I'm used to disconnect batteries in RC toys to make sure that there will be no drain that can discharge or disbalance cells in battery pack. I'm reading that "battery switches off after 20 minutes of inactivity" and there are smart circuits (in battery) that I can not unplug anyway so I understand that it should be safe to leave battery in AC but maybe after auto-discharge? How much heat is generated and how long does it take (to auto-discharge to 60% after 5 days of idle)? It would be nice to have option recharge to storage or full capacity, like modern smart chargers can do...

What is Your experience with smart batteries for best performance and lifespan?

It's fine for short term storage (in the bag to the a flight location) but not advised for long term - the batteries become quite warm during the auto discharge process so it's not best to have them in the drone. After the discharge is complete or if stored at around 40-50% I still wouldn't leave them in the drone for prolonged periods of non use.

Note point 3 from the DJI safety guidelines:

Hello there virtual. Thank you for reaching out and for the inquiry. The DJI Mavic Air 2 has an Auto-Discharging function to prevent the battery for swelling, the battery automatically discharges to 96% of the battery level when it is idle for one day and automatically discharges to 60% of the battery level when it is idle for 5 days. It is normal to feel moderate heat being emitted from the battery during the discharging process. For additional reference I will post a list of the intelligent flight battery safety guidelines. In addition it would be best for you to store your DJI Mavic Air 2 Intelligent Flight Batteries on a DJI Battery Safe Bag. The DJI Battery Safe Bag offers reliable storage, and transportation for batteries. It can effectively mitigate damage from combustion, reducing the possibility of igniting surrounding objects. Thank you.

A J Posted at 7-8 13:11
It's fine for short term storage (in the bag to the a flight location) but not advised for long term - the batteries become quite warm during the auto discharge process so it's not best to have them in the drone. After the discharge is complete or if stored at around 40-50% I still wouldn't leave them in the drone for prolonged periods of non use.

Note point 3 from the DJI safety guidelines:

I didn't realise they didn't recommend more than 200 cycles.  That sounds expensive.

DAFlys Posted at 7-9 01:29
I didn't realise they didn't recommend more than 200 cycles.  That sounds expensive.

Yeah, four MA2 batteries bought brand new at full retail in the UK is £420. 800 flights doesn't sound too much for that sum but with each flight lasting, on average, 25 minutes thats 333 hours of flight time and around 1,665 miles in total flight distance based on an average of 5 miles per battery. But yeah, that is nearly two quid a flight just for the cost of eventually replacing the batteries. If you properly look after them I think you can stretch out more than 200 cycles.

Thank You for replys, so I would be leaving battery in the drone only for less than a day, mostly when transported to or from flying spots (BTW Mavic Mini hub is handy to store all 3 batteries in Fly more combo case). During the auto discharge process would be good to have batteries in ventilated area (out of the bag) with constant room temperature, no direct sunlite ect.

Stephen, I believe that it would be great if there was option to charge battery to storage voltage (3,8V/cell) or full voltage (4,2V/cell). Auto discharge function wouldn't be needed, no additional heat emitting, faster battery maintenance. Inspiration for next generation of drones?

A J Posted at 7-9 01:37
Yeah, four MA2 batteries bought brand new at full retail in the UK is £420. 800 flights doesn't sound too much for that sum but with each flight lasting, on average, 25 minutes thats 333 hours of flight time and around 1,665 miles in total flight distance based on an average of 5 miles per battery. But yeah, that is nearly two quid a flight just for the cost of eventually replacing the batteries. If you properly look after them I think you can stretch out more than 200 cycles.

I suppose it compares with the cost of nitro for other RC models.

virtual Posted at 7-9 01:42
Thank You for replys, so I would be leaving battery in the drone only for less than a day, mostly when transported to or from flying spots (BTW Mavic Mini hub is handy to store all 3 batteries in Fly more combo case). During the auto discharge process would be good to have batteries in ventilated area (out of the bag) with constant room temperature, no direct sunlite ect.

Stephen, I believe that it would be great if there was option to charge battery to storage voltage (3,8V/cell) or full voltage (4,2V/cell). Auto discharge function wouldn't be needed, no additional heat emitting, faster battery maintenance. Inspiration for next generation of drones?

Thats what I do. When I return from flying and the batteries have cooled I charge each one separately without the hub and as soon as the third LED starts to flash (50% charge) I switch off the charger and put the battery in the safe bag. For reference it takes about 20-25 minutes to charge from 15% to 50%. Thats a good enough % to store the batteries without relying on the auto discharge and when you are ready to recharge them to full using the hub it takes about an hour per battery from 50%-100%.

DAFlys Posted at 7-9 01:43
I suppose it compares with the cost of nitro for other RC models.

It's all relative mate - DJI drone batteries are not cheap to put it mildly. I remember paying £191 for a TB48 battery on my Inspire 1 V2 - and they lasted around 15 minutes per flight. So the MA2 batteries are quite reasonable considering.

A J Posted at 7-9 01:46
Thats what I do. When I return from flying and the batteries have cooled I charge each one separately without the hub and as soon as the third LED starts to flash (50% charge) I switch off the charger and put the battery in the safe bag. For reference it takes about 20-25 minutes to charge from 15% to 50%. Thats a good enough % to store the batteries without relying on the auto discharge and when you are ready to recharge them to full using the hub it takes about an hour per battery from 50%-100%.

I'm using this method for Mini batteries as well but the question is how balaced are cells in battery if the charger is unpluged at 50%. Lithium charging programs use high constant current for the first half (that's why the first half is recharged faster) and lower current with constant voltage with balancer function to cut-off each cell at certain voltage at the end of charging process (4,2V for fully charged cell or 3,8V in storage mode). That's why the storage mode is handy as it leaves battery with perfectly balanced cells and the more cells in battery the more important is to keep them balanced.
I use non-smart lipos for ages but smart battery is new to me, so I want treat them right. BTW With proper maintanance they can be usually used more than 200 times from my experience.

virtual Posted at 7-9 03:17
I'm using this method for Mini batteries as well but the question is how balaced are cells in battery if the charger is unpluged at 50%. Lithium charging programs use high constant current for the first half (that's why the first half is recharged faster) and lower current with constant voltage with balancer function to cut-off each cell at certain voltage at the end of charging process (4,2V for fully charged cell or 3,8V in storage mode). That's why the storage mode is handy as it leaves battery with perfectly balanced cells and the more cells in battery the more important is to keep them balanced.
I use non-smart lipos for ages but smart battery is new to me, so I want treat them right. BTW With proper maintanance they can be usually used more than 200 times from my experience.

On the MA2 I find all three cells are perfectly balanced on all four batteries at 3.85v per cell. At 40% they will be around 3.8v.

A J Posted at 7-9 03:57
On the MA2 I find all three cells are perfectly balanced on all four batteries at 3.85v per cell. At 40% they will be around 3.8v.

Good to know!

virtual Posted at 7-9 04:20
Good to know!

You're welcome

First flights at summer temperatures 25+°C for me today, no sport mode. I haven't checked app numbers but battery was warm, I would guess 40°C when landing, it is definitively good to unplug the battery and leave it in the shaded place for a while (before packing). BTW That cooler at the bottom was less warm than during fw. update on the table at home. MA2 is great aircraft!