y Philippines Retirement Solar Off Grid System

[rossw]

I wonder if something like this would help?

https://www.flippers.com/pdfs/k7205.pdf

[lighthunter]

Testing a transformer is very straight forward and easy. I would not recommend an ohm test of winding as it would require extreme accuracy to detect a shorted turn in a kw size like you have.

1. Does it smell bad or any unusual odor? If so, its bad or will fail soon.

2. If you can do a megohm insulation measurement that can flag a winding insulation fail to core material.

3. Most important test. Disconnect primary and secondary from inverter. Safety first Connect fused line lead of grid supply to one terminal of say 500w halogen lamp, the other lead of halogen lamp to one lead of transformer secondary (230v side) then connect the remaining transformer secondary lead back to the neutral grid terminal. Make sure the voltage of halogen is same as grid supply volts.

 What you are doing is powering up your transformer with the grid. The halogen will absorb the high start current when you plug it in. If the light burns brightly, the transformer is bad. If the light flashes and then glows dimly the transformer is good. Next measure the current and voltage at the secondary terminals. You should get very near mains voltage and under 1/4 amp. The primary volts should measure 25-30vAC if its a 48v inverter. Ive not looked at Ross's link maybe covers this better than ive written it. My thoughts on transformer being bad are very unlikely transformer got hurt. Normally the fets and fuses will burn very fast and never hurt a transformer that size but i suppose anything is possible. My guess is your main board is not seeing the feedback voltage so its ramping up to attain it (why you are seeing >230) and then the software times out and shuts down from no feedback to protect itself.

I didnt read much detail so if you already checked this stuff please ignore.

[solarnewbee]

Thanks guys

Probably try voltage test first. Engineer at Powerjack sent a video showing applying 120v to l1 and neutral secondary  and checking for 30vac at primary. Primary has 2  red and black so assuming red and black comprise a winding each.

I noticed when communicating with Helen at Powerjack that using simplified English gets better results. I asked for help 3 different ways before I got a answer on the transformer.

[rossw]

Probably try voltage test first. Engineer at Powerjack sent a video showing applying 120v to l1 and neutral secondary

As mentioned, DO use a current limiting device like a decent lamp, because if there IS a shorted turn, it could get very hot, very quickly.

[solarnewbee]

You’ll be happy to know the transformer is fine. Got 22v out which is kinda low but then I find out my step down transformer is only giving out 104v. Someone wound that one wrong.

Now all I get is a few pulses out from the transformer and then alarm and a brief 250v. All 8 fet boards working this time. I think Helen sent me 4 bad fets and a bad LF or driver board. Temptation wants me to put my repaired board back in and have a go but with the replacement driver. If I understand Pete correctly a bad driver will blow fets every time.


Wait and see

[Pete]

You could put a resistor in series with the DC supply to the inverter.
That way you can swap the boards over and have much less chance of blowing the inverter up.
I did that when I fixed my inverter, I think I started with 20 ohms, then down to 10 and then down to 5 ohms.
If you run the boards without the transformer connected then you can use a scope ( if you have one) to look at the output of the driver board, and also what the drive to the mosfets looks like.
It is a lot safer that way , you can make sure that each mosfet is actually getting a gate drive and that all the resistors around the mosfets are good before you connect the transformer.
Pete

[lighthunter]

Pete has lots of great info there.

I think you have a newer powerjack than ive had experience with but some of the design would be similar.

1. If you power on and you see AC voltage at output ramp up and exceed setpoint without any smoke, you have an inverter thats 90% working. Its impossible to get that behavior if even 1 mosfet or drive is not correct.

Im not sure which version (year) yours was made but if the feedback polarity were switched somehow it could cause the behavior. Double check the connections.
It sure seems like V feedback is missing.

[noneyabussiness]

if you remove the large capacitors snd put a 10 ohm resistor in series with the power supply,  you won't lose any mosfets during testing... its mainly the caps that blow em ..very well documented in Oz's thread..

[Pete]

Hi Noneya, oops I forgot to mention those capacitors. Glad you came in on this one. They hold a fair whack of charge and can easily do damage if unleashed on a poor mosfet.
I unsoldered mine with a very old soldering iron, it is basically just a large lump of copper on a handle. Heat it up with a gas torch and it can undo most joints. I just heated the solder up and lifted the caps out. Then re drilled the holes for the legs when I put them back in.
Cheers
Pete

[Pete]

Hello Solar, well on the subject of PowerJack inverters, my 8kw 24 volt inverter blew up yesterday.
I pulled it apart and yep the AC mosfets were toast, and the Optocouplers on the driver boards were seriously discoloured.
I had a couple of spare boards and a spare driver board so fitted them.
One of the mosfets blew almost straight away. They are cheap Hy4008 mosfets, so I am hoping it was just a faulty one.
While looking carefully at the inverter something I noticed was that the negative cables to the power board were all fused together at the input terminal. They had got so hot that the pvc insulation on them had fused.
I had to actually cut the cables to remove the input terminal. The screw that held the lugs on was a phillips head type and it was totally siezed in. I ended up having to drill it out and re tap the hole.
I am now thinking that a bad connection on the 24 volt side is most likely the cause of the two blowups this inverter has suffered.
So I will repair that and also put a new allen head screw on the positive side too.
I have one of those aliexpress 5kw boards running the house at the moment, so if the powerjack is completely dead I will fit an 8010 based board to the transformer and junk the powerjack boards.
Just thought that it may be worth you checking the connections on the low voltage side while you are trying to fix your inverter
Pete

[solarnewbee]

I have a desoldering gun, just bought recently after I plugged the old 110v one into 220v doh! Anyway LH it does sound like it’s a feedback problem. I don’t remember what they call the board but it says ac charger board, lcd plugs in there and transformer connects there. A ribbon cable runs from there to the LF board and I’m sure one of those is a feedback signal. They should have given me a cable to plug in since the replacement actually has a connector on the LF board. The old board had the wires soldered in various places to 1. Obtain 12vdc for the lcd’s. 2 assuming feedback 3. Watts limiting Powerjack gave me a pic of wiring on the connector but it did nothing. Grey and white wire both looked white and took quite some doing to get them to clarify. Then the inverter did nothing, so I wired it like the old board and it came to partial life.

My inverter is a 2019 black with the stamped out lettering rather than decals. Version 10.3.1 LF board with driver board plugged in and screwed down.

I ordered a 9kw that’s within my budget and really 15kW was over-kill anyway. Helen asked me about max wattage I would be using and I told her maybe upwards of 8kw when welding and she tried to sell me a 15kW. I asked why and she said they limit the watts in software to 5.8kw due to transformer cooling. I talked her into having them raise it after describing my cooling mod. My mod is modeled after dochubert’s. I remove the clamp and raise the transformer up on rubber blocks and place a fan on top with rubber blocks and the fans on the sides. Works beautifully. Temp sensors glued to the coil for variable speed control. Cheap fan controllers from aliexpress have never failed, yet.

I’m gonna keep trying to repair the 15kW but I need an inverter now and also a break from the frustration take a step and consume you guys recommendations.

[solarnewbee]

Sorry to here that Pete. I had my power boards out recently checking them and the low side connections looked good and were tight. My 1/4” impact had a fight getting them off.

Best of luck

[solarnewbee]

New inverter on the way and hearing talk about 8010 boards. I see them on shoppee.com individually and on sunyima inverter boards. Question is, is there a way to wire an 8010 to a Powerjack power board like my repaired ones. I would have to trace out the ribbon cable to tracings.

If I remember correctly all the drains?, are tied to the heat sink (positive) and source tied to negative npn fets. That leaves the gate trigger lines and which ones are which?.  Gates all have that 47r resistor that blows when the fet does. Must be a blast of energy thru the gate to the resistor straight to the LF and driver board. Correct me if I’m wrong please. Others may learn too. Oz probably knows/knew all the ins and outs of Powerjack but I don’t think he’s messes with them anymore. Hope he’s ok he kinda disappeared from the scene.

[Pete]

Hi Solar, there should be lots here by Oz about the 8010  boards. I am sure he was using the powerjack mosfet boards and driving them with the 8010 chip.
Otherwise just get a complete 8010 based inverter board ( I have both 3kw and 5kw boards and am using powerjack transformers)
I think the Big Oz inverter used an 8010 chip to drive it.
Clockman would be the one to talk to about them, he does plans, boards and a book on them.
Cheers
Pete

[solarnewbee]

Hey Pete found that thread. Oztules built a board and placed a 8010 chip on a pcb board. First glance looked like a nano ha. There are boards out there that have the outputs that I see going to the gates and source or drains on the power board. I can imagine tracing out the Powerjack boards and connecting the egs-002/8010 board to it. I have a male connector to fit the ribbon cable I took off the LF board. All this when I have nothing else to do.

My Sunyima inverter board came in before my powerjack 9kw. It sold as a 190a 24 mosfet unit. I connected it to my old 15kW transformer and got 201v. They recommended a 26v coil but upon looking at adjustments in settings(it came with an lcd) I found voltage output. Ran it up to match grid. Quiet very quiet. Old PJ transformer was loud just idling but with this Sunyima attached it is completely quiet. Setting let’s you set low voltage protect and high voltage protect. That is if you get to setting fast enough before the screen whites out.

Pic of unit installed and the wiring diagram seller provides in the advertisement. Seller doesn’t respond at all so the problem with the lcd will probably not get solved.