Phantom 3 RC LiPo battery repair

[JayW]

Hello Waylander;

I did some checks on the components on the PCB and I have the following as in the picture. There is a charging circuit and discharge circuit.


The circuit is pretty standard and similar circuit can also be found on online websites. What this means is that there is no smart switching circuit as far as I can tell from the PCB. Unless the IC marked CGGB is some form of FPGA which I doubt.

My cells still hold 4.2V each and can each be charged by the B6AC to full. So the cells are ok.

So that leads to only one conclusion is that one(or some) of the components on board is faulty and I suspect that one of the power mosfet (AO8810) has become open circuit.

I will try changing that and see if that revives the battery.

Just to add: the circuit s similar to this one here 6.4V 2S Protection Circuit Module/PCB for LiFePO4 Battery Packs

 

[Waylander]

Hello Waylander;

I did some checks on the components on the PCB and I have the following as in the picture. There is a charging circuit and discharge circuit.
View attachment 87914

The circuit is pretty standard and similar circuit can also be found on online websites. What this means is that there is no smart switching circuit as far as I can tell from the PCB. Unless the IC marked CGGB is some form of FPGA which I doubt.

My cells still hold 4.2V each and can each be charged by the B6AC to full. So the cells are ok.

So that leads to only one conclusion is that one(or some) of the components on board is faulty and I suspect that one of the power mosfet (AO8810) has become open circuit.

I will try changing that and see if that revives the battery.

Just to add: the circuit s similar to this one here 6.4V 2S Protection Circuit Module/PCB for LiFePO4 Battery Packs

Great Job JayW,
If I had the time back when I did the repair, I should have checked out the IC's and from that inferred what the circuit did, do you have access to an oscilloscope if so when you complete the repair it would be interesting to see the waveform of the current draw at switch On of the RC.

Please keep me and the forum informed of your good work
Ta-ta Waylander