Batteries: What constitutes a charge?

DJ Wes · Aug 27, 2019

We all know that the DJI Go (4) app shows how many times a battery has been charged. The implication being that the number of charges is related to the remaining battery life. With older DJI products (P3, P4, Inspire), a “press and hold” of the battery power button for 5 seconds would result in the battery lights showing the remaining battery life. Once the battery life reaches 0%, the battery can no longer be used. This function no longer exists for the Mavic batteries.

In an effort to keep my usage equal between all of my batteries and also to better understand what constitutes a charge, I started to keep a log of every time I charged a battery and every time I flew. I am currently doing this for all of my batteries. After capturing this data for some time, I have found that what constitutes a charge is not really obvious. However, I have made a few observations which I will share at the end.

Here is the charging and flight log for one of my Mavic 2 batteries:

Date	Event	Times Charged	Usage
4/9/2019	Charge to 100%
4/9/2019	Fly to 75%
4/16/2019	Fly to 14%	3	86%
4/16/2019	Charge to 39%	3
4/20/2019	Charge to 100%	4
4/21/2019	Fly to 12%	4	88%
4/21/2019	Charge to 100%
4/21/2019	Fly to 25%	5	75%
4/28/2019	Charge to 50%?
5/5/2019	Charge to 100%	6
5/5/2019	Fly to 18%		82%
5/5/2019	Charge to 57%	7
5/10/2019	Fly to 15%	7	42%
5/10/2019	Charge to 50%?	7
5/12/2019	Charge to 100%	7
5/12/2019	Fly to 46%	7	54%
5/26/2019	Charge to 100%	7
5/27/2019	Fly to 52%	7
6/9/2019	Fly to 28%	8	72%
6/11/2019	Charge to 98%	8
6/11/2019	Fly to 75%	9
6/12/2019	Fly to 31%	9	67%
6/16/2019	Charge to 98%	9
6/16/2019	Fly to 37%	10	61%
6/16/2019	Charge to 100%	10
6/18/2019	Fly to 42%	11	58%
8/11/2019	Charge to 100%	11
8/11/2019	Fly to 60%	11	40%
8/17/2019	Charge to 100%	11
8/17/2019	Fly to 38%	12	62%

Observations:

“Times Charged” is really counting usage cycles. Most (if not all) times I have observed that the number of charges is incremented in DJI Go during or after a flight and not at the end of a charge.
“Times Charged” is NOT incremented when one or more charges add up to 100%. Therefore, a simple charge of 0 to 100% is not necessarily counted as a “Charge”. Note that the number of charges was shown to be 7 after more than 144% of usage.

Even after collecting and analyzing this data, it is still not clear to me what constitutes a charge. I am open to any information to help clarify exactly what “Times Charged” is counting. Perhaps DJI is using “fuzzy” math.

Mossiback · Aug 27, 2019

I cannot answer your question, but I would assume that whatever constitutes a charge works the same for all batteries. If correct, then the charge count would be relative to their use even though not exactly accurate.

As for keeping your usage equal between all your batteries, you could just number them and use them in order.

Magilla Gorilla · Aug 28, 2019

The way I understand it is that the battery logs one charge cycle (or times charged) after seeing a cumulative charge of 100%. So you fly a battery down to 30 % and recharge to 100%. You have added 70% . The next flight you only fly down to 70%. When you recharge to 100% now you have added 30% and a cumulitive of 100% and 1 charge cycle.
BUT I see that your observations don't support this theory.
Interesting! Will follow this thread.

Inspirephil · Aug 28, 2019

It’s all very confusing and trying to keep up with how many cycles are on each battery is futile.

Bigbird48 · Aug 28, 2019

I agree with Phil, I'll just keep charging and flying till the battery doesn't work anymore then get a new one. I tried keeping track and numbered the batteries but things happen and you grab the wrong one or put it in the wrong spot in the case and next thing ya know there all out of whack again LOL

Magilla Gorilla · Aug 28, 2019

As Bigbird48 said use em till they don’t work.
However, I like to keep track of usage, having an Aviation Maintenance background.
Using the cycle counter in the Go4 app I have managed to keep 4 MPP batteries at the same count (currently 94 charges each)
Using a test method learned from the Phantom Pilots Forum, (not sure if it pertains to Mavic batteries) I push and hold the battery switch for 5 seconds. Battery lights illuminate to show remaining battery life. All 4 of mine have 3 solids and one blinking. This would indicate more than 75% and less than 100%.
Anyone have a comment on this.