Battery Maintenence Question

[Billbrown1982]

Hey guys,

So upgrading from a F450 and not flown that in years but I vaguely remember having to balance charge the batteries and such and make sure they didn't drop below a certain charge level etc etc...

With this drone being a lot more "plug n play" I was wondering what I need to watch out for rather than just charging them when they go flat.

Already read about charging them individually on the first charge ?

 

[CactusJackSlade]

All DJI batteries are "smart batteries" meaning they will discharge to storage level after a few days (this is selectable in the app 3 to 10 days if I recall correctly). For charging nothing to it - plug into DJI charge and let it charge. These are still litium batteries, and I've never had an issue, but don't leave them charging unless you are keeping an eye on them/in the vicinity.

 

[RustyBonz]

Is it healthy to let the charge % go down under 10% or lower? I vaguely recall that rechargeable batteries 'liked' getting a deep charge once in awhile. The 5-day trickle with top off before I fly is what I've been doing. May be my imagination but the discharge rate from about 42% to 25% happens pretty quick/faster than top off to 42%. Have 3 batteries for my M2P each 2.5 months old.

 

[z28lt1]

Battery Care is More Important than You Think - DJI Guides

 

[old man mavic]

the batteries used in the Mavic are a totally enclosed battery and charge balancer built in to each individual battery ,as well as balancing the cells they have over charge protection and a system that counts the charge cycles which are displayed in the app there is also an auto discharge system, but having not seen the specs in the manual yet ,i cant confirm what settings there will be for setting the no of days ,the actual cells of the battery are really just the same as any 3 cell lipo ,and you need to observe the same precautions when handling them dont charge them unattended, keep them from getting to hot, say in a closed vehicle on a sunny day ,and dont leave for long periods at a very low charge

 

[gottahavit]

I never fly my air 1 batteries below 30 percent(usually 40) and never charge them up until a few hours before I fly, all 3 in my fly more combo are still extremely healthy and I get a solid 15 min flying them to 30 percent in calm conditions after 18 months and probably 50 flights per battery. If I fly them below 40% I will charge them to roughly 50% before I store them unless I'm flying again the next day.

 

[swooshdave]

I never fly my air 1 batteries below 30 percent(usually 40) and never charge them up until a few hours before I fly, all 3 in my fly more combo are still extremely healthy and I get a solid 15 min flying them to 30 percent in calm conditions after 18 months and probably 50 flights per battery. If I fly them below 40% I will charge them to roughly 50% before I store them unless I'm flying again the next day.

Why would you charge them to 50% before storage when the batteries will automatically discharge to a safe level?

 

[easyheimer]

Why would you charge them to 50% before storage when the batteries will automatically discharge to a safe level?

Because a safe level is between 40 and 60%

 

[Mousehunter]

Old NiCad batteries tolerate deep discharge well. It was supposedly good as it would keep them from developing a discharge memory. If they got too hot they could vent. LiPo batteries are somewhat more picky. They should never be allowed to fully discharge - it kills them. That said, many have protection circuits that do a decent job at preventing it. They have a slow internal discharge rate. Heat is bad for them, it can cause puffed cells (which should be safely disposed of). I think it is best to store them partially charged in a cool environment. 100% charged and freezing is also BAD. I don’t know how long you can store them without maintenance charging - but I think it is a couple years. But storing a discharged battery for a long period is probably the best way to get them to kill themselves by fully discharging.

Oh, if lipo batteries overheat enough while charging they can go from simply puffing to a rather impressive fire. I assume that DJI puts protection circuits in to prevent this - but coming from an RC background - charging outside in fire bags is encouraged. I also suspect DJI charges there batteries extreamly slowly (good for life of battery and safty). With good cells and a smart charger you can charge some lipo’s up to about 80% capacity in 15 minutes‘ish. Maybe that is why they use fire bags.

 

[Billbrown1982]

Thats great info guys, thanks.

Unfortunately my F450 didn't get flown for easily a couple of years and when I dug it out the other day after getting the bug to finally tackle repairing it, I found all 3 lipo's swollen as hell, which was part of my decision to just get a MA2 instead.

 

[E90RAW]

Is it healthy to let the charge % go down under 10% or lower? I vaguely recall that rechargeable batteries 'liked' getting a deep charge once in awhile. The 5-day trickle with top off before I fly is what I've been doing. May be my imagination but the discharge rate from about 42% to 25% happens pretty quick/faster than top off to 42%. Have 3 batteries for my M2P each 2.5 months old.

I read that you should NOT let LiPo batteries (lithium polymer) go below 3 volts per cell. In RC cars the controller will shut off the battery at 3.2 volts/cell(cars usually have 2 cells or 6.4volts), but in the flying world that cannot happen as it would be dangerous to have planes falling out of the sky. The problem with going below 3.0V is water and heat formation lead to Lithium Oxide buildup internally to the battery on the cathod or anode, which then increases resistance. (I remember chemistry class and placing lithium in a local pond....very explosive when mixed with water or O2-group 1 alkali metals all can do this). This leads to further heat buildup and eventual failure of the battery. At best it reduces the life of the battery from 150-250 cycle range, worst case scenario is swelling and explosion. This is also why you should only charge when you are nearby. Any swelling in the batt case means LiOxide has occurred and get rid of the battery.

 

[Jetdriver100]

The batteries seem to be a hot topic all the time. I read so many different scenarios on how to keep them in good shape. Not even sure what to believe or not anymore? On AirData.com. they say to empty the battery every 20 flights to below 8% to deep cycle the battery. Charge it back to full then use as normal until the next 20 flights. I alway fly my battery down to 15 to 20 % and have no issues. I let it cool for hours before I charge it. I put a timer on for 21 minuets and take it off the charger. That lands it between 45 to 60 %. I then go on to my next battery. 4 in total. and cycle them.
The battery thing seems almost stressful

 

[Jeff A]

<SNIP>I let it cool for hours before I charge it.<SNIP>

Or, you could just put it on your porch for 5 minutes.