What is the black board inside a Q500 Battery for?

[JanElze]

Now I have disassembled a Q500 battery and a Typhoon H battery . Both have protecting boards in.
Q500: DLX-690.
It is between balancer cable and battery. All wires are connected 1:1 except the 0V (ground). There is an MOSFET inbetween.
Usually those are protects all 3 cells against over-voltage and under-voltage. It's only the balancer cable, not the main power cables - no risk during flight.
View attachment 14709
I have testet this circuit, but it protects only against over-voltage. The MOSFET cuts the 0V balancer line at 4.22V. The charger will indentify this as error and stops charging.

The Typhoon H has a similar circuit for 4 cells. The switch is now at the red (+ 16V) line and consists of 2 p-channel MOSFETs AO4407 in parallel. This is the horizontal-pin.

View attachment 14708

I'm on to check if it protects only against over-voltage too (as Q500 batts) or if it is better and will also cut the line in case of under-voltage. DLX-6118:

View attachment 14706View attachment 14707

br HE

Hi , I'm having problems with my Yuneec H plus battery's, the circuit board has a problem with the red wire, there is a sort of fuse and there stops the voltage.
can i remove the board complete ??
and then still load on the yuneec loader ?

 

[WTFDproject]

Hi , I'm having problems with my Yuneec H plus battery's, the circuit board has a problem with the red wire, there is a sort of fuse and there stops the voltage.
can i remove the board complete ??
and then still load on the yuneec loader ?

It sounds like the safest thing is to dispose of that battery and replace it with a new one. If you are not extremely familiar with LiPo batteries the consequences and probability of a serious mishap far outweigh the cost of a new battery.