You CAN store your Mavic batteries on the charger without damaging them

[CanaanBill]

Agreed, this is an interesting topic and as an engineer, what is said about the slow discharge of the batteries is correct; also the fact that leaving them on the charger makes no difference, given the charger stops charging once a battery is full. But I have offered my drone to the local fire department for SAR and firefighting use and there is no notice when a call is received. So, I would like to have my batteries remain at full charge for when I need to grab my drone and run. There are several ways to do this, with caveats. One way is to have a simple 7-day, AC wall timer that runs for, say 3 hours, to charge the batteries (and controller), then shuts off for, say 3 days, before repeating. That would ensure the batteries stay nearly fully charged, with the caveat that there would be 100+ charge cycles over a year. Does anyone have experience as to a deleterious effect on battery life as a function of number of charge cycles?

 

[brett8883]

Leaving them on the charger for long periods means that any time there is a power interruption to the charger, and the power returns, the battery, or batteries will be charged up to 100%, and allowed to start discharging again according to the settings saved in each battery.

Here in Maine, power interruptions are fairly frequent, and I certainly don’t want my batteries randomly charging and discharging.

Actually the battery manual says to fully charge them and discharge them every three months for optimal battery health anyway.


( https://dl.djicdn.com/downloads/mav...lligent+Flight+Battery+Safety+Guides+(EN).pdf )

 

[CanaanBill]

That's one end of the spectrum, but what's the other—how many charges should a battery accept before its life is affected?

 

[MAvic_South_Oz]

Leaving them on the charger for long periods means that any time there is a power interruption to the charger, and the power returns, the battery, or batteries will be charged up to 100%, and allowed to start discharging again according to the settings saved in each battery.

Here in Maine, power interruptions are fairly frequent, and I certainly don’t want my batteries randomly charging and discharging.

That is one situation where you don't want to leave batteries in a plugged in charger . . . where a power refresh would start charging again.
As many others have posted here, it's good to be in the room where they are charging, as well as having as safe a place as possible to place them while charging.

I like to recharge while doing computer tasks, behind me on a metal tool / workshop trolley.
Thinking of adding a bed of sand in the bottom of the metal tray, maybe an inch of course river sand.

 

[Simmo]

OK, mine went back into the hub, and are now fully charged. Battery lights have stopped flashing. Pressing the button shows 4 lights.
I'll leave them there for a few weeks, see what happens.

 

[MAvic_South_Oz]

OK, mine went back into the hub, and are now fully charged. Battery lights have stopped flashing. Pressing the button shows 4 lights.
I'll leave them there for a few weeks, see what happens.

Take one out as a control measure / base.

 

[Simmo]

Take one out as a control measure / base.

Done Bud. One in, one out.

 

[RayOZ]

OK, mine went back into the hub, and are now fully charged. Battery lights have stopped flashing. Pressing the button shows 4 lights.
I'll leave them there for a few weeks, see what happens.

How will you determine if it works? Are you expecting the charger to trickle charge the battery to maintain 50%? Or that once is goes below 50% the charger fully charges the battery again?
Say both starts discharging, to say 55% and stop. How long do you wait? Were you expecting the charger to start charging again when battery drops below 50%?
I think the best way to actually prove if the charger is continuously maintaining a charge of the battery is to use a smart plug that can monitor the current draw. You get a small base current draw once batteries are fully charged. If you see an increased power consumption after a few weeks, then you can say the charger is actually trying to maintain a charge on the battery.

Personally I don't understand the purpose of this exercise.
1. Keeping the battery fully charge for a long time is bad for the battery. Last thing you want is when you are ready to fly, you find the battery puffed up.
2. Having the battery maintain at 50% is not practical in the sense that you don't want to start flying at 50% battery anyway, so you'll still have to fully charge the battery. I get about 20mins of flight from 100% to 30%. I'll get like 6mins if I fly from 50% to 30%.
3. As per DJI's recommended battery maintenance: fully charge and discharge the battery every 3 months, not keep at 50% charge for 6 months.
4. Continuously charging and discharging the battery seems like a waste of power. Yeah, it's only a few cents to fully charge a battery, but still, a waste of energy.

 

[MAvic_South_Oz]

Personally I don't understand the purpose of this exercise.

You'd be right there Ray, it's probably more to just 'know' for sure what would happen.
Kinda like people climb mountains because they're there

My bet is once a cycle is finished, the charger just remains off, the batteries discharge to the ~ 50% safe level, and remain there.
The only thing that would vary that is a power outage, when it comes back on I'd say the charger would fire up again and recharge the batteries.

That wouldn't be a good thing if not there in the same place due to possible lipo fire, and I'm sure @Simmo would be taking that into account in case that happens during his test.

 

[GadgetGuy]

In my experience, once the hub has finished charging all batteries, it shuts off and stays off. Removing and reattaching a battery causes it to turn back on, as does disconnecting the hub from power and reconnecting it. There is no trickle charge while connected, after fully charging. Batteries will continue to auto-discharge, per the set discharge time period.

Using a 24 hour timer that turns the power off, and then on again, once every 24 hours, will keep all the batteries fully charged and ready for use, by topping off any partially discharged batteries once every 24 hours, and resetting the autodischarge period when it tops off that battery.

Also, to restart/reset the discharge period before auto discharge has commenced, you must fully power cycle the battery on and then off. Pressing the power button to check the charge status no longer resets the discharge period, as it did with Phantom batteries.

 

[Bluesman]

Now I’m confused
So if my batteries are 100 percent charged and I’m not planing on flying for a while, if I put them back on the charging hub but not plugged in, Does it discharge them to 50 percent, or just leave them and they self discharge??

 

[old man mavic]

Now I’m confused
So if my batteries are 100 percent charged and I’m not planing on flying for a while, if I put them back on the charging hub but not plugged in, Does it discharge them to 50 percent, or just leave them and they self discharge??

no the charging hub does not discharge the batteries each individual battery will discharge itself over a period of time one thing that needs to be remembered is each charge cycle is slowly degrading the battery cells chemical reactions that is why they have a finite life span,all lipos loose some charge capacity over time

 

[MAvic_South_Oz]

Now I’m confused
So if my batteries are 100 percent charged and I’m not planing on flying for a while, if I put them back on the charging hub but not plugged in, Does it discharge them to 50 percent, or just leave them and they self discharge??

They self discharge (provided it's not a Mini) when removed from the charger, or left in the charger.
For safety reasons, just remove them as it's safer as described above (in case of power interruption).

I don't charge them after flight, just leave until the night before going out next to charge.
The only exception is if you fly them really low, like say below 15%, best to just give them a little top off then, take of the charger when the 2nd battery light stops flashing and becomes fully lit.
If you finish a days flying and you still have some charged, it's perfectly ok to leave them for the auto discharge.

You can also reset auto discharge to a few days if you like, rather than the default 10 days.
Do this when the drone is powered up, in the battery part of the menu, needs to be done for each battery.

 

[Bluesman]

Ahh.... thank you

 

[GadgetGuy]

Now I’m confused
So if my batteries are 100 percent charged and I’m not planing on flying for a while, if I put them back on the charging hub but not plugged in, Does it discharge them to 50 percent, or just leave them and they self discharge??

The fact that your batteries are on the charging hub is totally irrelevant if the charging hub is not plugged in. The hub can't do anything without power. It's the same as having all the batteries off the charging hub. Obviously, they will self-discharge after the set period of time for discharge, unless they are Mini batteries that do not.

 

[TnDronePilot]

Here I’ve updated the name of the thread to “You CAN store your Mavic batteries on the charger without damaging them”

This has been a good talk and I hope it has been helpful.

Just so you know, months later, this thread is still very helpful to the dummies like me that don't read the manual or scan the forums before panicking. I was about to contact Amazon for a return as I thought there was a serious issue. I have the MA2 Fly More Combo and couldn't understand why all three batteries were 3/4 to 1/2 discharged after fully charging a couple weeks ago. This should be a sticky until battery technology changes. From reading threads on this forum, I learned that even though these are Li batteries, they don't operate like other electronics that use that battery type. I didn't know they "needed" to discharge to prevent swelling. Anyways, thanks.

 

[DanMan32]

Any Li based rechargeable doesn't like to be left at 100% long term, particularly LiPos and particularlyin hot locations. But most applications you use the charge almost as soon as it's complete.

Laptops these days have an option to not charge to 100%. This is a good option if it's plugged in all the time.