My mistake was fatal to all 3 of my batteries by leaving them on a charger for months. They all swoll up so that insertion is not possible. I had been so busy that I forgot to turn it off. Anyway, I have 3 more on order and while awaiting I decided to tear one down. Not too hard. Also I found a video that describes the repair process. I can buy the replacement cell pack for $75 and have one on order. I do know that you have to maintain substitute power to the control circuit board during the whole process. Has anyone here successfuly repaired one?

I have not, but as the owner of an ungodly amount of m2 batteries, I am very interested in this process and what parts are needed to do this!

Hello there GaryDoug. I am sorry to read and to know about your DJI Mavic 2 Intelligent Flight Batteries and thank you for reaching out. Just a friendly reminder that the lifespan and condition of the said DJI batteries will depend on the totality of how it was used and stored. Hoping for your kind understanding that every electronic product and batteries has a certain warranty period and lifespan. For safety purposes please store and maintain the said batteries properly for you to be able to maximize the use of the said batteries. Just a reminder that using swollen, depleted or bloated batteries might lead to damaging of the aircraft, or worse, damage to property.  DJI do not recommend doing a DIY in fixing these DJI intelligent flight batteries to avoid any unwanted incident. Thank you.

TonyPHX Posted at 7-23 20:03
I have not, but as the owner of an ungodly amount of m2 batteries, I am very interested in this process and what parts are needed to do this!

As I am learning through first hand experience, this is a very difficult job. Mostly it is because the battery housing is very hard to disassemble because of the adhesives used. You have to pry off the top cover and while that is not extremely hard, it does invite risk to damage inside and if that severs the battery connection, the task fails because the controller senses the loss of power and shuts down the function permanently. All of this requires a dedicated effort to avoid that. It looks like a few folks on the web have figured it out. I am not one of very patient people....yet;-)

If you need to reset the BMS there's a way to do it with a cheap Cp2112 adapter,  here's as link to a video that explains it but you need to turn on English subtitles.  

DAFlys Posted at 7-24 00:07
If you need to reset the BMS there's a way to do it with a cheap Cp2112 adapter,  here's as link to a video that explains it but you need to turn on English subtitles.  https://www.youtube.com/watch?v=K3DrwyzjVvo

Thanks. Now I have the adapter on order.

Very keen on this, keep us posted.

It takes a long time to get the materials from China and I do not have much just yet. So I want to share what I know now. The cost of a new battery cell assembly is about $80 US. If you are not extremely careful in disassembling the battery, it will cost another $16 US to replace the case. It is very difficult to disassemble the battery without damage on the first try. You know the pitfalls only after the first try. There is a lot of strong adhesives inside that make it hard to remove the pack even after you separate the halves of the case. You will also need a device to reset the controller board in the battery because it will set a flag disabling the battery when you disconnect the cells. This device costs about $30 US but of course you only need to buy that once.
In short there is probably no reason to try a repair if the cost of a good used battery is about $150 or less.

Heat from a hair drier might soften the  glue.

Sean-bumble-bee Posted at 8-13 21:04
Heat from a hair drier might soften the  glue.

That's a good idea. I could save some muscle and frustration ;-) Still, I doubt it is worth the effort. I wish that I could say otherwise.

The battery replacement took about a month and the  cp112 board took 2 months. Am now ready to do battery rebuild. I will wait until it is a bit cooler. The batteries came with no charge so I am hoping they will charge when alll assembled and flags reset.

RK7dronzy Posted at 8-14 02:38
The battery replacement took about a month and the  cp112 board took 2 months. Am now ready to do battery rebuild. I will wait until it is a bit cooler. The batteries came with no charge so I am hoping they will charge when alll assembled and flags reset.

I am starting to believe it is a waste of time until the M2 batteries become impossible to buy. It takes more effort and expense to repair one than the price of a good used one right now. But if it comes necessary later, we could find this experience critical. I will also carry on.

GaryDoug Posted at 8-15 20:06
I am starting to believe it is a waste of time until the M2 batteries become impossible to buy. It takes more effort and expense to repair one than the price of a good used one right now. But if it comes necessary later, we could find this experience critical. I will also carry on.

I agree but the trouble with second hand batts is the amount of charges they have had and the type of use. I have bought a new batt off the dji store recently at £130 + so doing a diy rebuild at half the price seems worth a try. These mp2 batts seem to me to be rubbish when they are only good for 50 to 70 charges before swelling. I started with 3 batts which dji replaced but were just as bad, still i did get 150+ charges between the 2 lots.

GaryDoug Posted at 8-15 20:06
I am starting to believe it is a waste of time until the M2 batteries become impossible to buy. It takes more effort and expense to repair one than the price of a good used one right now. But if it comes necessary later, we could find this experience critical. I will also carry on.

An update to my fun with battery rebuild. Well as you can guess a failure. Getting the battery apart was not a problem apart from the first pack that i managed to ignite into a lovely ball of flames. The second pack i was more carefull and dissasembled without igniting. This is where the first problem comes when taking the board off the 4 batteries as the tabs are spot welded onto the board and removing damages the fine lines for the individual voltages. This means that even though there is 15.6 volts going to the BMS board it is dead without the individual voltages going to the bms board as well. I did test the battery and bms board before dismanteling with the SP2112 board attached to pc and it red all details in battery. At the moment i am stuffed because i cannot seem to find a battery connection board for sale anywhere. It was a learning exercise and i am not so frightenef of lipo batteries.

RK7dronzy Posted at 9-4 03:25
An update to my fun with battery rebuild. Well as you can guess a failure. Getting the battery apart was not a problem apart from the first pack that i managed to ignite into a lovely ball of flames. The second pack i was more carefull and dissasembled without igniting. This is where the first problem comes when taking the board off the 4 batteries as the tabs are spot welded onto the board and removing damages the fine lines for the individual voltages. This means that even though there is 15.6 volts going to the BMS board it is dead without the individual voltages going to the bms board as well. I did test the battery and bms board before dismanteling with the SP2112 board attached to pc and it red all details in battery. At the moment i am stuffed because i cannot seem to find a battery connection board for sale anywhere. It was a learning exercise and i am not so frightenef of lipo batteries.

I had the same experience. The circuit foils on the base board came off with the battery terminals. Oh well. I ordered the complete assembly for 3 times the price. Still not ready to proceed.

RK7dronzy Posted at 8-16 02:56
I agree but the trouble with second hand batts is the amount of charges they have had and the type of use. I have bought a new batt off the dji store recently at £130 + so doing a diy rebuild at half the price seems worth a try. These mp2 batts seem to me to be rubbish when they are only good for 50 to 70 charges before swelling. I started with 3 batts which dji replaced but were just as bad, still i did get 150+ charges between the 2 lots.

I've had 7 batteries all swell up and crack so they're unsafe to use.  None have over 40 cycles on them.

DJI Support have refused to replace any of them (just tried again this week and got told no).

gnirtS Posted at 9-6 04:01
I've had 7 batteries all swell up and crack so they're unsafe to use.  None have over 40 cycles on them.

DJI Support have refused to replace any of them (just tried again this week and got told no).

Thats bad my first 3 batts all swelled after 60 charges and dji replaced them with 3 of the same, but the one i recently bought is a IS 16046 (part 2) :2018/IEC 62133-2 :2017 whatever that means. That has only 10 charges so far but i have noticed that the cell voltages are all the same. I think that all the mavic 2 batts pre 2020 are all faulty and dji are not going to admit that in case of legal action. How many millions of batts out there waiting to fail or swell. Interestingly the manufacturer of dji batts allow for an 8% swelling and i think that the batts are the most expensive part of this drone over its lifetime. It is a pity that we cannot retro fit 4s or 6s batts that are more common and cheaper.