time delay relay. So far this seems to be working. Seems to be putting in more than it takes out and avoids cycling the batteries. Im charging the batteries at 60.2v and the inverter starts off by putting in 50-60 amps charge and drops down to about 5 amps at about an hour of charge this way. The only downside is high loads for more than 10 seconds that drop the voltage below 50v but would otherwise recover to over 50v start the generator.

I've charged the batteries for hours on end using the desulfation option. It bubbles the batteries away nicely and doesn't seem to be any fluid loss at all, the viewing window on the batteries shows they are all full of fluid and the built in hydrometer shows a healthy green on all 16.

The wind turbine is behaving nicely. So far I've only seen it input 700 watts max and the wind speed has been quite low lately, not had above 25 mph gusts, but expecting some the next few days.. let's see if it hits 2kw at all, or if it fries itself.

What i have noticed is that the wind turbine does very little in the way of charging batteries. What it does seem to do is reduce the load taken off the batties by the inverter.

So far so good.


Title: Re: Just bought a powerjack 15000, modding.
Post by: welshman on December 20, 2016, 04:12:36 pm
Next step is to make everything a bit more intelligent. Something to monitor and control the batteries and charging better, I have plenty of experience with atmel at90 series so might make it out of that. but 48v down to 5 is a bit low resolution tbh, it needs some thinking.

Also i need to figure out a way of comparing the voltages of the batteries without sharing a commong ground.

The middle two columsn show a lower voltage than the outer than the outer two columns of the bank. Once the batteries are full they are within 0.05 of a volt of each other.

I could use a comparitor to detect when the voltage of the 4 columns of  batties connected in parallel is within a specfic range and then consider them charged and turn off the generator instead of running for an hour.

However i need to measure the voltage at 4 points on the bank without sharing a common ground and thus shorting between columns. This is fine using a a multimeter, but when using comparitors or for example the at90 mcus i'ts a bit harder to do.

Perhaps i will have to use optocouplers with a pwn signal.

Any idea's anyone?
Title: Re: Just bought a powerjack 15000, modding.
Post by: frackers on December 20, 2016, 05:27:55 pm
It may well be fine bridging earth to neutral in the consumer unit/main panel on mains where it's unlike that the neutral will break to the grid. But when relying on a circuit board made in china to a questionable quality, I'm not going to take the risk of bridging earth to neutral, I'm far safer not doing so and using a RCBO with less then 30ma trip, which monitors earth leak and neutral / hot sync.

I'm not sure from this that you understand how the RCB works. It compares neutral and live current and if they are different then it trips. The ONLY way they can be different is if the current somehow takes a different path back to the power source that bypasses the RCB.

For protect against a live voltage to earth shock, there must be a complete circuit to cause that unbalance, that is why neutral is bonded to earth before the RCB to make that circuit of source_live -> RCB -> distribution -> human_body -> kitchen_floor -> earth -> source_neutral. Note how the current it only passing through the RCB one way in this fault condition, causes the unbalance and trips out.

Here in NZ, that bonding is in the meter cabinet before the switchboard. In the UK it is at the local substation (which can allow the neutral line to float a few volts above ground). What happens in the US I've no idea as they have the most bazaar centre tapped 2 phase supply imaginable!!

Title: Re: Just bought a powerjack 15000, modding.
Post by: welshman on December 20, 2016, 07:57:19 pm
It may well be fine bridging earth to neutral in the consumer unit/main panel on mains where it's unlike that the neutral will break to the grid. But when relying on a circuit board made in china to a questionable quality, I'm not going to take the risk of bridging earth to neutral, I'm far safer not doing so and using a RCBO with less then 30ma trip, which monitors earth leak and neutral / hot sync.

I'm not sure from this that you understand how the RCB works. It compares neutral and live current and if they are different then it trips. The ONLY way they can be different is if the current somehow takes a different path back to the power source that bypasses the RCB.

For protect against a live voltage to earth shock, there must be a complete circuit to cause that unbalance, that is why neutral is bonded to earth before the RCB to make that circuit of source_live -> RCB -> distribution -> human_body -> kitchen_floor -> earth -> source_neutral. Note how the current it only passing through the RCB one way in this fault condition, causes the unbalance and trips out.

Here in NZ, that bonding is in the meter cabinet before the switchboard. In the UK it is at the local substation (which can allow the neutral line to float a few volts above ground). What happens in the US I've no idea as they have the most bazaar centre tapped 2 phase supply imaginable!!

While knowing you are probably right..

I don't get the practicality of it. The return path is ground. If there is no return path there is no shock or danger to protect against. If someone touches only the live wire and is grounded then there is current travelling across the live wire in the rcbo and not the "negative" wire. Thus there is a difference and the rcd should trip. If they touch only the live wire and are not grounded there is no risk of shock anyway. The same applies to the negative wire.


I've seen many people say the RCD won't trip or doesn't trip. I've seen equally as many people say it will trip.

The only way of getting a shock is by touching both the live and neutral at the same time.. which an RCD won't protect against anyway. in a neutral earth bonded system you could touch the live and earth at the same time to get the same result so in this respect it's actually worse.

Also if we removed the earth altogether from the system and isolated the inverter so it wasn't earthed either and throwing away the rcd, that would ironically be the safest option. Birds don't get electrocuted sitting on the live wire as in this sitaution we have an isolation transformer we shouldnt get a shock either.

The only way something could go wrong is if another appliance shorted "neutral" to the same physical ground or casing you are in contact with and also touching the live wire.

As far as i can tell the only reason the RCBO wont trip is because youre not getting a shock.

I'm going to test it all tomorrow.

I have a gut feeling the entire electrics industry grounds neutral for voltage stability and pretends in some far fetched situation it provides safety.

I know exactly what will happen. Ill bond the earth to the "neutral" and create a neutral and the next day the fets will be toast lmao.
Title: Re: Just bought a powerjack 15000, modding.
Post by: welshman on December 21, 2016, 02:20:22 pm
Did some multimeter tests today.

Live to "Neutral" 230v AC
Live to Earth (not bonded to battery negative and not bonded to "neutral") 234v AC
"Neutral" to earth 4v AC

No continuity between "neutral" and battery negative and no continuity between battery negative and ground and no continuity between neutral and ground.

And just for fun Live to me isolated off ground 124 v AC. Live to various other locations such as the floor walls and screws in the walls gave a variance of up to 120v. Neutral to me and various locations was no higher than 12v AC.

Tomorrow try to trip the RCBO if that's even possible.
Title: Re: Just bought a powerjack 15000, modding.
Post by: welshman on December 21, 2016, 02:25:26 pm
Does anyone know what usually happens to these inverters if the live shorts to earth or if the live shorts to neutral? do they blow anything or are they tolerant to this? Do these inverters fault where the battery could be shorted and would burning out the fets be the end of the short?
Title: Re: Just bought a powerjack 15000, modding.
Post by: Wolvenar on December 25, 2016, 12:06:37 am
I am not sure about *those* but any I have had will trip a fuse/breaker on the HV side.
Doing this often though might get hard on the fets?
I cant say how yours will act though.
Title: Re: Just bought a powerjack 15000, modding.
Post by: Fionn on January 12, 2017, 03:25:52 am
1. As has already been stated, your RCD won't work without the neutral to earth connection, you should reinstate it, ideally at your main distribution board has has been suggested.

2. Your idea of paralleling the individual 12V blocks is incorrect and contrary to the way that all commercial systems are configured and operated, for good reason.
As you have wired it, you can't check individiual cell or block voltages in isolation. You won't find out you have a bad pack until it has killed those in parallel with it and by then it could have obliterated the whole bank. You should reconfigure it to form parallel series strings ASAP.

3. The powerjack has 2 fuses on both the charger input and AC output side. They are 20mm x 5mm ones but I'm not sure of the rating. They are behind the black screw off caps.
Title: Re: Just bought a powerjack 15000, modding.
Post by: welshman on January 16, 2017, 03:24:29 pm
1. As has already been stated, your RCD won't work without the neutral to earth connection, you should reinstate it, ideally at your main distribution board has has been suggested.

2. Your idea of paralleling the individual 12V blocks is incorrect and contrary to the way that all commercial systems are configured and operated, for good reason.
As you have wired it, you can't check individiual cell or block voltages in isolation. You won't find out you have a bad pack until it has killed those in parallel with it and by then it could have obliterated the whole bank. You should reconfigure it to form parallel series strings ASAP.

3. The powerjack has 2 fuses on both the charger input and AC output side. They are 20mm x 5mm ones but I'm not sure of the rating. They are behind the black screw off caps.

1) this is an isolation transformer, not only would bonding the earth to neutral make touching earth and live dangerous it would also blow up the fets as many have learned the hard way. plus the reason the rcd's wont work, is because the electrical fault condition they detect doesn't occur in the first place.

2) i know that industry practice is not to bond the batteries like this due to the fear of dead cell's, but each battery has a hydrometer and the status of the battery bank is monitored so cell death would be easily spotted. what this method does give as a bonus once that fear has been eliminated is the equalisation of all charge and discharge paths from one end of the bank to the other, improving the battery banks charecteristics.

3) I'm not sure what your mentioning of the fuses are about, i've already replaced them with din rail mcb's.

the system has been working for some time now flawlessly with 9kw+ loads and switching between charge and inverter several times a day without even switching off inverter.

this powerjack with the modifications i have made is powering a whole site flawlessly. washing machines, tumble dryers, double 3kw immersions, kettle. just like being attached to the mains. with a generator coming on and as necessary to keep the batteries from being cycled.

powerjack is an excellent product at an amazing price!
Title: Re: Just bought a powerjack 15000, modding.
Post by: frackers on January 16, 2017, 06:50:48 pm
1) this is an isolation transformer, not only would bonding the earth to neutral make touching earth and live dangerous it would also blow up the fets as many have learned the hard way. plus the reason the rcd's wont work, is because the electrical fault condition they detect doesn't occur in the first place.

I can't help thinking you still "don't get it" about earth bonding.

The secondary of the transformer (i.e. the mains output) is floating and not connected to anything associated with the FETs, the battery or anything else, these are connected to the primary side of the transformer - no electrical connection between primary and secondary whatsoever (only a magnet connection to pass the power through).

For the RCD to operate it must be a part of a complete circuit and one side of that circuit is ground.

I you think a schematic would help I'll knock one up to help explain further.


Title: Re: Just bought a powerjack 15000, modding.
Post by: lighthunter on January 16, 2017, 09:55:08 pm
This is first I have read this thread. Wow, great stuff good thinking guys!! I'm very impressed. Welshman you are one smart fellow. I like challenging ideas that have been in use and understanding thy whys rather than just accepting them as the "right way".

The bird on the wire concept is a great analogy ;D yet the raccoons and squirrels don't fare quite so well  ::) Darn grounds anyway!!

I really cant take sides on this as i see where Frackers is coming from also. I would like to take opportunity to mention one possibility that hasnt been discussed. There is another variable power supply in the sky connected to your home circuit; and you can't isolate its permanent earth ground connection. LIGHTNING, I'm only guessing but i think its the number 1 reason for our earth bonding practices. Lets face it, if direct lightning gets on the hot or neutral  conductors, many appliances will just cease to exist. I suspect an earth bonded home will have a better chance of not starting on fire in such an event. Lightning will find a path one way or another and the neutral - earth bond makes it easier and less destructive for it to do so.

My home has earth bonded to neutral and it also has a steel roof. One precious evening I was enjoying peaceful sleep when I bounced a foot straight up out of bed! I dont know but i suspect the lightning hit the roof. Ive been near lightning before but that was nothing short of an explosion!! There were two breakers tripped and no appliances hurt. Just one of many possible ways that could have turned out.

Frackers, yes our US split phase 120/240 is a nightmare on a good day and is even worse when a neutral connection has trouble which unbalances the center tap placing overvoltage on some appliances and under on others. >:(  I envy you guys with 240 consistent. I do like 60hz better though.

Great discussion, great thread!
Title: Re: Just bought a powerjack 15000, modding.
Post by: mab on January 17, 2017, 04:02:21 pm
have to agree with frackers on the earth bonding issue.

According to BS7671 wiring regs, if you're using a small portable generator for a single appliance then it's better to have a 'floating' output as you then need two faults to create a hazardous condition (not too likely with a single appliance) and as a portable generator is seldom grounded effectively, bonding N-E is of limited use.

If you're using a generator/inverter to supply multiple appliances - say an entire house - then the probability of two faults is very much higher and a N-E bond is the safest option.

The problem with floating output on a multiple appiance system is that the 1st fault grounds one of the live conductors (live or neutral) and you don't know about it as nothing will trip. the second fault will develop one day connecting the other 'live' conductor to earth, but as both faults are downstream of the RCD it doesn't trip.

There is another issue with floating supply besides the RCD: lets suppose a fault develops on a high current circuit; say, your 50A  mcb protected 11kw shower for e.g. - live to gnd - effectively grounding the live wire and making the neutral 230v to gnd. As this is the first fault nothing's going to trip and you remain oblivious to the fault. Then what happen if a fault develops on the 6A lighting circuit neutral to ground? As neutral is now 230v to ground (due to the 1st fault) quite a lot of current is going to flow through your 6A lighting neutral - but your 6A MCB is in the live conductor not the neutral and therefore isn't going to protect the 6A cable - you'd better hope the 50A mcb trips before your lighting cable sets your house on fire! To put some numbers to that:- as lighting circuits often have resistances of 2 ohms (cold wire - it goes up a lot as the copper heats up) that gives us a fault current of 120amps; for a 50A 'B' curve mcb to BS60898, 120A should trip it in 50-100 seconds according to the chart - assuming the wire maintains it's 'cold' resistance - I think a 1.0mm2 lighting cable will be glowing in rather less time than that.

trust me - you should have a N-E bond. :) The original reason for the N-E bond was that the fuses/single pole switches should always be in the live conductor - and that can only be true if the other conductor is grounded.
Title: Re: Just bought a powerjack 15000, modding.
Post by: welshman on January 20, 2017, 04:45:51 am
have to agree with frackers on the earth bonding issue.

According to BS7671 wiring regs, if you're using a small portable generator for a single appliance then it's better to have a 'floating' output as you then need two faults to create a hazardous condition (not too likely with a single appliance) and as a portable generator is seldom grounded effectively, bonding N-E is of limited use.

If you're using a generator/inverter to supply multiple appliances - say an entire house - then the probability of two faults is very much higher and a N-E bond is the safest option.

The problem with floating output on a multiple appiance system is that the 1st fault grounds one of the live conductors (live or neutral) and you don't know about it as nothing will trip. the second fault will develop one day connecting the other 'live' conductor to earth, but as both faults are downstream of the RCD it doesn't trip.

There is another issue with floating supply besides the RCD: lets suppose a fault develops on a high current circuit; say, your 50A  mcb protected 11kw shower for e.g. - live to gnd - effectively grounding the live wire and making the neutral 230v to gnd. As this is the first fault nothing's going to trip and you remain oblivious to the fault. Then what happen if a fault develops on the 6A lighting circuit neutral to ground? As neutral is now 230v to ground (due to the 1st fault) quite a lot of current is going to flow through your 6A lighting neutral - but your 6A MCB is in the live conductor not the neutral and therefore isn't going to protect the 6A cable - you'd better hope the 50A mcb trips before your lighting cable sets your house on fire! To put some numbers to that:- as lighting circuits often have resistances of 2 ohms (cold wire - it goes up a lot as the copper heats up) that gives us a fault current of 120amps; for a 50A 'B' curve mcb to BS60898, 120A should trip it in 50-100 seconds according to the chart - assuming the wire maintains it's 'cold' resistance - I think a 1.0mm2 lighting cable will be glowing in rather less time than that.

trust me - you should have a N-E bond. :) The original reason for the N-E bond was that the fuses/single pole switches should always be in the live conductor - and that can only be true if the other conductor is grounded.

I see, so to make this system safe I need to remove the earth altogether. No earth to sockets or consumer units, just an earth point on the inverters mainboard earth connection for filtering.
Title: Re: Just bought a powerjack 15000, modding.
Post by: Pete on January 21, 2017, 02:52:24 pm
Welshman, what you are wanting to create is a floating voltage system, as mab pointed out, a floating system is reasonably safe as long as there are not many appliances connected to the circuit.
A simple example of what "mab" pointed out would be that the toaster gets an active to frame fault. No problem on a floating circuit, but then say the kettle has a bit of moisture on it and has leakage or a short from neutral to frame. Touching both of these at the same time would put you across the active and neutral.
Like the adage says, "one flash and youre ash"
To avoid problems on a floating system you would have to make sure that  all the switches were double pole. That is switching both the active and neutral.
In Australia this is a requirement for any installation that is supplied by an extension lead.
Really you may get away with the floating system, but I don't see why you want to reinvent the wheel.
What we have in Australia is a Multiple Earthed Neutral distribution system, which prevents the neutral voltage from rising above earth in the case of a fault.
It works very well and RCD's trip when a person gets connected in the wrong places. I can attest to their fantastic service, Once while working on an amplifier I turned it around to get to the bottom of the board to check voltages, accidentally touching the fuse on the amp. Zap, then nothing, the RCD tripped.
It seems to me that power supplies are set up by pretty smart people, I worked as an electrician and contractor for most of my working time and am happy to take their advice.
Pete
Title: Re: Just bought a powerjack 15000, modding.
Post by: mab on January 23, 2017, 05:33:59 pm
Quote
I see, so to make this system safe I need to remove the earth altogether. No earth to sockets or consumer units, just an earth point on the inverters mainboard earth connection for filtering.

don't be daft!

Quote
I've also decided to leave neutral floating and not connected to earth. In my mind if between part of the circuit board where the powejack has  the "neutral" path and the appliance is damaged in someway where it is now an open circtui and it is bonded to earth then the current will be sent down the earth wire. If this path happens to be more conductive at the appliance to ground than all the way back to the grounding rod, there could be a situation where there is a high voltage on the negative/neutral and anyone touching an appliance metal casing in this situation could receive a shock.

Contrary to popular belief, electricity takes all paths back to its source, not just the path of least resistance.

It may well be fine bridging earth to neutral in the consumer unit/main panel on mains where it's unlike that the neutral will break to the grid. But when relying on a circuit board made in china to a questionable quality, I'm not going to take the risk of bridging earth to neutral, I'm far safer not doing so and using a RCBO with less then 30ma trip, which monitors earth leak and neutral / hot sync.

The generator in using has its own earthing rod. It also has its neutral bonded to earth. The inverter and the entire sites wiring are on a seperate earth rod to the generator.

I re-read that from your earlier post to try and get my head around your thinking, and I can't quite see what the powerjack pcb's have to do with it; In my house the PJ is just a box providing the AC supply, the N-E bond is downstream of the PJ and before the main RCD and consumer unit. If the PJ develops a fault I lose the AC but the house stays safe regardless of how the PJ fails.

The only thing I can see in your system where a n-e bond at the 'house' may be an issue is when running the generator through the PJ, because the generator has it's own n-e bond. You should only ever have one n-e bond.  In this case the loss of the neutral between the genny's n-e bond and the house n-e bond would push the house neutral (and earth) up to a hazardous potential relative to ground by pushing the neutral current through the rods -  so I'm guessing this is what you meant.

If that's the case, the better solution might be to bond the house earth and the genny earth together (I'd do that anyway) make the n-e link at the output of the PJ and remove the n-e link at the generator - although this assumes you aren't going to use the generator independently of the house. If you do want to use the generator at times when isolated from the house, you could use a changeover switch with a n-e bond on the local output at the generator, so that the generator only sees the n-e bond at the house OR the one local to the generator.

hope that makes sense.
Title: Re: Just bought a powerjack 15000, modding.
Post by: welshman on March 01, 2017, 08:17:34 am
After working flawlessly for some time , I've decided to bond the earth and the neutral at the mainboard of the PJ yesterday. Will see how it behaves, if the FETs blow etc. So far so good.
Title: Re: Just bought a powerjack 15000, modding.
Post by: Fionn on April 25, 2017, 05:00:19 pm
Haven't been here in a while, just to recap on your earlier post.


The only way of getting a shock is by touching both the live and neutral at the same time.. which an RCD won't protect against anyway.
This is incorrect, in a normal neutral-earth bonded installation with RCD protection where someone touches live and neutral at the same time, current will flow to earth as well as from live to netural through the person's body.
To quote yourself, current takes every path available, not just the one of least resistance. This at least gives a chance that the RCD will protect the user assuming the fault current to earth exceeds 30mA - which is quite likely.

in a neutral earth bonded system you could touch the live and earth at the same time to get the same result so in this respect it's actually worse.
While I understand that you are saying that there is an increased number of fault scenarios, my earlier point stands and a servicable RCD will definitely trip in a live to earth fault.

Also if we removed the earth altogether from the system and isolated the inverter so it wasn't earthed either and throwing away the rcd, that would ironically be the safest option. Birds don't get electrocuted sitting on the live wire as in this situation we have an isolation transformer we shouldnt get a shock either.

The only way something could go wrong is if another appliance shorted "neutral" to the same physical ground or casing you are in contact with and also touching the live wire.
You have correctly identified the flaw in this scheme. Without monitoring, the supposedly isolated system can become referenced to earth at any time and you will be unaware until there is a fault.
Just remember that the live could just as easily be referenced to earth as the neutral. Initially this won't cause an identifiable problem. However this could lead to the casing of your inverter (or any other connected appliance) assuming a potential of -230V if there was a neutral to case fault on any appliance (which is of course isolated) potentially delivering a fatal shock to anyone that comes in contact with it.

As far as i can tell the only reason the RCBO wont trip is because youre not getting a shock.
You are correct but you now have no way of testing your RCBO in your installation so you have no idea if it will work when you need it or not.

I have a gut feeling the entire electrics industry grounds neutral for voltage stability and pretends in some far fetched situation it provides safety.
I'm sure you're joking and can appreciate that international electrical specifications are drafted by well meaning educated professionals - pro bono in my country, in the interest of public safety.
Title: Re: Just bought a powerjack 15000, modding.
Post by: Fionn on April 25, 2017, 05:06:04 pm
2) i know that industry practice is not to bond the batteries like this due to the fear of dead cell's, but each battery has a hydrometer and the status of the battery bank is monitored so cell death would be easily spotted. what this method does give as a bonus once that fear has been eliminated is the equalisation of all charge and discharge paths from one end of the bank to the other, improving the battery banks charecteristics.
It is possible that at some point you will develop a short in one of your cells - which could happen at any time, will just take a piece of plate material to drop off in an unfortunate position.
When this happens, that cell and all the other cells which are in parallel with it will discharge through it at high current.
If you're lucky, this will only mean that you destroy every block in that parallel string but it is far more likely that you will have a significant thermal event - fire and / or explosion when it happens.
If not, you will just kill all the other blocks in the pack from overcharge as your generator will likely kick in immediately and overcharge the surviving blocks.
It's possible that this may not happen within the lifetime of your installation, but you're certainly rolling the dice.
Title: Re: Just bought a powerjack 15000, modding.
Post by: rossw on April 25, 2017, 05:19:39 pm

The only way of getting a shock is by touching both the live and neutral at the same time.. which an RCD won't protect against anyway.
This is incorrect, in a normal neutral-earth bonded installation with RCD protection where someone touches live and neutral at the same time, current will flow to earth as well as from live to netural through the person's body.

I hate to correct your "correction", but you are also in error under certain circumstances.

If you'd said that current "MAY flow to earth" and indicated that the RCD "MAY" trip, I'd have left it.
There are plenty of cases where there is insufficient out-of-balance current to trip an RCD, and I can testify to it myself.

Electrical Safety equipment certainly increases your chance of survival significantly, but it doesn't guarantee to save you in 100% of instances!
Title: Re: Just bought a powerjack 15000, modding.
Post by: Fionn on April 25, 2017, 05:43:20 pm
I agree wholeheartedly Ross, the fault current to earth would still have to exceed 30mA of course, I was merely trying to illustrate that the standard approach at least has a chance of working in that fault scenario. Some current will certainly flow to earth however so I don't think "may" is appropriate, the only uncertainty is around the quantity.
An unmonitored distributed isolated system has a far greater chance of causing unintended death however.
This thread is rife with practices that should never be followed.
Title: Re: Just bought a powerjack 15000, modding.
Post by: Fionn on April 25, 2017, 06:13:35 pm
Hang on, scratch that Ross, I fully qualified in my original post that the fault current would have to exceed 30mA - directly under the line you quoted.
Title: Re: Just bought a powerjack 15000, modding.
Post by: rossw on April 25, 2017, 06:29:29 pm
Hang on, scratch that Ross, I fully qualified in my original post that the fault current would have to exceed 30mA - directly under the line you quoted.

And I contend that there are plenty of times when standing, working on something where there would NOT be any earth current if you got tangled up across active/neutral and that therefore the RCD would NOT operate.

My workshop floor for example, has large rubber mats - mainly to reduce foot and leg fatigue.
Over my many years working on stuff, I tend NOT to lean against or otherwise contact the metalwork of equipment, switchboard frames, equipment enclosures etc.
So tell me where the earth current would come from when I've got the covers off a "thing" and get myself across Active and Neutral??
Title: Re: Just bought a powerjack 15000, modding.
Post by: Fionn on April 25, 2017, 06:36:27 pm
There will always be some earth current, unless you're floating in mid air, it might be micro amps but there will be some path to earth if the system is earth referenced.

The example you give is not really relevant to the safety of a standard electrical installation whatsoever in any case. You have created an insulated matting and adapted your behaviour to avoid creating earth paths by your own admission - hardly typical of the usage of standard electrical appliances.

Regardless, this is a moot discussion, I clearly stated in my post that protection would only be provided if the fault current exceeded 30mA.
We're in agreement so I don't see what we're adding to the discussion at this point.

Or are you in fact arguing in agreement with the OP that we should do away with earth referencing and RCD protection and go with unmonitored floating installations?
Title: Re: Just bought a powerjack 15000, modding.
Post by: welshman on May 19, 2017, 04:42:31 pm
There will always be some earth current, unless you're floating in mid air, it might be micro amps but there will be some path to earth if the system is earth referenced.

The example you give is not really relevant to the safety of a standard electrical installation whatsoever in any case. You have created an insulated matting and adapted your behaviour to avoid creating earth paths by your own admission - hardly typical of the usage of standard electrical appliances.

Regardless, this is a moot discussion, I clearly stated in my post that protection would only be provided if the fault current exceeded 30mA.
We're in agreement so I don't see what we're adding to the discussion at this point.

Or are you in fact arguing in agreement with the OP that we should do away with earth referencing and RCD protection and go with unmonitored floating installations?

Thanks for your input, but at the end of the day the result of the situation is this..

I have gone from not being able to get a shock from touching the live wire to now being able to get a shock from touching the live because i've bonded the earth to neutral...

but everyone tells me i'm now safer.

i'm still trying to figure that one out exactly. ;)

Title: Re: Just bought a powerjack 15000, modding.
Post by: welshman on May 19, 2017, 04:44:50 pm
In case anyone is wondering the system has been switching itself to charge/inverter mode daily upon startup of generator with the earth bonded to neutral for some time now and the fets have not blown as i had worried might have.

looks like despite the manual for the pj telling you to switch it off and on when the input power is established or lost the unit doesn't seem to blow up like they used to.

they must have done some clever stuff with the ramping up of the power on the newer boards.
Title: Re: Just bought a powerjack 15000, modding.
Post by: Fionn on May 19, 2017, 04:50:24 pm
You're correct, until you have one fault your current system is safer.

The issues is that when that fault develops, you'll have no way of knowing it and then when you get a second fault it could be fatal.

It's essentially an IT type electrical system that you've created if you want to research that. They're used in industry where high reliability is required but always with a monitoring system that monitors resistance between live, neutral and earth at all times.

They're not really suitable for domestic general distribution due to the risks and the fact that faults can be hard to track down.

That's promising on the power jack boards, I've kind of converted to the EGS002 ones myself though myself.
Title: Re: Just bought a powerjack 15000, modding.
Post by: welshman on May 20, 2017, 03:06:09 pm
You're correct, until you have one fault your current system is safer.

The issues is that when that fault develops, you'll have no way of knowing it and then when you get a second fault it could be fatal.

It's essentially an IT type electrical system that you've created if you want to research that. They're used in industry where high reliability is required but always with a monitoring system that monitors resistance between live, neutral and earth at all times.

They're not really suitable for domestic general distribution due to the risks and the fact that faults can be hard to track down.

That's promising on the power jack boards, I've kind of converted to the EGS002 ones myself though myself.

then i think we can all agree that if we had a device called a "neutral grounding resistor monitor" connected up, which would then trip the breaker if there was a connection between earth and neutral while leaving 'neutral' floating and not bonded to earth, we would have the safest system going?

Title: Re: Just bought a powerjack 15000, modding.
Post by: Fionn on May 20, 2017, 04:49:52 pm
Yes I agree it would be very safe, however I believe such a system would be unworkable for general distribution for at least 3 reasons.

1. Cost - the monitoring devices are expensive, at least I'm not aware of any easily available inexpensive ones.

2. Lack of discrimination - A fault anywhere on the system has to bring down the entire supply. So your immersion heater for example could go faulty and that leaves you with no power until you track down the fault (which would take a while) and repair it. The more extensive your distribution the more complex this becomes.

3. False alarms - In order to be useful the system would be need to be set at a quite sensitive setpoint. Since you have to monitor the entire system as one, a long term deterioration in one or many devices could combine to lower the resistance to earth close enough that it could trip unnecessarily during periods of high humidity for example.

Hope that makes sense!


Title: Re: Just bought a powerjack 15000, modding.
Post by: MadScientist267 on May 20, 2017, 04:51:17 pm
then i think we can all agree that if we had a device called a "neutral grounding resistor monitor" connected up, which would then trip the breaker if there was a connection between earth and neutral while leaving 'neutral' floating and not bonded to earth, we would have the safest system going?

I believe that takes this full circle. Here, we call that a GFI/GFCI/RCD/PITA  ;D

I encountered this issue with the truck and it's umbilical cord connection, and wrestled back and forth with what was the best way to provision for every scenario I could think of... the answer? There wasn't one. Not that covered them all at least.

In the end, I went with looking at the truck as an "appliance" that has most of its threat potential inside of it, and gave it its own internal N-E bond, complete with a set of downstream GFIs. Once someone is inside, there's no more threat of getting zapped than in a normal everyday dwelling wired for AC.

The caveat to this is that because of the tires, it is for all intents and purposes inherently isolated from earth, as the "single appliance". The problem then became how to deal with bonding the frame to my upstream source's ground to keep it at earth potential, while keeping an upstream GFI happy under no-fault conditions. Put simply, it wasn't possible to do *both* internal and external safety protection to my satisfaction at the same time.

If the upstream connection is to a non-GFI protected source, the earth bond is more important than ever, because if I'm parked on grass or the asphalt is wet, there's a much higher chance that anyone with one foot on the ground and the other on the rear bumper will be part of a lower resistance path at both, than if it is parked on pavement and everything is dry.

Having the internal N-E bond however, this means that the normal current return path would share with the earth lead.

If there *IS* an upstream GFI (a scenario I only envisioned as likely to increase in probability of encountering), this results in an immediate trip of the GFI with nothing more than the *capacitive reactance alone* of the internal wiring connected as a "load".

As a side note, this was a bit baffling until I realized (and subsequently confirmed) that this was what was happening... the fluke was showing completely open resistance measurements, but that is done with DC. AC had snuck parasitic capacitance in under my nose. This however is ultimately moot, because even without it, the moment a real load gets applied, the same result happens.

What I ended up doing was placing a "jumper" in that could leave the truck frame and umbilical disconnect/breaker box bonded to the umbilical's earth, still leaving the internal bond in place to provide the protection on the inside. This of course then ultimately means that an open (or other) neutral fault between the truck frame and upstream source's N-E bond relies on the upstream GFI to prevent shock hazard conditions. Again, I weighed this against the idea that it's then essentially the equivalent of grabbing a toaster chassis in an up-to-code kitchen in terms of threat. GFIs fail too, after all, but that failure would need to be combined with the open neutral or other fault to become a problem.

Whether or not to have the jumper in place of course requires knowledge of the upstream system I'm connecting to... which leads me to a final point...

The thing I keep seeing here, and it's either overlooked, ignored, or rationalized away, is something that was ingrained in me early on: "Treat every wire as if it can kill you". You can rationalize and argue against the idea that its possible all day long, but get into an argument with physics, and (I really hope) I don't need to justify my reasoning for betting on my choice as to which one will win, right?

As for isolation transformers: Under the wrong circumstances, they *will NOT* save your neck. They're designed in general to isolate power and ground leakage to levels that *equipment* can safely tolerate, not people. Don't fool yourself into thinking otherwise. If you don't believe me, connect one with only the hot side connected to the appropriate primary terminal, and leave the neutral and ground disconnected... then check how much AC current is available between one of the secondary leads and earth...

You no longer have a transformer... you have a *capacitor*, a non-trivial one at that, which passes AC rather freely. Still think it'll save you?

</rant> </2cents>

Steve

Title: Re: Just bought a powerjack 15000, modding.
Post by: welshman on November 26, 2019, 06:03:29 am
Update.

Got some LTO batteries, been running with them for a couple of months now and they have changed everything. Charge amazingly fast, ZERO fire or acid hazard.

I got tired of exploding lead acid batteries and needed to eliminate the dangers with them. I looked on ebay a few months ago and found these for sale. When I collected them I discovered they were aviation batteries and had been submerged in silicon oil their entire life. They were pristine.

I matched the number of cells to the inverters range of power, they can never over charge and they can never under volt.

Worked out amazing and was cheap.

Currently working on a raspberry pi to replace the generator controller. using peacefair pzem-017 module to monitor the batteries.
Title: Re: Just bought a powerjack 15000, modding.
Post by: welshman on November 26, 2019, 06:04:54 am
In case anyone is wondering, the inverter is still going strong without any replacement parts needed yet. In use daily as a mains power supply.
Title: Re: Just bought a powerjack 15000, modding.
Post by: Wolvenar on November 30, 2019, 07:08:29 am
That looks like a nice find.

I would love to see the raspberry pi controller build documented.
I have a similar project upcoming.
Title: Re: Just bought a powerjack 15000, modding.
Post by: welshman on December 01, 2019, 06:01:02 am
That looks like a nice find.

I would love to see the raspberry pi controller build documented.
I have a similar project upcoming.

will provide all findings.

what I have so far is a raspberry pi 3 B v1.2 running windows 10 IOT and a universal windows application written that communicates with a peacefair energy monitor using Modbus protocol over rs485 via a cp2102 chipset ttl and a rs485 to ttl converter plugged into a USB port on the pi.

the GUI on the pi output via 7" hdmi touchscreen shows the various settings for the conditions in which the generator starts and shows realtime voltage and amp values off the peacefair module with 3 graphs to show the past 2 minutes of values. it logs the data to sd card every 5 seconds.

I also built in a webserver in the application so that settings can be remotely displayed and changed.

the application is written with visual studio 2019 and written to run on arm or x86/64 I will post the solution.




Title: Re: Just bought a powerjack 15000, modding.
Post by: dochubert on December 03, 2019, 09:18:03 pm
Hi Welshman,
I'm jealous of your battery bank.  Did you mention the AH rating?  I'm still using sla batteries for at least 5 or 6 years, until these die.

Did your question about the mosfets get answered?  I didn't see it if so.  I'm interested in the answer myself.
Are the hy3810 fets currently used by powerjack good ones?  Better than the 4110 fets in my older 15kw?  Is there a better choice than either?  I wonder why powerjack switched?

Good luck on your project!
Title: Re: Just bought a powerjack 15000, modding.
Post by: welshman on December 04, 2019, 12:45:28 pm
Hi Welshman,
I'm jealous of your battery bank.  Did you mention the AH rating?  I'm still using sla batteries for at least 5 or 6 years, until these die.

Did your question about the mosfets get answered?  I didn't see it if so.  I'm interested in the answer myself.
Are the hy3810 fets currently used by powerjack good ones?  Better than the 4110 fets in my older 15kw?  Is there a better choice than either?  I wonder why powerjack switched?

Good luck on your project!

lithium-titanate has a c20 charge rate, cycle count of 20,000, they can be squashed, drilled into and blowtorched and no harm will come to the person doing it. they can not set fire and can not explode ever, safest battery on the market. cell nominal voltage is 2.3 , charge is 2.7 and cut off low voltage is 1.7. in each series there are 23 cells, and 4 series in parallel. giving nominal voltage per series of 52.9, charge voltage of 62.1 and low voltage cut off at 39.1.

Making all those voltages ideal to the inverters specifications. The inverter low voltage cuts off at 40 volts, which is above the batteries low voltage specification, automatically keeping them safe. no extra under voltage protection needed. Also, no equipment feeding power into the dc; inverter, solar and wind, is going to be able to provide more than the batteries 62.1 charge voltage, again automatically keeping them safe from over charging.

I believe the batteries are only 30 AH, but I have no documentation stating this. I was only told, however due to the size of them I can believe they are at least that. i'm unable to even identify who makes the product, it appears to be specialist aircraft style design. However, the performance of these batteries is amazing. They can cope with huge amounts of currents in bother directions, which in itself is a safety risk, so fuses must always be used. They have a very impressive power curve, almost acting like full right down to the last drop of juice in them. right down at 42v I can pull a 6kw load without it dropping the voltage. They don't seem to jump like the lead acids did, just a steady drop in voltage increasing or decreasing speed, fluidly with load change.

To give you an idea what they are like, they out perform the original 16 x 130AH SLA's I had. Were getting twice the amount of uptime between needing to topup with generated power and have reduced the amount of time the generator is running, we're noticing the saving in fuel with them.
Title: Re: Just bought a powerjack 15000, modding.
Post by: dochubert on December 06, 2019, 05:58:21 pm
The more you describe those batteries, the better they sound!  I just looked on ebay and found nothing like the bank you bought, and those I did find for sale were pricey for not too high AH rating.  Any chance your seller still has some like yours for sale??

Also, 48v powerjack inverters alarm at 59 and shut down at 60 volts so might want to adjust for that.  (22 cells instead of 23 would give you a range of 50-59 volts.  just a thought)   
Title: Re: Just bought a powerjack 15000, modding.
Post by: welshman on December 08, 2019, 04:00:32 am
The more you describe those batteries, the better they sound!  I just looked on ebay and found nothing like the bank you bought, and those I did find for sale were pricey for not too high AH rating.  Any chance your seller still has some like yours for sale??

Also, 48v powerjack inverters alarm at 59 and shut down at 60 volts so might want to adjust for that.  (22 cells instead of 23 would give you a range of 50-59 volts.  just a thought)   

The batteries seem to have gone off ebay, they must have all been sold. I still have the contact details of the seller if you wish.

My powerjack goes all the way up to 62 volts without complaining.. maybe ive disconnected something related to that?
Title: Re: Just bought a powerjack 15000, modding.
Post by: dochubert on December 08, 2019, 12:41:01 pm
The overvoltage setpoint was controlled by resistor R14 on the top of the older (v3.x) control boards.  In some of these powerjack moved the resistor to the underside of the control board(no idea why). 
Oztules discovered that piggy-backing a zener diode to this resistor caused the overvoltage shutdown and alarm to not happen.  Sometimes my pwm controllers spiked above 60v, so I changed the resistor value on mine because I didn't want to completely eliminate the shutdown/alarm, but didn't want it so tight at 60v.  I piggy-backed a second 10m resistor, changing it to 5m, which seems to work satisfactorily for me.  Spikes no longer tripped my inverter offline.
The newer modular control boards (v7 and up) have a built in overvoltage adjustment pot which I have not messed with as I haven't yet had an issue with my newer inverter.  My new water heater dump load is likely preventing it reaching 60v.

Then there's the temperature issue.  It's not supposed to be a factor, but my testing showed that it is.  Higher temperatures sensed by the heatsink and transformer temp sensors lower the trip point of the overvoltage shutdown.
In your case my guess is that yours runs cool enough because of your reconfiguring the mounting layout that you don't get a trip at 62v.  Have you run it in hot weather/high ambient background temp?  Do you run your fans all the time?

Anyway, since you're not getting alarms/shutdowns, no sense changing anything.  If you start to get alarms in hot weather though....

I'll keep watching for batteries like yours as they seem to have several advantages over other types.  Not really ready to change mine yet but if opportunity knocks....
Title: Re: Just bought a powerjack 15000, modding.
Post by: welshman on September 10, 2020, 02:03:21 pm
in progress
Title: Re: Just bought a powerjack 15000, modding.
Post by: dochubert on September 10, 2020, 10:10:27 pm
Hi Welshman,
Good to see your post.
Looks like you had a smoke test.

Are you going to rebuild the lf driver board or replace it?
Title: Re: Just bought a powerjack 15000, modding.
Post by: welshman on September 11, 2020, 06:50:31 am
Hi Welshman,
Good to see your post.
Looks like you had a smoke test.

Are you going to rebuild the lf driver board or replace it?

Hi, dochubert, I'm now on my second smoke test. :D

I've got one driver board on order and two dead boards. I've got a load of NY and MY's, will replace those on the driver boards first as I'm sure they will have blown and test other components then rebuilding them. Will be having a go at repairing everything.

The mostfet boards sm-resistors have all been damaged, except one or two. incorrect resistance now being read with multimeter. So everything except the led and it's resistor are being replaced.

Handy RJ-45 connector was used as a spacer to fit the mosfets.

I have a few control boards now and have also acquired a nice giant chloride motive power 48v+ battery charger.  Will push 60v@70+amps into the batteries, but it gets very hot on the transistor side. It has a giant EH transformer in it, very heavy. Going to turn this into a backup, just need to get hold of a few power boards. Either from powerjack or have them made by pcbway.com using oztules gerber files. i would have already ordered them off pcbway, but the oztules gerber files i have scavenged from old threads don't seem to display correctly, the drill holes are in the wrong place.

The idea is to have a backup inverter using this, don't care about efficiency. It gets expensive to run a 18kw genset all the time while the powerjack is down for repair.

Ill be doing an overhaul on the unit this time. Suspending those toroid's using straps to expose the center and back to air cooling. Will help keep things cooler on those roasting hot days summer days, if we have any. Moving a few things around to make repair easier and tidying up the wiring and mounting external fuse box to avoid opening to see fuse states.

ive included a few screen shots from the software i wrote for the raspberry pi that monitors the voltage of the batteries and controls the inverter faults/generator start stops. i thought you would be interested to see how the LTO batteries handle to loads.

Title: Re: Just bought a powerjack 15000, modding.
Post by: welshman on September 11, 2020, 12:34:51 pm
so far so good, two done. 6 more to go..

Title: Re: Just bought a powerjack 15000, modding.
Post by: welshman on September 11, 2020, 01:20:46 pm
on further inspection, i think i've got R14 wrong.. on my original boards that came with my powerjack they are 220ohm (2200 SMD CODE) but some of the replacement boards that i received have 47ohm as R14. 

Which is a bit confusing.

I need to swap what i've done with a 220ohm instead of 22kohm that i've mistakenly put there now.
Title: Re: Just bought a powerjack 15000, modding.
Post by: welshman on September 11, 2020, 01:57:10 pm
is it 47ohm for the DC side mosfet board and 220ohm for the AC side mosfet boards for R14?

or does it matter, because i've been told from a reliable source that the AC boards work for both sides, but the AC boards have to be on the AC side due to there being ferrite beads on the centre leg of the fets?

the replacement fets ive received (cheap from china) are showing 4.3Mohm from drain to source.. the originals are 2.9Mohm, obviously they are going to get a bit hotter, but does 4.3Mohm make them unusable?

going for some hy4008 next time i order. wondering if i should stick to the P package or go for the W package with bigger legs. does the W in TO-247 format make good electrical contact with the heatsinks considering the centre hole has plastic inside it?
Title: Re: Just bought a powerjack 15000, modding.
Post by: welshman on September 12, 2020, 12:15:20 pm
both NY's on the lf driver board were shorted. replaced those, dont have any MY's, they're in the post. but they don't seem to be shorted. checking everything else as i go.

got a couple more mosfet boards made up. looking like new, i think.

a lot of 57ohm's were fried. 20k's not so much.

im a bit concerned about them being fake hy3810's due to the higher resistance and the package/logo is a little different, lets see what happens.

once the MY's here, should be next week and im confident the driver board is repaired. ill put it back together and see if it works.

if all good ill get started on making another inverter.
Title: Re: Just bought a powerjack 15000, modding.
Post by: welshman on September 15, 2020, 03:13:43 pm
inverter is back together and working with the new mosfets and repaired lf drivers. all 4 of the NY and MY chips on the lf driver needed replacing. The cheap HY3810  @ 4.3MOhm , seem to work just fine so far today. Even going back and forth into charging mode is working without blowing them up today.

only difference so far with these cheap fets is a slightly higher idle load.. not sure if it's related.

Next up, backup inverter build.. this is going to be something interesting, I'm sure it will be a mold breaker. new thread coming soon.
Title: Re: Just bought a powerjack 15000, modding.
Post by: Pete on September 15, 2020, 05:35:14 pm
Good to hear that you got the beast working again.
I just recently bought an 8000 watt 24 volt powerjack. It had issues that I managed to sort out without blowing it up.
The output board was shorting to the transformer mount, the active and neutral were transposed which meant it shorted out when connected to my MEN connected switchboards, and a screw was rattling about inside from one of the mosfet boards.
Not much really except deadly to an unsuspecting user who would have been fooled by the switches not turning the active off on their power outlets.
The inverters work well once they are checked and tested.
Pity that some like yours decide to emit smoke and need more intense surgery.
Hope it goes well , look forward to seeing the new inverter you are planning on building
Pete
Title: Re: Just bought a powerjack 15000, modding.
Post by: welshman on September 30, 2020, 07:19:59 am
it didn't last long Pete. They were in fact fake hy3810's which was evident after they blew. they ran very hot even at idle.

they lasted 24hrs total and blew up.

here is a comparison of the genuine vs fake hy3810's. the fakes are quite easy to spot now i know what im looking for.

i have now switched over to hy4008 anyway.

Title: Re: Just bought a powerjack 15000, modding.
Post by: Wolvenar on October 02, 2020, 02:39:55 am
I went through nearly the same about a year ago with a motor control.
Fakes are EVERYWHERE anymore. I wound up biting the bullet and paying premium cost from Digikey.
I live nearby so I just nabbed them on a trip past Thief River Falls (Minnesota) so I saved the shipping at least.
Title: Re: Just bought a powerjack 15000, modding.
Post by: welshman on October 17, 2020, 10:25:51 am
I went through nearly the same about a year ago with a motor control.
Fakes are EVERYWHERE anymore. I wound up biting the bullet and paying premium cost from Digikey.
I live nearby so I just nabbed them on a trip past Thief River Falls (Minnesota) so I saved the shipping at least.

both these was the genuine seller https://www.ebay.co.uk/itm/10pcs-OEM-HY4008P-HY4008-80V200A-TO-220-MOS-Replace-IRFB3207ZPBF-RU190N08Q/123506575104
https://www.ebay.co.uk/itm/50PCS-X-HY-HY4008B-TO-263-2-N-CH-MOSFET/333533302689

just to update the status. got some genuine hy4008's from an ebay chinese seller. bought 60 hy4008p and 50 hy4008b's for the backup. they should last me through a few years. have experienced 3 blowouts on resuming from grid/charge to inverter mode, twice with genuine mosfets hy3108's and once with fakes that lasted only a day. 3 lf driver boards have blown and nothing on the control boards or the mosfet boards has been damaged apart from the smd resistors on the mosfet daughter boards. all 3 driver boards have been repaired and confirmed working with only replacing two pairs of MY and NY chips.

everything is up and runnign again, but now using hy4008p's instead, left everything else electronically the same, currently powering it down before finishing charge from generator until backup unit has been built. which im just waiting on one crucial part so i can finally assemble all the bits ive made and amassed for it.

once the backup is up and running ill be resuming with taking my chances. it lasted several years with multiple daily charge/inverter changes without powering down. i blame the relay on the board due to the condition it is in and taking so long for the first set of mosfets to die. the relay is rated at 30 amps, so it's already under spec. i initially changed it for a solid state relay as i discussed in the other thread , but it failed to work as expected and i've not investigated it yet. i switched it for a good quality 50 amp relay that has a clear casing so i can keep an eye on the contacts. i might be barking up the wrong tree here with the relay being the possible problem. time will tell.

just ordered a set of these

https://www.ebay.co.uk/itm/E8020-E80-Ferroxcube-3C90-E-EE-Ferrite-Cores-transformer-AL-5000-1set/370683164776
Title: Re: Just bought a powerjack 15000, modding.
Post by: solarnewbee on October 20, 2020, 09:46:55 am
Hi welsh!

I bought some of those cores some time ago from an electric supply company along with the plastic winding cores so I could use thicker copper with thinner insulation without fear of cutting insulation. What a dramatic change In idle and running efficiency. Shortly after I replaced that 24v 15kw with a 48v 15kw made the same mod and shipped it out to Philippines. That will be a FaceTime install. Just did a switch to Lifepo4 in our 5 person e-bike tricycle over FaceTime. My daughter learned a lot about battery terminal and arranging them so it should go well. I also removed the steel plate and rubber from the top of the coil and attached the fan with standoffs to blow cooling inside coil. This version comes with a fan installed above the coil.  I couldn’t  put rubber blocks under coil like suggested by Doc and ship it safely so later when I travel next year I will make the change.  Also in stalled a 4 fan pwm fan control with one temp sensor on the coil and the other on the heatsink that warms up the most.

Keep up the good work guys. Best of luck and Best Regards!