Pylontech US3000A PSU board

I see 2 resistors on the PSU board for my other battery fried. I’m looking for a damaged pylontech battery around Joburg… thanks.

Those look like the gate resistor for the balance circuit. If they are blown, I would bet that is not where the problem ends - you are probably going to end up replacing both boards. The discoloration on the leads of what I assume is a balance resistor indicates that the attached cell might also have been over-discharged.

8 MOSFET are short

I moved the cells into the other case and they seem to be charging ok.

What happened to this unit? Surge/lightning?

I suspect surge.
I’ll replace the MOSFETs and see what happens…

I think all 9 of those FETs are in parallel (just check), so you could remove the dead 8 and test, as long as you keep the load below 1/9 of the rating. 9 of the 18 would be charge disconnect and the other 9 would be discharge disconnect - so if they failed in a short the battery would still be usable, but not fully protected anymore.

I don’t really want to dampen your spirit, but if R144 is dead, Q122 is also dead, and probably also the micro that was on the other end of R144. (working on assumptions based on the limited part of the circuit I am looking at).

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R144 is labeled 5100 which is a 510ohm, correct?
I read 509ohm with my multimeter. The other resistors read 511ohm, 512ohm etc. Does it mean R144 is dead?
I’m looking for a replacement board but will play with this one so long…

Hardly! There are always tolerances, usually around 1% these days. So that resistor can be 5Ω off and it’d still be perfectly fine. In fact, I rather doubt your multimeter is even that accurate. It is definitely not dead if it reads 509!

Agreed. I only assumed it was dead because that is stated in the OP.

Thank you both.
The FETs are not available at any of the stores around Joburg. I am also not sure I’ll be able to manage the load below 1/9 the rating if i take out the 8. I am looking for a replacement board…a second hand from damage module will do

65A @100V

This is the mosfet you are looking for:

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Thank you for clarifying. I almost ordered STF150N10F7 which is 65A.

STP150N10F7AG is available on RS component in EU…4 to 5 working days.