Actually voltage is available in the data stream. I could display it, but it fluctuates every few ms.
Would you know which voltage to store at and when / how to measure? I don't.
I have never read any conclusive data about this. I mean something backed by true scientific papers, not just some amateur experiments. I think early in the days of LiPo someone came out with 60-80% and this has been repeated thousands of times
Very few know what 60% refers to.
Is it 60% of the voltage spread between empty and full voltage? What exactly are the empty / full voltage thresholds?
Or is it 60% SoC? Is SoC a linear function of voltage?
And how does all this apply to the specific HV LiIon batteries used for
Tello ?
In the end I just decided there is too many variables so I just follow my gut feeling.
Never store empty.
Never keep in charger for more than a couple of hours.
Never ever leave the battery in the drone more than a day ro two
Never charge when still warm from last use
I store my flight batteries between 30-100% as
Tello reports. I fly until forced auto landing kicks in, and typically give them a quick charge for 20min or so. My main flight batteries are 1 year old and still good for 10+ min.
I have a couple of batteries I use for development with
Tello either flying or sitting on a fan.
These are abused to the maximum extend possible: Typically discharged until
Tello shuts off at 0% they are often stored discharged at 0% for several days, or they might be charged right after discharge when still warm. During development I use the first one I can find that has some juice, and plug in some other without keeping track of anything.
Whatever it takes. I just don't care at all.
The oldest is 1.5 years old and is still good for 6-7min.
Bottom line: relax. The batteries are mostly indestructable, the only thing that kills them is to keep the batt in the drone for weeks