Battery Bulge

[Rchawks]

As long as it fits comfortably into the drone is a slight deformation normal. Only one battery has this as the other two ar completely flat. The battery has 20 cycles on it, I hate to send it in if it's not going to be a problem for a long while. I should expect 300 cycles min, correct. Again the bump is slight and probably wouldn't show up in a pic.

 

[zocalo]

There are multiple cells within a given battery and, while it's hard to tell without seeing it, it sounds as if you probably have a single bad cell, or maybe two. When they fail, LiPO batteries tend to fail pretty spectacularly, so I'd recommend you contact DJI and see if they feel it's worth an exchange on the grounds of being better safe than sorry (assuming it's still eligable). Shipping suspect LiPOs also isn't something to be done lightly and they may prefer to just send you a replacement and let you dispose of that one, so it's definitely worth a shot.

Personally, I don't take any chances with my LiPOs, but YMMV if it's a as minor as you imply. Even so, I'd definitely be using that battery as a last resort, being very careful about where I keep it, and closely monitoring the situation - if the bulge continues to grow, then I'd seriously recommend replacement and safe disposal, even if it means buying a new battery yourself. Keep in mind that batteries tend to fail because of shorts - which can be caused by the cell expansion you are describing, or by thermal expansion when under load, e.g. when it's in the air. Is it *really* worth the risk?

 

[PhantomFandom]

As long as it fits comfortably into the drone is a slight deformation normal. Only one battery has this as the other two ar completely flat. The battery has 20 cycles on it, I hate to send it in if it's not going to be a problem for a long while. I should expect 300 cycles min, correct. Again the bump is slight and probably wouldn't show up in a pic.

My view is that there is no such thing as an acceptable amount of swelling. If it is the least bit deformed, I would immediately decommission that battery. It's not worth the risk, either of failure during flight or exploding during charging.

 

[Capt Lard]

I agree with Phantom, caution is required with lipos.

 

[Jet skier]

You need to send them in to Dji there’s no room for expansion in the battery compartment and you don’t want to force pressure on the latches I just sent two batteries in myself waiting to hear from them

 

[lee82gx]

All lipos have a small amount of bulge. All 3 of mine show some. I'm of the same thought as you, if they sit well on the drone and performance wise appear normal, I'd use it.

 

[hiflyer201]

I just sent two batteries in myself waiting to hear from them

I hope you post their response.

 

[PhantomFandom]

All lipos have a small amount of bulge.

Sorry but that is not at all true. Between all my drones, I have dozens of batteries and I don't use a single one with any sort of bulge. I have in the past year had two batteries with a bit of swelling and they were immediately retired.

I'm of the same thought as you, if they sit well on the drone and performance wise appear normal, I'd use it.

They "appear" normal until....they don't. It is your call and decision on what level of risk you desire to take with your UAS.

 

[Deleted member 114292]

I have 11 batteries between my P4 and M2P and none of them show any swelling. And some are 4 years old.
The thing is all lipos swell to some degree, but in a hard plastic case you should not see it.
If you do it's bad.

 

[Thomas B]

I have 10 batteries for my M2P. Had slight swelling in one... will still latch... but I retired it to no flying uses only as I have had a failure in flight and was lucky to land. I don’t fly faulty equipment in my drone... batteries are cheaper.

 

[hiflyer201]

I have/had 11 batteries. The only batteries that swelled were two of the three Mavic Air 1 batteries. The Mavic Air1 battery that stayed flat...Flat.a.. failed in flight.
I'm still using one slightly swollen Mavic Air 1 battery. I only use it for up close and low active flight and figure eights in the back yard and I wait until it's dead cold to charge it. I keep a close look at it on AirData and it hasn't lost but a slight amount of performance. On airdata it show's one red cell but I keep it on battery while flying and the cells are always three in the green?
Re-reading this..I realize that I would never advise someone else to do what I'm doing

 

[lee82gx]

Sorry but that is not at all true. Between all my drones, I have dozens of batteries and I don't use a single one with any sort of bulge. I have in the past year had two batteries with a bit of swelling and they were immediately retired.


They "appear" normal until....they don't. It is your call and decision on what level of risk you desire to take with your UAS.

In my industry, we usually include a tolerance for cell pack expansion as it will occur. The mavic air 2 battery housing also has some air gap for cell expansion. It'll defy a lot of physics if you expect a cell pack not to expand at all. What I do mean is to accept the type of expansion that does not bulge out of the whole battery housing envelope.

 

[PhantomFandom]

What I do mean is to accept the type of expansion that does not bulge out of the whole battery housing envelope.

OK and that is completely different. If there is expansion beyond the visible battery housing envelope (of any kind), then that battery has an issue and should not be used. That is what I thought we were discussing here; not slight internal cell expansion.

 

[zocalo]

OK and that is completely different. If there is expansion beyond the visible battery housing envelope (of any kind), then that battery has an issue and should not be used. That is what I thought we were discussing here; not slight internal cell expansion.

OP describes it as a slight deformation that doesn't prevent insertion into the drone and is unlikely to show up in a picture; the two other batteries they have are described as "completely flat", so there's clearly a physical discrepency between the three. That strongly implies a very slight physical bulge on the outer plastic shell of the battery to me, and not normal cell expansion that would be contained by the internal structure and battery case.

There's a lot of YMMV on such marginal cases, personally I'd be straight in touch with DJI to try and get them to replace it (it's always worth a shot), but if they refused then I'd almost certainly be retiring the battery anyway. My posisiton is that if it's if bad enough to notice, then it's bad enough to fail in flight or on charge, and it's not worth losing a drone (or worse!) for the sake of a new battery. If it really is marginal though, then I'm well aware that some will continue to fly it and monitor the situation too see if it's stable in the new state (which is possible), but if the OP - or anyone else - is considering doing that with a battery in that state then I'd *strongly* recommend that you also think really hard about where you are operating and what might happen if the battery should fail. As a pilot, you're generally responsible for all aspects of your flight, and that would include such things as a burning drone crashing into crowd, a building, or a tinderbox landscape - is that *really* worth the risk?

 

[kidroc]

As long as it fits comfortably into the drone is a slight deformation normal. Only one battery has this as the other two ar completely flat. The battery has 20 cycles on it, I hate to send it in if it's not going to be a problem for a long while. I should expect 300 cycles min, correct. Again the bump is slight and probably wouldn't show up in a pic.

No it's not safe ditch that battery before it's to late..

 

[heyengel]

You need to send them in to Dji there’s no room for expansion in the battery compartment and you don’t want to force pressure on the latches I just sent two batteries in myself waiting to hear from them

How old are your batteries? Any updates from DJI? I have 3 of the original batteries when the Mavic 2 came out and they're all swelling.

 

[ChrisOutdoors]

I've got 4 MPP batteries used since 2017 with over 150 charges each. They all have swelling and I'll continue to use them until they can't latch well. I've never heard/read of any DJI batteries that exploded under normal use and using DJI charging hubs.

Curious to learn more on some different thinking, why do some of you stop using slightly swelling batteries? Where have you gotten your information that any type of swelling is bad and use should be terminated?

 

[lee82gx]

I've got 4 MPP batteries used since 2017 with over 150 charges each. They all have swelling and I'll continue to use them until they can't latch well. I've never heard/read of any DJI batteries that exploded under normal use and using DJI charging hubs.

Curious to learn more on some different thinking, why do some of you stop using slightly swelling batteries? Where have you gotten your information that any type of swelling is bad and use should be terminated?

Battery swelling is a sign that the "dendrites" have formed inside the cells, and it is usually poorer in performance at minimum. At worst, it can mean no more space to any further "swell" and it will self puncture, which is catastrophic. For Mavics, when they swell a lot, it counteracts with the latch which can cause an ejection of battery or unlatch in midflight. Even if it stays there, the battery contact will have reduced engagement or "poor connection".

 

[Mike4884]

If this was an RC helic I wouldn't have no problem using it as I have in the past or an RC car but it's definitely unsafe for the mavic reason being the battery compartment literally has no room for swelling.... So before flight you have a tiny bit of swelling and think it's okay you put the battery in and go on with your flight well batteries tend to get hot during flight, and swell a little bit......and with the way the mavic air 2's battery compartment is it's either going to come back to you slightly raised (the battery) a couple millimeters or you're just going to lose power all together one of these times.... I wouldnt risk it dude