Mavic Pro Factory Battery Controller Mod

[Mechcondrid]

ok so obviously the mavic bat control board is way more advanced than your standard laptop pack; i need a real clear pic of all the chip's faces with markings as visible as possible so i can identify what each chip is, the big 4 pin chips near the back (i think? may be the front when looking down on them) are either fets of some kind or possibly solid-state relays (leaning towards fets) which would be how the battery controls the power on of the drone and supplying the power to the ESCs

my big interest is the MCU chips and anything around it (them) as if it will brick itself on a catastrophic cell state (too deep of a discharge or overvoltage/current) then there must be a MCU on there running active code and a sanity check of some kind against a pre-programed standard which may limit what can be done before triggering error ouputs

may end up reverse engineering the comms protocols for the board and making a knock off with my own code if it turns out to be too inflexible

 

[lolo780]

If the DJI battery proves difficult, consider opening one of the knock offs.

Intelligent Flight Battery 3830mAh For DJI Mavic Pro Flight Time 27 Minutes OE | eBay

 

[Mechcondrid]

If the DJI battery proves difficult, consider opening one of the knock offs.

Intelligent Flight Battery 3830mAh For DJI Mavic Pro Flight Time 27 Minutes OE | eBay

well at this point its just down to what the stock code will allow, i can bypass and hack the hardware all day long but if i wanted to reinvent the wheel etc etc.
i'd idealy like to add as little hardware as possible to reduce end weight addition and keep from adding additional possible points of failure

 

[beanbubba]

well at this point its just down to what the stock code will allow, i can bypass and hack the hardware all day long but if i wanted to reinvent the wheel etc etc.
i'd idealy like to add as little hardware as possible to reduce end weight addition and keep from adding additional possible points of failure

If you can figure this out and how to predictably use the balance leads, you would be my new hero.

This opens up a whole new area of external battery monitoring that many devoted enthusiasts are eagerly awaiting a solution. You have my full and undivided attention and I humbly await your expert engineering solution to the problem.

 

[beanbubba]

I want to pull my hair out !!!

I had already given up on the battery controller mod, but I have a couple batteries that I only removed the case then insulated and didn't touch or mess with the electronics/wiring.

During typical flying activities I accidentally touched the backside of the controller leads to something conductive for a brief micro moment and bricked the controller. The tolerances on these darned battery controllers is so small that if you do this procedure to remove the case, make sure you cover up all possible areas that can short with tape or whatever your preferred material.

Geeeezzzz....

 

[chazz]

Sorry i couldn't help you with this. The top pic is one that worked and the bottom one is someone's that didn't. There are differences in some boards so maybe you can find one like the top one.

 

[beanbubba]

Sorry i couldn't help you with this. The top pic is one that worked and the bottom one is someone's that didn't. There are differences in some boards so maybe you can find one like the top one.


View attachment 28499 View attachment 28500

Chazz, thanks for sharing. Sorry but I am not following your description, can you please elaborate? Also can you describe your wiring setup in that picture and also tell us how you use it?

 

[Mechcondrid]

Chazz, thanks for sharing. Sorry but I am not following your description, can you please elaborate? Also can you describe your wiring setup in that picture and also tell us how you use it?

i think he is just uploading the pics for reference and if we possibly need it.

that 1000/101 part is a 100 ohm resistor, 1000 is the same smd resistor code wise as 101 so they probably just switched suppliers or had a part shortage with the original supplier and used a comparable part.

really wish someone could get some good high def pics of the board and upload them, i dont have the money to buy another batt right now as i'm in the middle of trying to fix my car to get it trade in ready so funds are tight for the next few weeks else i would buy a couple knock offs to mess about with.

 

[chazz]

Yeah i didn't know they were the same resistor but i saw they were different so i noted it also there is something on the board (don't know what it is) that is in a different position on the pictures the one with the arrow. I don't really know if that means anything just showing they are different.. This is the best picture i can give you.

 

[Mechcondrid]

Yeah i didn't know they were the same resistor but i saw they were different so i noted it also there is something on the board (don't know what it is) that is in a different position on the pictures the one with the arrow. I don't really know if that means anything just showing they are different.. This is the best picture i can give you.View attachment 28567

well i think that the tsop chip (the rectangle one) near the mcu chip on the bottom left of the pic is the eeprom so i may be able to interrogate it with a programmer or usb to serial converter

 

[beanbubba]

I placed all my bricked controllers in order left to right. My first bricked one was shipped to chaazz and he has that one. Interesting observation, the only 2 units I had any measure of success were the first 2 and they have a blue protective coating on the board. All the rest of them without the blue coating, I had very very little success (like one or two flights).

 

[beanbubba]

I placed all my bricked controllers in order left to right. My first bricked one was shipped to chaazz and he has that one. Interesting observation, the only 2 units I had any measure of success were the first 2 and they have a blue protective coating on the board. All the rest of them without the blue coating, I had very very little success (like one or two flights).
View attachment 28575

I hope @Mechcondrid can reverse engineer these controllers so I can recover them and hope they can fly one day in the future!!

 

[Mechcondrid]

I hope @Mechcondrid can reverse engineer these controllers so I can recover them and hope they can fly one day in the future!!

hey if you can gimme a close up of the tsop chip on the second board, i can see writing but cant make it out if i can grab a model i can grab the spec sheet and get a protocol definition for talking to it

 

[chazz]

The top one is beans board that didnt work the bottom one is one that did work

 

[beanbubba]

hey if you can gimme a close up of the tsop chip on the second board, i can see writing but cant make it out if i can grab a model i can grab the spec sheet and get a protocol definition for talking to it

Let me know if this image if good enough. I can also ship you a couple of these if you want them to test on. Private message me your shipping info if you want them. I also highlighted the pinouts that should save you some research.

 

[Mechcondrid]

Let me know if this image if good enough. I can also ship you a couple of these if you want them to test on. Private message me your shipping info if you want them. I also highlighted the pinouts that should save you some research.

View attachment 28583

that pic is good, that tsop is a texas instruments chip can see the faded logo, will have to search for which specific one; at work atm so cant really spend that kind of time looking.
if you can send me the one in this pic that would help quite a bit.
i think the square chip is indeed an atmel MCU but i cant really make out the lettering completely; it may also be a microchip brand MCU; i can make out what i think is msp on the first line there but the rest is not really clear.

i'll pm you my address

 

[beanbubba]

that pic is good, that tsop is a texas instruments chip can see the faded logo, will have to search for which specific one; at work atm so cant really spend that kind of time looking.
if you can send me the one in this pic that would help quite a bit.
i think the square chip is indeed an atmel MCU but i cant really make out the lettering completely; it may also be a microchip brand MCU; i can make out what i think is msp on the first line there but the rest is not really clear.

i'll pm you my address

Just curious, why did you focus in on this single board out of the group?

 

[Mechcondrid]

Just curious, why did you focus in on this single board out of the group?

no blue resin coat and i could see even from the farther picture that the chip im most interested in (eeprom storage) has pretty clear markings so best chance of getting in to see the stored settings and code.
the mcu is secondary as i mainly want to alter mah settings and the like and the most likely place that's stored is in the eeprom since that is almost always a non-volatile storage medium where the non-volatile storage that is on board the MCU is limited in space and usually isnt used for much beyond program storage and bootloader settings for firmware updates

 

[Mechcondrid]

also thanks for that pic marking the serial links, that'll let me do some sniffing to get what commands are being send and received; that's gonna be a big jump in getting the mavic to accept any aftermarket mods on the power side since then i can spoof the output to what the mavic expects the responses to be so no batt errors.

 

[Mechcondrid]

btw if anyone wishes to try and remove the blue coating on their boards this is a pretty good source of info; obviously if your not comfortable with caustics then dont attempt.

Coating Removal, Identification of Coating - Basic Circuit Board Repair Procedures