Battery Swelling - beware - near accident today

[DanMan32]

One more tip to prevent swelling: never store them charged! Most people charge them directly after a flight session.
Normally I end with about 20% rest charge. I leave them like that until I know I will fly again, then charge them in the morning with a timer. If not flying for a long time, check batteries every 2 months or so and charge them until the second LED starts flashing.
BTW, DJI just changed the default time for automatic discharge for M2 P/Z to 2 days!

I know they changed the default days to 5 where it originally was 10. That was after the rash of swollen batteries last summer. Do you have documentation that the default is now 2?

 

[WDKZoom]

The primary cause of swelling has to do with # charges you put them through, the temperature playing a low factor in the life of the battery. The research I've done on li-po batteries suggests your battery habbits play a large part in how long they'll last. Do you fly until the batteries are in the single digits, if so that really shortens their life. Do you use a longer discharge time of 10 days or more, that wears them down, or worse, always keep them fully charged. The ideal storing of batteries is in a cool, dry location at 50%. Are you using an aftermarket charger that "miraculously" charges the batteries 10-20 min faster then DJIs? If so, the trade off is heat and battery longevity.

Regardless, at some point li-po batteries will swell.

I've had my MPP since 2017 with 4 new batteries. 1 started swelling around the 180th charge and the 2nd around the 190th charge. I expect the 3rd and 4th will start soon, pushing over 200 charges on all 4 batteries. I'll keep using the swollen ones this winter and likely replace by spring.

Looking at aftermarket batteries now due to the ridiculous
price for new DJI batteries.

I'll be excited for the day we can move away from li-po, swelling in batteries that cost over $100 after a few hundred charges seems ridiculous.

I completely agree with everything you said. I am still wondering if a battery showing no signs of swelling, some where around 50 charges, treated in the exact way you describe as I do mine will swell enough in “one flight” to pop out of position under DJI’s cold and heat restrictions?? One with prior problems and swelling perhaps. I won’t use a strap, though if using one gives someone some peace, all well and good all be it keeping in mind that a swelling battery is more likely to burst into flames also bringing your pride and joy screaming to the earth. I will still take my chances with thorough inspections before and after every flight.

WDK

 

[WDKZoom]

That's just not true. Three of my batteries experienced swelling and I have less than 50 cycles on them. However I did tend to leave them in the car too long, fully charged. The swelling showed up late summer after almost a year of ownership. The majority of swelling occurred during summer.

Laptops are now offering settings to charge only to 80%. They recommend this setting if the laptop is plugged in most of the time where the battery would otherwise be at 100% most of the time.

Even though a problem may not have immediately shown itself, leaving a lipo battery in a very warm to hot car fully charged may have caused irreparable damage. Any battery subjected to over heating what ever it’s parameters are, it’s life is going to be shortened.

WDK

 

[ChrisOutdoors]

That's just not true. Three of my batteries experienced swelling and I have less than 50 cycles on them. However I did tend to leave them in the car too long, fully charged. The swelling showed up late summer after almost a year of ownership. The majority of swelling occurred during summer.

Laptops are now offering settings to charge only to 80%. They recommend this setting if the laptop is plugged in most of the time where the battery would otherwise be at 100% most of the time.

You put your batteries in the worst condition, no wonder they only lasted 50 cycles. Temperature is a minor issue under NORMAL outdoor conditions. Car in the summer is essentially a greenhouse, only an oven would have been worse.

 

[QLD-pilot]

I notice that flying in hot sunny weather makes my battery quite hot, just from the sun exposure.

Idea: what about spray painting the battery top white? White surfaces are much slower to heat up in the sun

 

[Thomas B]

I notice that flying in hot sunny weather makes my battery quite hot, just from the sun exposure.

Idea: what about spray painting the battery top white? White surfaces are much slower to heat up in the sun

Heat increase on hot day is due to the ambient temp of cooling air.

 

[QLD-pilot]

Heat increase on hot day is due to the ambient temp of cooling air.

Place your battery in the midday sun on a hot day. Come back 30 minutes later and see how hot it is. The sun can impart considerable heat

 

[Thomas B]

Place your battery in the midday sun on a hot day. Come back 30 minutes later and see how hot it is. The sun can impart considerable heat

Gave owners credit for knowing this is bad practice.

 

[jimlips]

I'm guilty of always keeping my battery charged - you never know when you will need to run out and video something! Don't have time to wait for four batteries to charge. The event will be gone by then.

I wish they made a Mavic-Pro sized battery holder for Energizer Ultimate Lithium batteries. Then I could let my regular Lipo batts store at 50% where they belong, and still have a "ready-to-go" battery pack that has a great shelf life (supposedly 15 years).

Someone with a 3D printer may be able to design this. The only thing I'm not sure they would be able to handle is the amount of pulse current necessary for a drone. It would be a fun experiment, though.

 

[QLD-pilot]

Gave owners credit for knowing this is bad practice.

Geez, I'm not saying "you should not leave your battery in the sun", which we all know (or should know), I'm saying that if your battery is in the sun for 30 minutes, AS IT IS DURING A FLIGHT ON A HOT, SUNNY DAY, then the sun alone will heat it up, quite apart from the heating caused by using the battery. Not sure why nobody gets this?

Edit: someone who owns multiple batteries can do this experiment: spray paint one battery white, and then put it and another normal battery in the sun for 30 minutes. Then use an infrared thermometer to test both temperatures. Thanks!

 

[WDKZoom]

Geez, I'm not saying "you should not leave your battery in the sun", which we all know (or should know), I'm saying that if your battery is in the sun for 30 minutes, AS IT IS DURING A FLIGHT ON A HOT, SUNNY DAY, then the sun alone will heat it up, quite apart from the heating caused by using the battery. Not sure why nobody gets this?

Edit: someone who owns multiple batteries can do this experiment: spray paint one battery white, and then put it and another normal battery in the sun for 30 minutes. Then use an infrared thermometer to test both temperatures. Thanks!

of course your battery is going to heat up but if your flying within the heat parameters set by DJI, you can bet this has been tested and should not be a problem.

WDK

 

[QLD-pilot]

of course your battery is going to heat up but if your flying within the heat parameters set by DJI, you can bet this has been tested and should not be a problem.

WDK

It would still be great to know how much passive solar thermal protection we can add to the battery, given that they are expensive and seem to fail prematurely for some people.

 

[WDKZoom]

It would still be great to know how much passive solar thermal protection we can add to the battery, given that they are expensive and seem to fail prematurely for some people.

That would be a good thing perhaps but even then people will disregard the limit and blame it on the battery. DJI for the mavic recommends that you do not fly below 32 degrees and above 104 degrees I don’t fly above 95 degrees not because of the battery but because the motors get hot so I stay well below the max.

WDK

 

[Thomas B]

It would still be great to know how much passive solar thermal protection we can add to the battery, given that they are expensive and seem to fail prematurely for some people.

Not useful given that DJI states that ambient temp of 104 degrees F is max recommended. I too recommend keeping batteries out of the sun though.

 

[QLD-pilot]

Not useful given that DJI states that ambient temp of 104 degrees F is max recommended.

One assumes people with premature swelling are not flying over 40°C (104°F). But despite following the rules, the batteries are still swelling, for some people. That's why I'm interested in what further things can be done to keep batteries cooler in hot weather.

 

[jsflyrv]

I live in Georgia...the new Arizona. Over the last 4 years I’ve lost 4 P4P batteries and 3 M2P batteries due to swelling. Gets pricey replacing them too. Now I know not to even think about flying with a swollen battery. When this 1st happened, I noticed when landing I had to forcefully remove the battery from the P4P. One of the batteries on the Mavic 2 Pro buldged until it cooled down. I thought I would try it at low level testing and when I exhausted the charge during flight it buldged again so I decommissioned it. As I said they are pricey but a lot less expensive than a drone.

The old brick 3,4 and 6 cell batteries were notorious for swelling once they heated up. They were pretty much worthless once they swelled up. To try to recharge them was a fire waiting to happen.

 

[Thomas B]

One assumes people with premature swelling are not flying over 40°C (104°F). But despite following the rules, the batteries are still swelling, for some people. That's why I'm interested in what further things can be done to keep batteries cooler in hot weather.

Never assume was drummed into me as a child.

 

[QLD-pilot]

Never assume was drummed into me as a child.

So you suspect they are flying over 40°C? Interesting. Those temps are fairly rare

 

[WDKZoom]

One assumes people with premature swelling are not flying over 40°C (104°F). But despite following the rules, the batteries are still swelling, for some people. That's why I'm interested in what further things can be done to keep batteries cooler in hot weather.

You do have a point, however we only know of the battery complaints made here which “May” be a tiny tiny fraction of all the Mavic series out there.

WDK

 

[Jerdog]

The issue is heat , period. The batteries are sealed so tightly in the plastic case that during charging and discharging they get very warm. The heat causes the battery wafers to expand. Mine went down when the battery clips failed after the battery expanded during a cool weather flight at 70 deg F. This is an inherent problem with the design and or manufacture of the battery and will happen without notice. DJI will not stand behind their product as designed. So unless you purchase their refresh policy you are screwed. Mine crashed destroying 1 motor arm and the Hasselblad camera. Cost of parts $700 to repair. Velco straps may help but once a battery has expanded too far the lock clips will not engage. This is a bit infuriating as DJI doesn't really care.