guess who bought a power jack inverter

[rossw]

what are Transorbs?

To all practical purposes, they're zener diodes.
(There are AC and DC transorbs, AC ones are like a pair of series-back-to-back zeners)

Basically, they're VERY fast avalanche diodes.

[oztules]

Transorbs  ( actually tranzorb) are transient voltage  suppressors ( TVS ) as Ross says, and you will find one under the control board... an obvious add on It is straight across the 12v to protect from  spikes getting past to the computer i suspect.  ( a add on wire is also there on mine for the 12v to the front socket for the display power)

They are zenners with a difference. The ones I had are bidirectional, and stand surges of 1500watts  for a pulse and a few hundred amps...... then they die short if things go pear shaped.

They do work there too... if you incinerate the totems, there is a fair chance you will blow a diode in the pwm supply, and the tranzorb will go shortcircuit, and protect the logic end.

Gonna try the .1cap and 2k7 again, but this time lift 5 of the 20k resistors off the board. This will give me a better chance of seeing a proper waveform.. AND a decent voltage... and the 20k can still hold the gates at ground through the other gate resistors ... we'll see..

Frackers, can you get a picture of your boards please. These are the latest model I suspect, and I see they are selling fet boards ( 6 fets, a small board, and heat sink that bolts to the fet card... interesting concept...



So detachable fet cards now. If they don't degrade performance, these things are definitely for remote area use...... don't need a soldering iron to fix the fets.....wow  ... neat idea.    are yours this type too?

Here for interest:
 http://www.ebay.com/itm/New-LF-powerjack-pure-sine-wave-power-inverter-detachable-mosfets-board-parts/111648922855?_trksid=p2047675.c100005.m1851&_trkparms=aid%3D222007%26algo%3DSIC.MBE%26ao%3D1%26asc%3D30542%26meid%3D77721b77aec34f5ba0d569976f26e53a%26pid%3D100005%26rk%3D2%26rkt%3D6%26sd%3D121372307145&rt=nc

...........oztules

[frackers]

Yup - mine look like that. Not knowing a lot about what older ones look like, the high side appears to have a ferrite bead on the gates, otherwise I think high & low side are the same. Lots of brass on the connectors so I would say they'll be OK with the high currents.

I'll take some pics tonight when i get home!

No idea how this lot connects up - my first guess is the primary of the transformer goes between the 2 rows of heat sinks where one row is also battery +ve.

[oztules]

Yep the 4 or 6 black leads ( depends on 8 or 15kw boards) go to b- Big heat sink to b+ two smaller heats sinks to transformer.

....oztules

[oztules]

Some pics of the wave format 1us resolution... not too shabby for the RC network either.

First normal:



The with 5 source gate resistors removed to take the new gate source up to 20k total, and the 330n cap with a 2k7 resistor across it in series with the input to the fets for a cap drive. Still with the tranzorb across the totems... now way would they blow them up now.... but the voltage is a bit attenuated... hmmmm




So the EE was right.

Now to see if we can improve it any more...... and no jokes about my crappy scope  ... the fancy bells and whistles dual trace overhead fox tales  and chrome handles  Phillips one lasted only a year or so ... I have had this 30 years.... and it was old when I got hold of it......

On the first one,Interesting that  it is nearly fully on in about 50ns and about 200ns full rise time...... wonder how much better we can get it now we have looked at it.

This is on a test bed on the bench, so no inductor on the small transformer I'm using ( about 5-800 watts )

Total control board protection looks within reach now.




..............oztules

[RBT]

Hi

First post here, please be gentle

I've read most of the thread (and understood little, have to admit). I bought a 6000-12-230 a few months back as I needed a battery charger and a large capacity inverter to start the pool´s pump and some tools in my shed (lathe, welding machine, etc.). I´m specially interested in the standby losses. I see you guys found an easy and cheap solution to lower them to some 20-25 w, but even that is a bit too much for me. I also have a Victron Phonenix 3000 that draws some 15W according to specs (never measured).
So, I was thinking, since the Victron is always on and the PowerJack would only be turned on manually or controlled by a timer, how do you see a relay replacing the ON-OFF switch? This way I could keep the losses at a minimum. Thing is, I do not know if there are any risks on doing so?
The idea is the same timer that controls the load controls the relay, so the load would be connected to the output and then the POwerJack would be initialized and start driving the motor.

Any ideas / recommendations welcome

Cheers,
Rob

[rossw]

and no jokes about my crappy scope

Heck no. I've still got my first ever CRO - a BWD539C. A little flasher than yours, but certainly doesn't hold a candle to my others nowdays. But was a great workhorse.

[oztules]

If you put the inductor in and use sleep, it will use next to nothing. It was supposed to use 25watts in sleep if you had the original 400w loss... with a 25-30 watt loss, that will drop down to insignificant I suspect.. never measured it that mode... never used that mode..

But a relay instead of the switch will do fine without any problem. It will start a full load from standstill without a flinch.

If your control device has a spare NO/NC contacts then no relay needed either.... just bypass the switch with that.

.............oztules

[off the wall]

Do I read the question about the relay differently?

Is the thought to move from one inverter to the other inverter? The issue there is that they are not phase locked so going from one to the other can give a voltage surge.

OZT - with your current work with the boards, the holy grail might be to be able to use one controller card for multiple power cards in multiple inverters

Best wishes

OTW

[oztules]

OTW... my experience with the victrons here  is that they are pretty wimpy with inductive loads.

 A 1500w induction motor with any load will generally stop them in their tracks....a 2kw motor probably won't start unloaded...... particularly if you have the house running as well. ( my PJ will easily start a 10hp 3phase motor used as a phase inverter.. no idea how it can either... in that configuration the start current must be immense )

So I expect the PJ will be used to drive the heavy intermittent loads on it's own AC circuit.

Stacking would be an interesting project, may be as simple as using the second and third in their UPS mode... there they sink with the main grid anyway... so you should be able to use the power from the "inputs" once the on board sync relay locks in... I wonder if it is that simple.

.......oztules

[off the wall]

Your comment about the PJ performance being superior to the Victron is interesting.

Certainly it's a pleasure to have been using the PJ without any glitch at all with any load and especially with the new power capacity arising from the stacked transformer. Many people find that it's the inverter that's their limitation and now with mine on 24V it's my busbars and connexions that prevent me being any more power greedy at this time.

It's on 48V that the opportunity for real power will happen and I'll need to find space for a new system.

I'm a little confused as my grid meter was changed around a year ago but doing readings the other day I think I have saved towards £3000 over the past year on grid electricity as a result of my grid-tie and offgrid systems so work on adaptation and improvement of these inverters is really worthwhile.

Best wishes

OTW

[oztules]

There are a lot of off grid systems over here.
My experience with them is limited really, but some things stand out.
Most of them use gas fridges, gas hot water, and if they give you a coffee they heat the water on the gas top.

They can't do the washing at the same time as vacuuming or anything else really.
They are all under paneled, and rely on their generators to do a lot of things because their pretty inverters won't run anything useful

When they come face to face with what mine does, they are truly blown away. there are a few folks with real inverters (generally in the 8000 to 10000 dollar range, that can do pretty nearly as much as me, but, they are terrified to really let them off their leash, in case they damage them.... and the remoteness of the place discourages this behavior.

The PJ is great for a lot of reasons, but ease of backup is probably the most important one here..... so easy to fix and replace the entire innards for peanuts compared to the other equipment.

From what I have observed, the victron gives reasonably  trouble free service..... but it is near useless for real living..... best for cave men with hardly any power use requirements.


................oztules

[andymack]

With my construction of the 6kVA toroid is on hold until I get back to Brissie.  I'm now at my alternate, very offgrid location watching the flood waters recede from last weeks downpour. 

Just installed the new un-modified PJ Lf8000 24v to replace a blown up chinese HF unit as our secondary unit.  It worked,  0.9amp idle (tick), however it trips out on over temp after 90 minutes of running the 1800W hot water.  I can live with that if it has no other sins.  Just let it cool down and run it again.  I haven't run it with higher loads yet. 

It's not running the house power, just HWS, transfer pumps, washing machine and a freezer.  Seems to be running well enough on standby.

Cheap grunt as a 2nd inverter ... so far 

[andymack]

Oztules

How things have changed .....

When we bought our offgrid property 8 years ago we were looking at $10 per watt for panels and many thousands for pure sine wave inverters so we were going to use LED lights, gas everything, super efficient appliances, and a lot of diesel.  We had a 2400 watt Modified sinewave inverter - failure rate of light bulbs and power supplies for laptops, modems etc was high.   The thought of running the electric jug for coffee, and electric HWS was crazy.   Still haven't built final house but with panels at less less than 1$ / watt we got the 10kW solar array, new  litium batteries, latronic 3kw PSW inverter and a second cheap 3kW HF inverter.

How things have changed - from then to now where I run the electric jug, Air conditioning - thank the gods, electric  hot water, pumping water all over the place - all solar.  The Generator gets a run maybe a dozen times a year, other than to run a compressor, welder or other serious tool.

Next year - we build and we'll go 48v and with the new 6kva inverter (x 2).  We only just realised that with the new inverters that we'll no longer have to turn a genie on just to cut some timber or do some welding or use the grinder.

Absolutely marvelous .....

[off the wall]

How things have changed .....

When we bought our offgrid property 8 years ago we were looking at  . . . .

How things have changed - from then to now where I run the . . .

Next year - we build and we'll go 48v and with the new 6kva inverter (x 2).  We only just realised that with the new inverters that we'll no longer have to turn a genie on just to cut some timber or do some welding or use the grinder.

Absolutely marvelous .....

Yes - it's for the prospect of this sort of freedom that PJ has enabled by breaking both the technological and price barriers that I have been enthusing for a long time about what these inverters can enable us to do for a long time that we never imagined possible before. And this thread and OZT's work in hacking them to be able to do way more than intended is groundbreaking in unleashing the possibilities. My advice is to go to the 8000 or 16000 units and put more transformers in to enable them to run cooler and don't economise on the 6000W unit. That unit might even only have one transformer with extra cooling. However, the cheap ones on ebay give a source of extra transformers cheaply.

Best wishes

Harem