blackcrusader Posted at 2018-8-18 18:25
Take the battery out of the drone.  Power it on and leave it overnight to drain.

It will drain and then shut off.  Let it cool down.  Then you can charge it up again.

is it the same with have it discharge by using the drone until 8~10%? then cool it down then charge it?

Mark The Droner Posted at 2017-3-17 05:37
I have two batteries that like to auto-land early.  One lands at 27%.  There is no reason I can see for it to do this other than it's slightly swollen.  The other battery lands at 24%, but on that one, the percentage drops like a stone along with the mAh as it lands.  Last time I tested it from a height of about 10 feet, it only takes about 30 secs to drop down from 24% to 7%.  Needless to say, I don't make distance runs with either battery.

Mark, how many cycles do you have on the battries you are talking about ?

SparkYeL Posted at 2018-8-18 20:56
is it the same with have it discharge by using the drone until 8~10%? then cool it down then charge it?

Yes this is the same, here and thre is written you hsould do that every 20 charging cycles. If this is a myth I dont know but it can't hurt the batteries so I do it.

Ray_Drone_Pilot Posted at 2018-8-18 23:09
Yes this is the same, here and thre is written you hsould do that every 20 charging cycles. If this is a myth I dont know but it can't hurt the batteries so I do it.

yes i also saw that every 20 cycles. after thedeep cycle, can i charge it to 100% after a week? since i will not be able to fly it all tomorrow. i am planning to drain my batt until 8~10% and i will store it until next weekend then charge it by next weekend, is that okay?

Sayhelloforme Posted at 2018-8-18 21:48
Mark, how many cycles do you have on the battries you are talking about ?

Wow - this was a while back...

The former was a Venom aftermarket and had 36 cycles.  The latter - another aftermarket had only 12 cycles.  They were both P2 batteries.  But back then, Venom was making really good P2 aftermarkets.  It swelled up a bit because I left it fully charged for too long and I didn't know the P2 batteries don't have the auto-discharge feature.

Here's a very boring vid of the P2V auto landing at 27% (shoot ahead to 14 mins)

Mavic~Spark~yeL Posted at 2018-8-18 23:55
yes i also saw that every 20 cycles. after thedeep cycle, can i charge it to 100% after a week? since i will not be able to fly it all tomorrow. i am planning to drain my batt until 8~10% and i will store it until next weekend then charge it by next weekend, is that okay?

The best level for long term storage of these batteries is at approximately half-charge.  If you are planning on flying it in a weeks time, I'd charge it up fully before storage, then top it up again immediately before flying.  Leaving a battery fully charged or fully depleted for long periods will damage it and cause it to swell.  The intelligent battery has circuitry built-in to address this.  It will auto-discharge itself down to a safe level after a pre-set time (I think it is 10 days by default) but you can change that in the app.  Some people recommend setting 2 or 3 days before it auto-discharges.  Never assume the battery is fully charged because you put it away with a certain charge -- you can't always be sure the auto-discharge hasn't kicked in while it was in storage.  Always top it up and confirm it is at 100% before flying, otherwise the reported capacity in the app could be mis-reported and it could shut down early, leading to a lost aircraft (plenty of examples on this forum).

The 20-cycle deep discharge thing is a bit of a myth.  It is really only useful if you only partially drain the battery each time before recharging it, and you do that all the time.  It can cause the battery to mis-calibrate the level required to report "empty".  If you use it and discharge it down to 10-20% in normal flight once in a while, it should do the same thing.

Mark The Droner Posted at 2018-8-19 04:02
Wow - this was a while back...

The former was a Venom aftermarket and had 36 cycles.  The latter - another aftermarket had only 12 cycles.  They were both P2 batteries.  But back then, Venom was making really good P2 aftermarkets.  It swelled up a bit because I left it fully charged for too long and I didn't know the P2 batteries don't have the auto-discharge feature.

Oh, I did just notice the date. I watched the video. Do you know if  balancing cells in batteries are possible?   I have a power extra battery and cell one seems lower than the rest. I don’t use it anymore but just wondering.

Some people claim it's not possible.  My experience is, it's sometimes possible depending on the battery, but the fix will probably be only temporary.  My position is, if you're going to retire the battery anyway, why not try to balance the cells?  Maybe you'll get lucky.  To do that:

1)  Fully charge battery

2)  Discharge battery to whatever level you think is correct (opinions vary but for a P3 battery, I think 5% is a good target)

3)  Fully charge battery.

Then you'd check the cell balance.  

Mark The Droner Posted at 2018-8-19 06:35
Some people claim it's not possible.  My experience is, it's sometimes possible depending on the battery, but the fix will probably be only temporary.  My position is, if you're going to retire the battery anyway, why not try to balance the cells?  Maybe you'll get lucky.  To do that:

1)  Fully charge battery

Thanks so much Mark. I’ll try it.

Sayhelloforme Posted at 2018-8-19 13:27
Thanks so much Mark. I’ll try it.

Good luck...

Mavic~Spark~yeL Posted at 2018-8-18 23:55
yes i also saw that every 20 cycles. after thedeep cycle, can i charge it to 100% after a week? since i will not be able to fly it all tomorrow. i am planning to drain my batt until 8~10% and i will store it until next weekend then charge it by next weekend, is that okay?

Thats not a good idea Mavic Spark Yel. Better to discharge till 8% and  after let it cool down and charge till 50% or so