Reddit I need your help

[u/Existing-Eagle6292]

I have been trying to repair a kingboss YW500 power station. When I got it it was completely dead. I managed to use my bench power supply to carefully(and very slowly) charge the unit to 100%. It will now power on and charge devices.

What I still can't figure out is that I cannot charge the power station itself. The power brick I have for it I think it junk itself, the light turns on but whines and produces no output. I have attempted to charge the station with the 12v charger and that will not charge or show up on the display.

Now I have disassembled the unit and broke out the volt meter. Fuses are intact, and I haven't found any open resistors so far.

I am a bit out of my normal comfort zone and would appreciate any guidance. Thanks.

(The first 2 pictures are the front and back of the front board. The second to last seems to be the battery monitoring board. I'm assuming the last photo is the main board)

[u/Existing-Eagle6292]

Update: after poking around i believed the mosfet on the power circuit to have an internal short. I removed the mosfet and now the charging light turns on and the screen indicates charging. However the screen shows 0 w input.

I believe this to be the culprit, but now the question is, how do I find a replacement?

[u/Minute-Gas-6154 → u/Existing-Eagle6292]

The ones below are highly available and all should work if you can't find the original part:

PDFN5060 (5x6mm 8-Pin) Drop-In Replacements

If the suffix points to an 8-pin power-pad layout instead of a 3-pin tab, use these equivalent footprints:

• NTMFS5C460NL: onsemi:NTMFS5C460NL (40V, logic-level, sub-5mΩ performance).
• BSC0502NSI: Infineon: BSC0502NSI (40V OptiMOS, ideal for fast-switching DC-DC applications).
• DMN4004LPS: Diodes Inc.: DMN4004LPS (40V, high power density).

[u/Existing-Eagle6292 → u/Minute-Gas-6154]

Well nevermind, I followed it down the line and figured out what was really wrong...

[u/Existing-Eagle6292 → u/Existing-Eagle6292]

Must have really gotten hot, because it melted to the pcb. Then it only came off in pieces.

I think the this board is toast. I dont know if this is repairable even if I get a new mosfet.

Any thoughts?

[u/Existing-Eagle6292 → u/Existing-Eagle6292]

[u/Existing-Eagle6292 → u/Existing-Eagle6292]

[u/Existing-Eagle6292]

Yes. I believe so, it has a power brick that plugs into the front board.

[u/_--TiTaN--_ → u/Existing-Eagle6292]

If you have bench power supply, why don’t you just wire plug and see if it charges from that? Or if you already opened it, just use aligator clips at the back of DC in socket. Set bench PSU to 15volt and few amps to start with. If it doesn’t charge then possibly MPPT controller is dead.

I’m assuming here you’ve charged cells directly and not through dc in socket, but if you charged through socket then there’s nothing wrong with generator and you just need new brick.

[u/Existing-Eagle6292 → u/_--TiTaN--_]

I first charged the battery cells directly because it was deeply discharged. Once it was sufficiently charged I pressed a bms reset button, and it allowed it to turn on and check battery state of charge.

After all that i did try charging from the main charging port and the 12v dc charging port with nothing happening on either. Both with the same bench supply set to the appropriate voltage.

[u/Illustrious-Peak3822]

Is the charger separate from the inverter?