Here are the pinouts of the Mavic Pro battery

[cnd]

Not sure why no place on google or elsewhere here has this info easy to find... so I eventually found it here:-

WM220 Battery Intelligent Board

Tools for handling firmwares of DJI products, with focus on quadcopters. - o-gs/dji-firmware-tools

github.com

Here is the connector pinout:

Pin	Function
1	RXD (UART receive)
2	PACK- (GND)
3	PACK- (GND)
4	PACK+ (12.92V)
5	PACK+ (12.92V)
6	PACK+ (12.92V)
7	PACK+ (12.92V)
8	PACK- (GND)
9	PACK- (GND)
10	TXD (UART transmit)

As well as the meaning of all the pads on the back (not all board have these pads labelled - mine for example does not).




The SCL and SDA are especially useful - needed to reset the permeant failure flag using GitHub - o-gs/dji-firmware-tools: Tools for handling firmwares of DJI products, with focus on quadcopters.

 

[t0m541]

As a matter of interest, has anyone tried the reset point to see whether it actually does reset the board.
It'd certainly be a bonus if it does, it could have a microswitch wired into it that can be fixed outside the case for future any future issues.

 

[mjnhchj]

Not sure why no place on google or elsewhere here has this info easy to find... so I eventually found it here:-

WM220 Battery Intelligent Board

Tools for handling firmwares of DJI products, with focus on quadcopters. - o-gs/dji-firmware-tools

github.com

Here is the connector pinout:

Pin	Function
1	RXD (UART receive)
2	PACK- (GND)
3	PACK- (GND)
4	PACK+ (12.92V)
5	PACK+ (12.92V)
6	PACK+ (12.92V)
7	PACK+ (12.92V)
8	PACK- (GND)
9	PACK- (GND)
10	TXD (UART transmit)

As well as the meaning of all the pads on the back (not all board have these pads labelled - mine for example does not).


View attachment 136198

The SCL and SDA are especially useful - needed to reset the permeant failure flag using GitHub - o-gs/dji-firmware-tools: Tools for handling firmwares of DJI products, with focus on quadcopters.

Can this tool be used to unlock the battery after replacing the cell?

 

[michaelmcnally]

Not sure why no place on google or elsewhere here has this info easy to find... so I eventually found it here:-

WM220 Battery Intelligent Board

Tools for handling firmwares of DJI products, with focus on quadcopters. - o-gs/dji-firmware-tools

github.com

Here is the connector pinout:

Pin	Function
1	RXD (UART receive)
2	PACK- (GND)
3	PACK- (GND)
4	PACK+ (12.92V)
5	PACK+ (12.92V)
6	PACK+ (12.92V)
7	PACK+ (12.92V)
8	PACK- (GND)
9	PACK- (GND)
10	TXD (UART transmit)

As well as the meaning of all the pads on the back (not all board have these pads labelled - mine for example does not).


View attachment 136198

The SCL and SDA are especially useful - needed to reset the permeant failure flag using GitHub - o-gs/dji-firmware-tools: Tools for handling firmwares of DJI products, with focus on quadcopters.

So I need to solder to SCL and SDA test points so I can wire them to the CP2112? I tried this and could not get it to work. Not sure if I a) did not fully understand what you were saying b) i made a wiring error - i triple checked c) the battery/board are fried. Any advice?

 

[Harald]

So I need to solder to SCL and SDA test points so I can wire them to the CP2112? I tried this and could not get it to work. Not sure if I a) did not fully understand what you were saying b) i made a wiring error - i triple checked c) the battery/board are fried. Any advice?

I soldered two wires to SCL and SDA, and connected it to both an arduino UNO and an arduino Nano, on their respective SDA an SCL pins. Both arduinos work with the software from circuitschools.com.
However, I haven't yet been able to reset the batteries with the mentioned software, but it talks to the battery and comes up with all info about the battery.
The battery has to be turned on for it to communicate with the arduinos, which in my case meant that I had to open the battery and charge it with a bench powersupply I have.

When I try to do the unlock function on the software I get "unknown error"..
Any ideas, anyone?

 

[Exphantomflyer]

I soldered two wires to SCL and SDA, and connected it to both an arduino UNO and an arduino Nano, on their respective SDA an SCL pins. Both arduinos work with the software from circuitschools.com.
However, I haven't yet been able to reset the batteries with the mentioned software, but it talks to the battery and comes up with all info about the battery.
The battery has to be turned on for it to communicate with the arduinos, which in my case meant that I had to open the battery and charge it with a bench powersupply I have.

When I try to do the unlock function on the software I get "unknown error"..
Any ideas, anyone?

My guess is you arent using the right type of board the aforementioned CP2112 board is the one used by everyone to do a battery reset using the batterykiller software (google gets you the software), you only need 3 wires SDA SCL and ground although sometimes you need to supply power to the battery for the BMS to talk to the board.

As a side note its a pity that you have to open the battery to connect to the SDA SCL pads unlike all new ones that are on the actual battery connector, its why i wont do a repair on them to messy to open the case without damage, although i did see a YT vid of a guy who had a Jig that held the battery and 2 long pins that he passed through the case to connect to the pads, sadly i cant find the video now