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open mavic 2 battery

i was looking at purchasing extra batteries and noticed that this "seller" on taobao, china's ebay selling "upgraded" batteries that can fly 14kms with 16mins spare.

will be ordering one unit later to test it try it out.



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Thanks to your pictures, I am kind of thinking of just cutting a few peep holes into the casing just to see inside for piece of mind. That being said, I have used the battery several times now without issue... I made sure it was as dry as possible before putting it on the charger, which charged it without any issue. I then did a couple of "flights" where I just left the drone hovering over some pillows at a couple of feet, running the battery down to 15 percent or so... No issues. I then took another flight where I took it up into the air just around my house for a bit and ran the battery down again. Since then, I have flown a full charge on it several times without any issues.

...Hall monitoring, condescension and negative comments aside, I am happy to have gotten an extra battery out of this whole debacle.
 
I'm with you my friend. I had water damage and I'm sure parts of the battery can be salvaged. I have already dismantled 2 Mavic 1 batteries and rebuilt them into a 3s2p configuration. Works really well.

I have the two halves of the shell open, but it's difficult to separate the top and bottom of the cells from the case. Will have to carefully cut away more of the plastic to see what's holding the cells. I'll let you know when I've made more progress. The ultimate aim is to construct a long-distance battery as for the Mavic 1.
You rebuilt those batteries in 3S2P ? Was there any issue with the BMS noticing that the cell capacity changed suddenly ? Did you increase cell capacity ? I'm interested in testing that on M2Pro batteries. That would be great to keep a BMS and attach 4S packs to it. You can probably build 5 packs with high quality 21700 cells for the price of a single battery !
 
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Thank you all for posting this topic! So I am curious on the side of the battery puffing on the bottom of mavic 2 pro battery and I'm curious if there's possibly enough space there maybe put a little cut in there without cutting the battery?
I've been working with two batteries that started puffing for no reason. My other batteries are fine. but it feels like there's a pretty good Gap behind that bottom plate and any contact to the battery. So maybe a little expansion joint at the bottom might help this. I am believing it is more of a distortion of the plastic on the bottom then it is the actual battery pushing on it.
 
I took mine apart. In my case the thermistor wires broke off the BMS board. I had no issues removing the screws holding down the connector. Besides the screws, the connector latches onto the shell on the back side so that's why you have to spudge it loose.

I started from a corner and used an old credit card to break the seams free. No shell plastic damage, though the clips bent a bit. Thin layer of glue on the seams on flat sides, back and front. No glue in corners.

They use sticky double sided tape to hold the battery to the shell halves. The top and bottom cells partially separated from their neighbors (but not from the battery board when I tried to pull the shell halves free so that gave me more access. I did manage to break free the bottom battery from the shell but it was risky. If it weren't for the batteries, I'd say heat it up like you do for phone screens.

I successfully pulled free the ribbon cable from the BMS board so I didn't have to remove the led board and cut the latch sense wires. I eventually will check if those sensors are closed or opened when latched. I'm suspecting open and both strung in series where both latches have to be out of position in order to complete the circuit. If the latches are not independently sensed, then a firmware update can't be used to warn of a single latch out of place.

As for the thermistor, is that a plug at the battery side of the wire or the thermistor itself?
 
Answered my question about the thermistor. It's secured to the corner of the top battery with silicon adhesive. I managed to solder the leads back on, now it powers up properly. With thermistor disconnected, Battery status shows 1 LED on right, when powering on it brings up all 4 LEDs, goes dark, then the 1 LED.

Now I broke the leads to the latch senor. That would be tough to fix. There's a blue coating over the solder pad and it's tiny.
 
So with the latch switches disconnected, I carefully tested the battery in the AC, and checked status. App said cannot fly, Battery not properly installed. So the switch contacts make when latched, break when pushed in.

Knowing now how the latches interact with the sensing switches, I put a good battery in, pressed in one latch button at a time. Only with one, I get the battery error.

However if I rock one side of the battery up, I don't get a warning. It seems the latch doesn't get pushed in far enough to break the switch connection. If both latches aren't all the way, then it reports a problem.

So if the spring is stronger, it holds the battery in place better, but latch sense is not as sensitive. If spring is weaker, then likely it will better sense a latch not engaged.
 
The potential problem is not the corrosion you can see, it’s the corrosion you can’t see.
 
I had a phantom 2 battery that puffed up and was a bugger to install and remove from the bird so I decided to test how bad a lipo fire would be . I placed it in the middle of my yard and stabbed it with a sharpened rod . I would not want a lipo battery to fail inside a house . Flames were very small but the amount of smoke was crazy from one drone battery . There was the same amount of smoke as if I was burning a tire . Crazy . My battery’s don’t live in my house anymore. They are in a ammo can and in the garage . My guess is the smoke would be very toxic .
I have fire bags for mine and use them all the time, I teach skydiving and people make fun of me cause I hate commercial flights, but I tell them A) I have no exit plan from a 500 mph plane and B) do you realize how many lipo Batteries are in people's luggage waiting to take a plane down??? I personally know of two people who had black charred items in their luggage. Scary...

I would not keep that battery in my home, I would definently get a good FP bag for it, and then put that in a metal tool box or ammo can, I have one that took a drop and part of the seam is slightly open and I don't have much fear of it, but if it had been in water I would probably recycle it, I had a dewalt battery that fell in a bucket of water, all seemed fine for a while then one day it started smoking and quit working, a bit scary, hence why I now have snaps caps for the tool batteries and bags for the drone batts.
 
If it were fresh water and a normal lipo Id have no frets about using it but seeing as its encased and has a brain Id never think to put it back in my Mavic. BUt Id still take it apart, curious whats in there? Then short it out and watch the fireworks!
 
I forgot to mention the most difficult problem of all! I could not remove the cells from the bottom shell, because the bottom cell is stuck firmly to the shell. I tried taking off one end of the shell and using the spudger to pry the cell off, but it was stuck firm, and there was a risk of damaging the cell. In the end I carefully cut around the bottom plate of the shell, and that plate will probably have to remain stuck to the bottom cell . . I dare not try to unstick it. This is not a huge problem, unless you are trying to reduce weight to a minimum, and it does add strength to the assembly.
Use a heat gun being careful not to over heat the bottom as you pull on the battery board. That loosens the glue and the batterys come right out.
 
I have 855 flights and 198 hrs flying on my Mavic2 and found out about swollen batteries the hard way. Out of 10 batteries only 2 are good still. Buying 2 at a time. I put velcro tape around swollen batteries to hold them in. At a big risk, if I need more fly time, they do come back popped up. But can’t get Out. I was working on changing out the cells from batteries that are swollen. with the cells from the bricked or battery computer don’t work. To make more batteries. The dang batteries don’t last more than 6 months, right at the warranty date.
 
This is just a dumb thread. Just-nick is right. You already made the mistake of flying the aircraft into water... how will you feel when the battery blows up in your face... or worse... when it fails and crashes down from the sky? This hobby is not for some people... please refrain from dumb behavior and starting stupid threads. A wet battery is a damaged battery. Dispose of it properly please. Don’t risk an accident or the drone to save a $100. This is the dumbest sh@t I have ever read.
I would rather have the person ask a question dumb or not so they can hopefully get the answer that lead them in the right direction. Now, imagine if they did not ask and picked up a drill or a sawzall and dissected the battery and it gave A new name to Blazing Glory and hurt or even killed someone.. So, thanks for asking instead of reacting.
 

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