Two More Battery Failures

[Mordor]

Exactly.

 

[SkySight]

Good morning:

I, too, have had three of my original batteries swell. Here are the specifics for each:

#1 52 charges - manufactured 2018.8 - displays normal but swollen
#2 49 charges - manufactured 2018.6 - displays normal but most swollen. This battery is of greatest concern. Just picking it up unclipped it from the airframe
#3 49 charges - manufactured 2018.6 - displays normal but swollen
#4 44 charges - manufactured 2018.8 - displays normal but swollen
#5 1 charges - manufactured 2019.7 - bought as a replacement for #2 above due to excessive swelling

I'm a 107 pilot with almost four years experience. I do everything by the book having owned numerous UAS. I'm lead pilot for a SAR team here in Winston Salem, NC. My charger is a Sunnylife 6-in-1 charging station for the Mavic 2. I'm sure many of you are familiar with this device. Batteries are always cooled properly before re-use in that I have four and rarely fly them back to back. I'm careful to charge them in the order that they were purchased as displayed above. The slight puffing issue I've noted started a week ago and I thought it was limited to just one battery (#2) but now note the same swelling in the others as noted above. While I can insert the suspect ones in the airframe, I note that there isn't the resounding 'click' I always heard with them when new and do indeed hear with battery #5 after receiving it yesterday. When inserting the suspect batteries they do indeed seem to insert properly but the sound is 'soft' in comparison to the new one. Also, when replacing the used battery with a recharged one the slightest touch releases it, really giving me pause. The attached file displays the anomaly. The 'puffiness' isn't extreme but it is enough to perhaps become dislodged in the air and cause a crash.

Perhaps, if we can collectively ascertain if there is a similarity in the date of manufacture, we can get replacements from dji. As it stands now, all of my batteries are out of warranty. Your thoughts on this will be appreciated especially in lieu of the fact that there's a tariff increase due tomorrow and the idea of replacing three additional batteries doesn't sit well with me... One last parting thought; it was my understanding that we were supposed to get 200 cycles from these batteries. I'm getting 1/4 of the number promised.




The new battery is on the left (#5) and the most swollen one is on the right (#2). Both are cold.

 

[gnirtS]

My original thread in April with image is here:- Swelling batteries
Basically i can fit a coin inbetween the battery edge and the table. The balanced pen on top shows the curve too.
All batteries would unlock at the slightest touch of the airframe (or breaking in flight, or a wind gust etc etc).

I threw 2 away so cant get the manufacture date. I might one one in storage still. All were definitely before August 18 though as i ordered the drone the day it was released. So i guess made July 18 or earlier.

 

[Mordor]

Seems first batchs are problematic....jst for curiosity i will try put here photos of mine since i buy them no more then 1 month.

 

[Baba Narr]

Now a total of three batteries have failed (swollen). I use and care for my batteries properly so don't try and tell me I did anything wrong. I am convinced there was a bad batch or batches of batteries. Some these batteries have less than 30 charges. Since I rotate between five batteries they are all out of warranty.

No probople

Now a total of three batteries have failed (swollen). I use and care for my batteries properly so don't try and tell me I did anything wrong. I am convinced there was a bad batch or batches of batteries. Some these batteries have less than 30 charges. Since I rotate between five batteries they are all out of warranty.

I always store my batteries with only one green led showing. Even letting them run down to 70% is not enough to prevent possible swelling.
Always charge and use as soon as you can and there should be know problems.
Never store fully charged too close together and store in a cool place away from possible ignition sources.. just in case.
Happy flying.

 

[gnirtS]

I always store my batteries with only one green led showing. Even letting them run down to 70% is not enough to prevent possible swelling.
Always charge and use as soon as you can and there should be know problems.
Never store fully charged too close together and store in a cool place away from possible ignition sources.. just in case.
Happy flying.

People have done all that. And some batches are still swelling prematurely.

 

[GadgetGuy]

Depends what you class as failed electrically. If you count cutting off all electrical supply to the drone with no warning then yes, they can. They swell, they unlock, they cause connection between the battery and drone to fail.

Good point. Batteries that swell are always a problem. However, it is not as though they are suddenly swelling within a flight, and then dislodging without any advance notice. On the Mavic 2, the battery is also cradled in on top, and can potentially be secondarily tightly secured in place with a velcro strap, or that rain suit "thingy".

It sucks that it is happening at all. Fortunately, on my six M2 batteries, I haven't seen it, but 3 were bought in December, two in February, and one in June. Is DJI refusing to now replace any swollen batteries after the 6 month official warranty expires?

Appreciate the insight into the issue you are providing!

 

[gnirtS]

All of mine started out declining by being OK on the ground and swelling in flight. After that they graduated to really swollen cold and even worse when warm.

DJI certainly refused to have anything to do with my 3 batteries which were 7 months old (so 1 month over warranty)

 

[catowner7]

All three failures had the production date of July 2018.

Where do you find the production date? Here is the battery label of my M2Z a few days old.

 

[GadgetGuy]

Where do you find the production date? Here is the battery label of my M2Z aView attachment 80709 few days old.

It's under the Details page of the battery info in GO 4 when connected to the aircraft with the battery inside.

 

[dannybgoode]

I always store my batteries with only one green led showing.

I would humbly disagree with this. 1 led is too low and there is a danger of further discharge over time leading to the voltage collapsing below 3v.

From my RC heli days from memory the optimal storage voltage is somewhere around 3.8v per charge which is 65-70% of maximum. LiPo’s can be stored pretty much indefinitely (within reason if course) at this voltage and it is what most are shipped at and with good reason.

Is there any correlation between using non-stock chargers and swelling? I have a pretty early M2P and go between not using it for 2-3 months and then putting a number of flights on in quick succession so my batteries are subject to reasonably long periods of storage and then a number of full charge/discharge cycles then back into storage.

Generally (and I’m pretty bad for this) they’ll do the automatic discharge thing then sit there for weeks before I re-charge then and fly.

I only ever use the stock charger though and have done this both with my MA and M2P and have never had a hint of an issue on any of my packs.

 

[WithTheBirds]

I would humbly disagree with this. 1 led is too low and there is a danger of further discharge over time leading to the voltage collapsing below 3v.

From my RC heli days from memory the optimal storage voltage is somewhere around 3.8v per charge which is 65-70% of maximum. LiPo’s can be stored pretty much indefinitely (within reason if course) at this voltage and it is what most are shipped at and with good reason.

Is there any correlation between using non-stock chargers and swelling? I have a pretty early M2P and go between not using it for 2-3 months and then putting a number of flights on in quick succession so my batteries are subject to reasonably long periods of storage and then a number of full charge/discharge cycles then back into storage.

Generally (and I’m pretty bad for this) they’ll do the automatic discharge thing then sit there for weeks before I re-charge then and fly.

I only ever use the stock charger though and have done this both with my MA and M2P and have never had a hint of an issue on any of my packs.

3.8V is 40% state of charge. Self discharge is exceptionally low for LiION chemistry- the BMS electronics contribute more to discharge in storage however they will enter hibernation below 10%. If your keeping an eye on things one light is actually better than 2 (although not significantly) for storage.

 

[dannybgoode]

3.8V is 40% state of charge. Self discharge is exceptionally low for LiION chemistry- the BMS electronics contribute more to discharge in storage however they will enter hibernation below 10%. If your keeping an eye on things one light is actually better than 2 (although not significantly) for storage.

My apologies. My maths is bad atm! Brain still in holiday mode!

I would still be interested in any correlation between non-stock chargers and battery issues. I have consider getting one if only to be able to charge all packs together but am nervous as the DJI one just works.

 

[WithTheBirds]

My apologies. My maths is bad atm! Brain still in holiday mode!

I would still be interested in any correlation between non-stock chargers and battery issues. I have consider getting one if only to be able to charge all packs together but am nervous as the DJI one just works.

Given the charge circuitry is part of the battery (under/over voltage, current, temperature etc protection incorporated) what we call battery chargers in this application are nothing more than regulated DC power supplies. You will find plenty of user testimonials around the threads here for multi chargers. Better yet go over to phantomhelp.com where msinger gives some links to known good products.

 

[Mike4884]

My apologies. My maths is bad atm! Brain still in holiday mode!

I would still be interested in any correlation between non-stock chargers and battery issues. I have consider getting one if only to be able to charge all packs together but am nervous as the DJI one just works.

Yea i fly helis to and hear what u are saying and are right but these batteries are hv so i always just store mine at one light and 2nd light blinking which is like 35% voltage is around 3.80 per cell which is a good storage voltage....have not had any problems with swelling in any of my dji ac? and i use a aftermarket charger for my mavic 2 batteries also did for my og mavic pro no probs

 

[c.oberschneider]

2 of the 3 batteries that came with my m2p flymore - combo started to swell, one so massively that it nearly popped out of the drone after a 20 minute flight. I sent them in to DJI Europe exactly 1 year after the purchase (didn’t realise that until I looked at the original invoice) and just got the confirmation that both batteries will be replaced under warranty (we have 1 year warranty here in the EU). I hope that the 3rd battery that I have won’t go belly-up as well...
I can’t help out with the production date of the 2 swollen batteries (didn’t look it up in DJI GO4), all I know are the serial numbers, but I guess that won’t be of any help?
edit: bought my m2p combo on release day, if that helps.

View attachment 81023

 

[gnirtS]

If you use AirData or similar the battery data is stored in there.
Its going to be in the flight logs somewhere too.

 

[c.oberschneider]

If you use AirData or similar the battery data is stored in there.
Its going to be in the flight logs somewhere too.

Thanks, I’ll check that out when I find some time.

 

[gnirtS]

I bought mine in the UK (forgot about 1 year warranty) but was in Asia when they died.

I may email them anyway and see what they say BUT i think im a week out of that 1 year now.

 

[GadgetGuy]

2 of the 3 batteries that came with my m2p flymore - combo started to swell, one so massively that it nearly popped out of the drone after a 20 minute flight. I sent them in to DJI Europe exactly 1 year after the purchase (didn’t realise that until I looked at the original invoice) and just got the confirmation that both batteries will be replaced under warranty (we have 1 year warranty here in the EU). I hope that the 3rd battery that I have won’t go belly-up as well...
I can’t help out with the production date of the 2 swollen batteries (didn’t look it up in DJI GO4), all I know are the serial numbers, but I guess that won’t be of any help?
edit: bought my m2p combo on release day, if that helps.

View attachment 81023View attachment 81025

Exactly one year after the purchase date means the production date could not have been later than 2018.08 which is the latest suspect Production Date. You have helped! Third one will be the same as the other two, so at risk!