Massive Battery Drop

sar104 · Jan 3, 2020

DanMan32 said:
You might also recall my comment about that update as a bandaid and inferred admission of a problem with the early batteries that DJI doesn't really want to do right about.

Now you mention it - yes - I do.

Cjuarezr · Jan 3, 2020

It appears some of my info was mistaken by either my moment confusion or the app just had my wrong battery percent. I took off apparently with 84%, I thought it was 100%. Here is the flight log:

DJI Flight Log Viewer | Phantom Help

Upload and view DJI Phantom, Mavic, and Spark flight logs online

www.phantomhelp.com

- There is one strange thing. In the log, the battery percentage doesn't change, but in the app it gave me 0% battery and it started to beep like crazy.

Cjuarezr · Jan 3, 2020

sar104 said:
Only because once the battery has entered the self-discharge cycle the initial reported battery level is completely unreliable. But that wouldn't have happened in just a couple of days. Can you post the flight log - that will show the cell voltages during the flight.

How to retrieve a TXT log: DJI Flight Log Viewer | Phantom Help

I already posted it.

sar104 · Jan 3, 2020

Cjuarezr said:
It appears some of my info was mistaken by either my moment confusion or the app just had my wrong battery percent. I took off apparently with 84%, I thought it was 100%. Here is the flight log:

DJI Flight Log Viewer | Phantom Help

Upload and view DJI Phantom, Mavic, and Spark flight logs online

www.phantomhelp.com

- There is one strange thing. In the log, the battery percentage doesn't change, but in the app it gave me 0% battery and it started to beep like crazy.

The 84% battery level in the PhantomPilots display is not correct - it's a known issue. You started at 95% and the cell voltages dropped rapidly during a 25 second period of full throttle. When cell 4 fell to 2.6 V it triggered the battery level to drop to zero at 42 seconds.

Had you charged the battery recently before this flight, or had it been sitting fully charged for a while?

Cjuarezr · Jan 3, 2020

sar104 said:
The 84% battery level in the PhantomPilots display is not correct - it's a known issue. You started at 95% and the cell voltages dropped rapidly during a 25 second period of full throttle. When cell 4 fell to 2.6 V it triggered the battery level to drop to zero at 42 seconds.

View attachment 89672

Had you charged the battery recently before this flight, or had it been sitting fully charged for a while?

I had it charged since a day or two before if I don't remember wrong. I don't think that was the problem since I did the same thing (full throttle up) with my other batteries. I charge them all at the same time with the charging hub. The only difference was that when I took off with my other batteries, I hovered for a while checking the temperature (so it would heat up). Once it was about 25-30°C, I went full throttle up. It might also be important to note that I left my drone in the car the day before. At night it got like -3°C outside, so when I first started the drone the batteries where about 11°C.