PowerJack smoked

[Pete]

Recently my 8000 LF powerjack emitted smoke. It turned out that it had blown up the Mosfet boards and the driver board.
Actually two of the Mosfet boards looked fine but I replaced them anyway.
What appears to have caused the blowup is that I had mounted the inverter on its side so that I could see the screen.
The Transformer has been affected by gravity and with the windings touching the case it has worn through some varnish on the windings and shorted to the case.
At first I thought that the blowup was caused by my circular saw jamming and that the inverter had overloaded. It has done this many times, but all those other times it just screamed and needed to be turned off and back on.
This time there was a voice from inside.
 the inverter telling me that it had problems.
When I was disconnecting the inverter I got a slight shock from the case. Strange because I have an earth wire on the case but of course with a 200 amp fuse protecting the inverter it takes a big short to blow the fuses. My system is a 24 volt system
Anyway after waiting in these new slow delivery times for parts I replaced the mosfet and driver boards and it is alive again.
Just thought that I would warn anyone with a Powerjack not to mount it on its side.
Hope everyone is well out there
Pete

[dochubert]

Hi Pete,
Sorry to hear your pj blew up.  As to mounting on the side, I remember someone on this forum hanging the transformer on a leather strap through the center hole.  Got good airflow that way and didn't have any metal close to the windings.
(Might be easier to just lay it flat.)
Glad its back up and running.

[Pete]

Thanks Doc, yep I just laid it flat this time. Been running well now for a few days. One day I will get around to trying to fix the old boards, I have new mosfets and surface mount transistors, but playing with surface mount stuff is not fun. May be ok if you are 20 years old with perfect eyesight but even then I don't think I would like it.
Cheers
Pete

[lighthunter]

quote "The Transformer has been affected by gravity and with the windings touching the case it has worn through some varnish on the windings and shorted to the case. "

Wow, thats too bad. I was thinking the transformers
had a rubber pad on top and bottom with square plate over
each end with bolt securing them tight. My memory is bad tho and i never had an 8k only 6k's. The way mine has been assembled for years now is two of the original transformers stacked and another secondary wound around the whole thing then the stack is rotated 90 deg so the fan blows through the hole. The covers are squeezing the transformers tight to hold in place ( the covers have an inch gap because of thickness) more air venting Ha! I dont recall what i put between aluminum and the windings. Im thinkin i put rubber but i better check. Thanks Pete!

Good to see you moved up to LFP Dochubert! I have only 200AH lfp @ 48v and still using the 540AH 48v traction. It had decreased in capacity to about 180AH with high self discharge and low voltage, in fact would boil violently at 56v. I put in 3oz/cell battery equaliser 6 months ago and now capacity is 275AH and i saw it floating at 55v and 2.75amps a couple days ago. I realize additives are very controversial. This one responded well but you always have to consider you couldve spent the $150 towards new batteries too.

LH

[dochubert]

Good to see you moved up to LFP Dochubert!

Great to hear from you LH!  Been too long!
Yes I made the switch when my sla batteries started failing at 3 years of use.  Very happy so far and about to double the size of my main 48v lifepo4 bank.
So you used the chemical additive on your forklift battery? I've always wondered if that really worked.
Looking forward to some new posts about what you've been doing!