Signs of battery life ending

John Locke · Jul 1, 2016

I've been flying Phantoms for a year now. I've got over 200 flights on my P3P, but my 5 batteries have less than 50 charges, and they are still performing great. My P4 is still below 20 charges each on the 3 batteries I have, no problems whatsoever.

I'm sure there are others with more air time than me, so I'm hoping to find out if anyone has worn out a battery. I haven't seen anyone mention this yet, I didn't quick search but found nothing. Has anyone seen a DJI battery swell up or simply won't last as long on a charge? If so, how many charges were on the battery, and what was the symptom? Should we be looking for battery swell at 50 or 100 charges, etc? What are the limits you use to decommission a battery when the time comes?

If the battery is swollen, it's obvious it should be decommissioned, simple decision, but I haven't heard anyone with this issue yet. Does swelling happen very often?

If the battery flies only 13min instead of the normal 16 to 18min (P3P), at what point of degraded battery duration would you decommission the battery if it's not swollen? 75% of normal?

kevinm · Jul 1, 2016

I'm not 100% on this but 50 cycles seems to be getting "up there" in terms of cycles. If you're also seeing performance degradations then it's smart that you're thinking about retiring the batteries.

One of the ways to diagnose something wrong with your battery (in addition to puffing) is to look at the voltage deviations between each individual cell during the flight. It's normal to have some voltage deviation but if the deviations get too large and/or reach a threshold frequency, it might be a sign you should retire the battery.

Your DJI generates flight logs for each flight that detail this battery information. Healthydrones.com is a useful tool for analyzing the batteries.

I'm also part of a team building battery analytics software. You can sign up to be part of our beta at nvdrones.com!

Fourman · Jul 1, 2016

One of my best performing battery has 50 cycles. I think it is more how hard each cycle is not really the counts.

Mark The Droner · Jul 2, 2016

I agree with the OP. I have not seen anybody who has posted they've reached the end of their battery life expectancy on a battery that wasn't abused in some way.

John Locke · Jul 3, 2016

kevinm said:
I'm not 100% on this but 50 cycles seems to be getting "up there" in terms of cycles. If you're also seeing performance degradations then it's smart that you're thinking about retiring the batteries.

One of the ways to diagnose something wrong with your battery (in addition to puffing) is to look at the voltage deviations between each individual cell during the flight.
!

Seems I read somewhere from DJI the life expectancy is 200 cycles, am I wrong?. I do monitor cell deviations but so far all is ok, but some are close to being outside the max tolerance. Although HD recommends what's normal for deviation, is there a limit you'd recommend for max deviation that warrants retiring a battery, even though flight duration is ok?

kevinm · Jul 5, 2016

Seems I read somewhere from DJI the life expectancy is 200 cycles, am I wrong?. I do monitor cell deviations but so far all is ok, but some are close to being outside the max tolerance. Although HD recommends what's normal for deviation, is there a limit you'd recommend for max deviation that warrants retiring a battery, even though flight duration is ok?

I wasn't sure about the life expectancy but if it says 200 then I was wrong about 50 being towards the upper limit. That being said, pilots have varying opinions about what the "upper limit" is - some agree with it and some don't.

We haven't done enough internal testing yet for me to say I know anything more than what HD recommends. Hopefully this will change in the future as we do more testing with different batteries