Air 2S Batteries - BMS Issue? Drone powers up on inserting battery that is turned off??

[rustyc]

Had strange issue with Air2S batteries, Both died within a few days of each other, battery health shows cells are equal which I presume are OK, see screenshots.
Batteries will power drone up upon inserting them, even though batteries are turned off. Turning battery on and off makes no difference, drone stays powered up. Batteries have no sign of swelling. Batteries won't take a charge so figuring the BMS has faulted / died. Took them into DJI Store and they checked them and couldn't explain what was going on with them. They suggested that I contact DJI Service which I did, but as they are out of warranty they not being too helpful. I would have expected the batteries last longer than 50 recharges or so.
Anyone else had this issue? If so did you get them fixed?
Thanks

 

[Cafguy]

I would have expected the batteries last longer than 50 recharges or so.

I have about 12 of these on chargers now. If you store and treat these batteries properly you should get a bit over 220 cycles or so Your batteries could have died for a number of reasons. Conditions of where you store them, Keeping them stored at too high or too low a charge etc...here are a few tips on getting Advice on your problem.
You may hear a suggestion telling you to download BatteryKilleR and get yourself a soldering iron. If you are new to Electronics and know little about Batteries, DON'T EVEN TRY THIS! If you know what you are doing, or you know someone that is, you can Fix those Batteries BUT for the Cost of air2 batts its just not worth it.
1. Purchase new or "low Cycles used" used batts on ebay -you can get them cheap.
2. Get a decent charger not a DJI charger. you want a charger that will charge all the Batteries at the same time, AND most importantly you want a charger with a Storage charge option.
3. Keep your Batteries at 60% as much as possible NEVER charge to 100% and put them away! No matter who tells you different!
4. keep them away from heat and direct sunlight!
5. Finally for safety Do not charge any Battery unattended!
I fly the Air 2S for my security business and I have gone thru a hundred of these batteries I average around 225 or so cycles and flight times start to degrade at about 200.

 

[sawman]

@Cafguy What charger do you recommend? Thanks

 

[Cafguy]

I use Hanatora chargers with storage option

Amazon.com

 

[HeliDog]

I noticed my batteries do an automated self discharge if not used for a period. That is not suitable for storage in a pinch?

 

[Cafguy]

It depends on whom you ask Honestly but I don't think so, best to have the ability to keep them at 60%

 

[Max Headroom]

Moved.

 

[Kilrymont]

It depends on whom you ask Honestly but I don't think so, best to have the ability to keep them at 60%

I have no particular expertise in battery tech myself but I pay attention to what manufacturers tell me. I bought a Lenovo laptop that had a battery maintenance routine inbuilt to the machine that kept that kept the battery charge level around the 60% level. Unless the owner overrode it. That battery was still in use when the computer wore out, with hinges dislocating themselves plus other things entirely unrelated to the battery.
The maker’s advice was that charging to 100% was all right if your use demanded such but that this should be minimised.
My Phantom4 batteries can be set by the owner to start self discharge to about 65% after the no. of days convenient to the user. Other drones seem to vary re whether the owner can set the days before self-discharge to 65% begins.
All the above ignores that these batteries do lose charge capacity over time. There’s a “hibernate” state Ive seen referred to, but at no point is the charge level quantified at this hibernate state.
I have elderly DJI batteries for the above units and more.
They have all been charged on DJI OEM chargers exclusively. They’re at most around 6-7 years of age, and reach the voltage they should when charged, and discharge evenly over the cells each contains. Their capacity seems to be about right, if flight time is the measure used,
Given that the giant computer Co. Lenovo and DJI seem to agree re this 65% charge maintenance level, given the behaviour of my own kit, I see no reason to distrust DJI’s take on battery lifespan preservation.

I have an electric bike that I seldom charge fully, using the several LEDS on the Bosch battery to estimate charge level to the region of 60% - precision isn’t possible. An occasional full charge shows a miles-capacity forecast virtually unchanged from new when COVID first hit. I’m old and don’t really need to have long range capacity in this bike so this pattern of use and charge suits me well enough. (A young rider pushing lots of miles in a day would have sterner demands than me)

 

[HeliDog]

I have no particular expertise in battery tech myself but I pay attention to what manufacturers tell me. I bought a Lenovo laptop that had a battery maintenance routine inbuilt to the machine that kept that kept the battery charge level around the 60% level. Unless the owner overrode it. That battery was still in use when the computer wore out, with hinges dislocating themselves plus other things entirely unrelated to the battery.
The maker’s advice was that charging to 100% was all right if your use demanded such but that this should be minimised.
My Phantom4 batteries can be set by the owner to start self discharge to about 65% after the no. of days convenient to the user. Other drones seem to vary re whether the owner can set the days before self-discharge to 65% begins.
All the above ignores that these batteries do lose charge capacity over time. There’s a “hibernate” state Ive seen referred to, but at no point is the charge level quantified at this hibernate state.
I have elderly DJI batteries for the above units and more.
They have all been charged on DJI OEM chargers exclusively. They’re at most around 6-7 years of age, and reach the voltage they should when charged, and discharge evenly over the cells each contains. Their capacity seems to be about right, if flight time is the measure used,
Given that the giant computer Co. Lenovo and DJI seem to agree re this 65% charge maintenance level, given the behaviour of my own kit, I see no reason to distrust DJI’s take on battery lifespan preservation.

I have an electric bike that I seldom charge fully, using the several LEDS on the Bosch battery to estimate charge level to the region of 60% - precision isn’t possible. An occasional full charge shows a miles-capacity forecast virtually unchanged from new when COVID first hit. I’m old and don’t really need to have long range capacity in this bike so this pattern of use and charge suits me well enough. (A young rider pushing lots of miles in a day would have sterner demands than me)

As long as the DJI charger properly balances the cells, I'll continue to use them. Easy enough to check. Got lots of lithium RC batteries over the years. Any of my chargers that will not do balanced multi cell charging...in da trash. At least you have series charging for those as an option. Lithium Storage charge voltage is widely published, no?