Author Topic: Just bought a powerjack 15000, modding.  (Read 20800 times)

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Offline Pete

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Re: Just bought a powerjack 15000, modding.
« Reply #45 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

Offline welshman

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Re: Just bought a powerjack 15000, modding.
« Reply #46 on: December 06, 2016, 10:55:17 am »
almost there now.

information/explanation and better images will be uploaded soon.

Offline welshman

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Re: Just bought a powerjack 15000, modding.
« Reply #47 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


Offline welshman

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Re: Just bought a powerjack 15000, modding.
« Reply #48 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.


Offline welshman

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Re: Just bought a powerjack 15000, modding.
« Reply #49 on: December 08, 2016, 12:10:34 pm »
Modified Power board.

Offline welshman

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Re: Just bought a powerjack 15000, modding.
« Reply #50 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.

Offline Pete

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Re: Just bought a powerjack 15000, modding.
« Reply #51 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

Offline welshman

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Re: Just bought a powerjack 15000, modding.
« Reply #52 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.


Offline welshman

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Re: Just bought a powerjack 15000, modding.
« Reply #53 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.



Offline welshman

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Re: Just bought a powerjack 15000, modding.
« Reply #54 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?

Offline frackers

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Re: Just bought a powerjack 15000, modding.
« Reply #55 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!!

Robin Down Under (or are you Up Over!)

Offline welshman

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Re: Just bought a powerjack 15000, modding.
« Reply #56 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.

Offline welshman

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Re: Just bought a powerjack 15000, modding.
« Reply #57 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.

Offline welshman

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Re: Just bought a powerjack 15000, modding.
« Reply #58 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?

Offline Wolvenar

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Re: Just bought a powerjack 15000, modding.
« Reply #59 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.
Trying to make power from alternative energy any which way I can.
Just to abuse what I make. (and run this site)