did the "run them flat" worked?
I had exactly the same problem.
Today It even fell out of the sky.....I had a warning at 30%, I started the landing and within the minute it fell down to only 8% and it looked out of control just above the water.....I Managed to get i down any way, but controls did not work properly. Around 1 meter above the ground it just came down hard and tumbled....
Why doesn't DJI solve this battery issue??
Hi Phantom Bas
Thanks for asking mate. I was sorry to hear about your problem. What I did was to put them on charge, bearing in mind that they had been left in a cupboard for 3 months although the battery was reading 75% in reality I think it must have been a lot lower than that. I did fly my bird afer charging and everything seemed to be ok? So far!!!
There have been several threads about this issue on the forum. My P2V was doing this last year.
One time I had sent it on a Ground Station flight over some wooded property, where it was out of my sight and control for a few minutes. It had just come back into sight with about 50% battery remaining when the klaxon sounded and it started to auto-land right over some 100' trees. I was able to override it and steer to a safe landing. Had this happened a few seconds earlier, before I could see it and regain control, it would probably still be in the trees.
I sent it back to DJI in November for this issue. They replaced the battery and one motor. Not sure exactly how that fixed it, but I haven't had this issue since.
I have noticed when checking my Flytrex data that even known good batteries can have very erratic voltage levels. For instance when you do a hard climb, the motors demand more amps. With some of my older batteries the voltage drops quite a bit doing some maneuvers that spool up the motor speeds. I am almost certain that I had an auto land incident because of this. I didn't let it auto land and flew it on home without incident. I have been keeping a close eye on that particular battery when flying to make sure I don't have any more exciting incidents. But I have had this message pop up a couple times lately, "Not enough power to Return Home" but in reality I was able to fly it home. I think it is because as batteries age, they are less able to cope with higher amp demands causing premature low voltage alarms. Meanwhile I do take precaution and land asap whenever I see anything like that happening. The battery I suspect as my worst one only has about 50 cycles on it, even though I have been very careful with it's care and feeding. It still shows about 88% life left which is a result of it's internal resistance rising with age. That one should still be under warranty but I haven't had any luck dealing with DJI in the past, I don't expect that will change.
Iv'e had similar problems from charging batteries and not using them right away.
DJI reccomends as well as general information on charging and storing Li-po batteries to store at 50%, and use right away when fully charged. Both times ive had this issue was from using stored charged batteries past about 10 days. Read more here