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Strange battery burn while charging?

On the off chance there's some sort of issue with the charging hub, you could charge for 5 or 10 minutes then remove batteries and scan contacts with an IR thermometer or IR camera (if you have one handy). That would show up any anomalies.
 
The connector maintains it's basic shape and the battery is working. Only the edge of the connector is melted. It looks like the damage is caused by something hot like a cigarette running over the outside of the connector.
 
Perhaps the issue is with the faulty batteries BMS board and nothing external?
 
The connector maintains it's basic shape and the battery is working. Only the edge of the connector is melted. It looks like the damage is caused by something hot like a cigarette running over the outside of the connector.
Don’t smoke,looks almost like a file was took to it other than the white. Might could take one and smooth off the top and get the door to close.
 
Perhaps the issue is with the faulty batteries BMS board and nothing external?
No idea but where the terminal is on the battery looks fine its just the top of the battery.
 
Dirk...... that white stuff is most likely something from INSIDE the battery, no?

I know you said you couldn't find cracks or anything, but still I'd be very careful, at least until you know what it is, where it came from, and why.

Remember, I'm far from an expert on this!
 
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Dirk...... that white stuff is most likely something from INSIDE the battery, no?

I know you said you couldn't find cracks or anything, but still I'd be very careful, at least until you know what it is, where it came from, and why.

Remember, I'm far from an expert on this!
Thanks and yeah. No clue and not going to mess with it other than drain it.
 
you could just take the thin line of tape that runs around the join between the main case and the top, to see if the cells have any damage or burn marks after you have discharged it some
be careful that if there is any leakage to keep it off your skin wear some protective gloves when you do it
 
This is a clear indication of a high resistance connection and a resulting intermittent arc while voltage was applied to those terminals (identified as hi dc by OMM). This happens a lot in similar battery systems including those for other portable electronics (laptops, games systems, tablets, battery or juice packs,etc.) and typically happens where the conductor forms a bend as that is a stress point that may fracture or partially separate (which creates the area of high resistance, which also generates heat - think of your radiant electric range coils). Even DC at these voltages can generate sufficient temps to ignite both the plastic case and nearby ordinary combustibles. While you have the charger take another look for any artifact or damage around the contact pins (beading, deformity, areas where it looks eaten away at all). This can be done with a macro close up photo and magnifier. It is hard to tell from your photos but the fault looks to be in the case of the battery as opposed to a fault on the pins that are exposed.

The only way to definitively look at the specific point of failure is to xray the damaged component and also a working one (exemplar) to look for the fault. If this caused damage to your home, your insurance carrier would likely pay an electrical engineer to conduct a lab exam to identify the failure point and pursue cost recovery from the manufacturer. Thankfully this does not seem to be the case here.

Fortunately you were not injured and your home was not damaged, but this is a really clear example of the need to think about where you charge and store your gear, and make sure that while charging you are in attendance and aware of what is happening. While some aftermarket case manufacturers advertise the feature of "charge in case" (I own one - great case) not so sure that is a prudent move as if this were to occur and the charger is surrounded by the foam insert, the heat has no place to go and it would likely have ignited and been much more exciting.

This is almost serious enough that you might wish to consider notifying the CPSC (consumer protection safety commision) who is responsible for initiating recalls of defective components that present a risk of injury or loss of life. If this happened and it ignited your home, the result could have been tragic. DJI should respond aggressively and want the component back and will likely also want the charger (both components need to be looked at to see the problem in their totality). You can file a report with them online (cpsc.gov) all this does is add your experience to the database so that if there are cluster appropriate action can be taken to help keep others safe.

For the rest of the community that has a mini, let's be especially vigilant and careful until a definitive finding as to WHY this happened is arrived at.

Some suggestions:

  1. ONLY charge on non-combustible surfaces in an open area (not on the bed, not on carpet, not in the case, not in the car unless your present)

  2. MONITOR your charging: do not plug and leave it overnight or in the garage/closet/basement where you cant see, hear, smell the unit charging.

  3. INSPECT connectors for damage, oxidation, moisture, corrosion, etc.

I see MANY fires in residences and vehicles where the root cause is a defective battery component and/or charger such as this (even on very high quality high end devices), so it is not as uncommon as you think.

Be safe and thank you for sharing your experience. We can all learn and profit from it.
 
Spooky stuff! Thought there was enough to worry about on the mini without worrying about batteries. What is your plan for draining it? I use spare battery packs if you can put it back in the charger or mini. Good luck.
 
Looks like leaked battery matrix/acid.
Just took it to a friend that has one of those souped up scopes and is really a electronic geek we could not see any cracks or anywhere anything could have leaked out. What he thinks happened was it was just a bad battery. He thinks the top of the little connecters that are under that top had arced and what i was seeing on the top was where it had got hot and caused that. Thats all we could come with and after looking at it it made sense to me.I took my knife and tried to scratch that white off but just exposed more discoloration there like it had got hot.
So if thats not it i don't know and just going to drain it in my mini and send it back to the vender and sure he will send another and they can figure it out .
Is strange though and was the reason i made this thread to show you.
Thanks guys to all that responded or took time to look and as always
you guys stay safe. Thumbswayup
 
be careful that if there is any leakage to keep it off your skin wear some protective gloves when you do it
Don't worry my other hobby is recovering gold from old PC scrap so i mess with acids a lot. Thumbswayup
Spooky stuff! Thought there was enough to worry about on the mini without worrying about batteries. What is your plan for draining it? I use spare battery packs if you can put it back in the charger or mini. Good luck.
Agree and being it still will connect just not let the door close i will let it hover low till it drains it down as far as it will go.Thumbswayup
 
Interesting thread anyhow. A first as far as I know. Actually glad it happened to a regular as I’d been tempted to tell a newbie what he did wrong. LOL

Best wishes, stay safe

all those drones and no P4’s.? skipped right to MP’s. Understand the introduction timing. Big bad (good) to small powerful. ?
 
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Just took it to a friend that has one of those souped up scopes and is really a electronic geek we could not see any cracks or anywhere anything could have leaked out. What he thinks happened was it was just a bad battery. He thinks the top of the little connecters that are under that top had arced and what i was seeing on the top was where it had got hot and caused that. Thats all we could come with and after looking at it it made sense to me.I took my knife and tried to scratch that white off but just exposed more discoloration there like it had got hot.
So if thats not it i don't know and just going to drain it in my mini and send it back to the vender and sure he will send another and they can figure it out .
Is strange though and was the reason i made this thread to show you.
Thanks guys to all that responded or took time to look and as always
you guys stay safe. Thumbswayup
I think if it had arced where the battery is connected/soldered to the BMS board, the damage would appear almost exactly in the center of the circular part of the cap, 15 mm from the damaged area on your cap . That is the location of that connection. The 18650 cells used in this battery have a vent for safety. In the event the pressure inside the cell approaches a dangerous level because of heat, the vent opens to avoid a possible explosion and or fire. And I assume that the cell would then be tits up. The engineers should have used a fire proof material for the cap. I think the GOOD QUALITY 18650 cells are very safe more than they are very dangerous. But we need to be careful. Maybe you had a little fire?
Looking forward to the final verdict.
 
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Well i really don't know what happened. I just flew it down to 0 and will return it to vender. If i had a fire i don't know where it was as it wasn't in the bag or in my charging hobby room. I really have no clue.
 
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Thanks for the picture. is it yours and if so did the top just pop off or what .
Never mind just looked and see about what you have to do
to get to that spot and do mean to return it and not gonna.
But just relooked at the top and is hard to see it but is a circle in the center of the top that is discolored like it was hot.
98326484-9835-4865-AA42-802FCAF2529C.jpeg
 
Well i really don't know what happened. I just flew it down to 0 and will return it to vender. If i had a fire i don't know where it was as it wasn't in the bag or in my charging hobby room. I really have no clue.
What I meant by fire. I thought one battery may have vented and the gases made a small fire, when the gasses contacted the air, like a Bic Lighter. Just for a short period of time and went out, which caused the visable damage.
If it was being charged in a Lipo bag, some evidence of the fire would have appeared there.
So I withdraw my hypothesis.
Thank you for sharing this.
 
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@dirkclod
hi Dc looking at the picture of the opened battery case it appears that there was an issue somewhere in the battery control board during charging
according to the manual the battery has overcharge, over temp,and cell balance protection which is supposed to stop the charging process if it detects a fault
maybe in your case the board had a fault which prevented those things from happening,
 
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