Weird battery problem - PH4-5870mAh battery

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Hi everyone.

I have a phantom 4 advanced and am using the high capacity batteries (PH4-5870mAh).

Around 5 minutes into a flight I got the 'Battery Damaged' message on the controller and decided it might be a good idea to get the bird home and land immediately. I did this without problems.

Checking on Airdata later I found something weird, screenshot attached below. I know battery cells can fail but never seen one cell go high and another low - a perfect mirror image of each other. Any ideas what might cause this?

I did try fully recharging the battery and then doing a nearby low test flight and the same thing happened a few minutes into the flight. Interestingly over the course of the log the problem appears and disappears, as you can see from the screenshot of the original problem flight.

The battery has done around 10 flights only and, at least I think, I've looked after it - i.e. I store it half charged, charge it fully before a flight, let it cool before recharging, etc. Unfortunately its just over 1 year old so I don't think DJI would do anything - maybe its just bad luck and I will have to relegate it to the bench for powering updates and stuff.
Battery_Problem.png
 
Try discharging it to zero and recharge using DJI charger. I read somewhere here that doing so initializes battery. It is what I do when I see significant voltage variance between cells on my P4P batteries. I did it once on my 1 year old batteries.
 
Also make sure your battery firmware is up to date. Have you noticed any swelling or deformity to the battery either before or after the flight. If you plug it in does the charger go straight into flashing green. Just looking for any additional indicators that this battery has gone bad. It does happen so good call to bring it home early. If you need to replace a battery we have p4 batteries in stock. Just visit our website for details.
 
Also make sure your battery firmware is up to date. Have you noticed any swelling or deformity to the battery either before or after the flight. If you plug it in does the charger go straight into flashing green. Just looking for any additional indicators that this battery has gone bad. It does happen so good call to bring it home early. If you need to replace a battery we have p4 batteries in stock. Just visit our website for details.

Thanks for the reply.

The battery firmware is up to date. I haven't noticed any swelling or anything unusual either before or after flying. If I plug it into the charger it appears normal - i.e. it starts to charge as usual - the same flashing LED pattern as charging a good battery.
 
Hi everyone.

I have a phantom 4 advanced and am using the high capacity batteries (PH4-5870mAh).

Around 5 minutes into a flight I got the 'Battery Damaged' message on the controller and decided it might be a good idea to get the bird home and land immediately. I did this without problems.

Checking on Airdata later I found something weird, screenshot attached below. I know battery cells can fail but never seen one cell go high and another low - a perfect mirror image of each other. Any ideas what might cause this?

I did try fully recharging the battery and then doing a nearby low test flight and the same thing happened a few minutes into the flight. Interestingly over the course of the log the problem appears and disappears, as you can see from the screenshot of the original problem flight.

The battery has done around 10 flights only and, at least I think, I've looked after it - i.e. I store it half charged, charge it fully before a flight, let it cool before recharging, etc. Unfortunately its just over 1 year old so I don't think DJI would do anything - maybe its just bad luck and I will have to relegate it to the bench for powering updates and stuff.View attachment 108912
Any unsurity on batt dangerous,,had a p4 drop from useing bad battery,,don't fly it,,I know they not cheap either but cheaper than a new drone
 
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Any unsurity on batt dangerous,,had a p4 drop from useing bad battery,,don't fly it,,I know they not cheap either but cheaper than a new drone

Very true! It certainly isn't worth losing or crashing the drone for the sake of buying a replacement battery. I was just curious if anyone has seen this same fault before - it doesn't appear to be a faulty cell, more a fault on the monitoring side. I might open it up and have a look around, but I don't think I'd ever risk flying with it again.
 
Very true! It certainly isn't worth losing or crashing the drone for the sake of buying a replacement battery. I was just curious if anyone has seen this same fault before - it doesn't appear to be a faulty cell, more a fault on the monitoring side. I might open it up and have a look around, but I don't think I'd ever risk flying with it again.

Be careful, as always, opening any batteries carries considerable risks. Safety first! Also, it may void your warranty... [emoji2]
 
Just a follow up if anyone is interested in this problem:

I did pull the battery apart after discharging it down until the drone shut off (but thanks for the warnings, this isn’t a risk-free operation and it helps to know your way around surface mounted electronic PCBs – I wouldn’t recommend this to someone without prior experience) but couldn’t find anything obviously wrong.

I was pretty convinced this is merely a monitoring problem, rather than any actual problem with the cells themselves, mainly because the total voltage output stays exactly the same when the problem occurs, i.e. cell one goes a certain voltage low and cell 2 goes exactly the same voltage high. I can’t think of anything reasonable going on within the cells that could cause this effect – it has to be a problem either with individual cell connections to the PCB or something on the PCB.

With this in mind I made sure the small ribbon cable that connects the individual cell terminals to the board was fully cleaned and re-seated at each end. I also applied fresh solder around this area of the board, specifically on the four 100R resistors, one on each cell line and the four other 3 terminal devices (I assume transistors or similar) connected to each line.

With the battery back together I fully recharged it and tried it out in the drone. All four cell voltages showed a full charge and there were no warnings. I then hovered the drone at very low altitude, so it would hopefully survive if the battery suddenly died, until I reached the low battery warning point. Importing this flight into Airdata showed no battery problems whatsoever, no deviations anywhere even close to being a concern.

I’m not sure I would risk a normal flight using this battery though, as someone said above it just isn’t worth it really and I will probably just use this battery on the bench for updates etc.

I’ve not seen anything like this fault before on this forum, so hopefully it will be of interest.

Happy flying!
 
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