Some of my customers have contacted me regarding the batteries for the Mavic 2. In some cases, customers have experienced an issue with the batteries swelling up or “puffing”. This can be a serious issue and should not be ignored.
What causes a battery to swell and why is it important?
A swollen battery is a sign that the battery is failing. Lithium polymer batteries are constructed with thin layers coated with a chemical substance that contains lithium. Lithium is a volatile chemical if exposed to oxygen. Use caution, Lithium polymer batteries that are compromised can pose a fire hazard!
Batteries swell when the electrolyte in the battery decomposes. In the case of LiPo batteries, The nature of the electrolyte tends to produce gasses such as carbon dioxide (CO2) and carbon monoxide (CO) when they decompose. The layers of the battery are sealed in an airtight case. The production of these gases is what causes the LiPo battery to expand and swell.
Heat is the number one cause of a swollen battery, its a Lipo battery killer. Other things like running them all the way down, flying in wind or aggressive flying on a hot day can cause the internal temp to spike. 125 degrees seems to be the magic number not to exceed. It is possible to check the internal battery temperature in the app.
Another factor is the length of time they are sitting full. Public safety agencies understandably want their batteries to be fully charged and ready to deploy however, this will shorten the battery life.
What should I do if I discover a swollen battery?
If you discover this condition, the battery should be taken out of service immediately. Punctured batteries are a fire hazard and should be placed in a fireproof container for transport and properly disposed.
How common of a problem is this?
It seems to be isolated. Most of the agencies I work with have never experienced a problem with swollen batteries. I’ve been flying Mavics since they came out, sometimes hard and I’ve never experienced this but I understand its a problem.
What recourse do I have if my batteries are swollen?
I know a few of my customers that have contacted DJI support and have received replacements. DJI’s customer service is quite good and they have a reputation for standing behind their products.
Here is the link for DJI support:
What can I do to prevent my batteries from swelling?
For public safety agencies that need to be ready to deploy, I recommend you have twice as many batteries as you need to deploy. Keep half of them at storage charge (about 50%) and the other half fully charged. That way you have some ready to go and you can put the others on the charger if an incident comes up. Every week swap them.
Also, you don’t want to charge them when they are hot. If possible, let them cool down before recharging. I’ve used an igloo cooler on hot days. I have a cold pack on the bottom and a towel as an insulating layer to keep moisture off the batteries.
I did come across this video which offers a potential solution.
DJI recommends the following maintenance procedures for your batteries:
Batteries should be stored in a waterproof and moisture-proof place. If the battery is idle for more than 10 days, please discharge the battery to 40% to 60% of the total battery level. Recharge and discharge the battery once every 3 months to maintain battery activity.
I believe these strategies can prolong the life of batteries. Contact DJI support and see if you can get replacements and then enact these new procedures. I think you’ll have better luck. If you don’t receive a satisfactory response, please contact me and I will take steps to get it resolved.