OK. I had a about 45 mins before going to work so I decided to practice my RTHs. Of the 6 tests, only 4 returned home as expected. One was a few feet off which I had to land manually. The last one was not good which I will describe later.
Ground conditions:
- Flat, grassy lawn 400 ft x 80 ft with trees around the edges
- Very light wind
- Sunny - 2:30 pm
Flight sequence:
- Battery was at 100% when started
- I was flying GPS with default mode ("Sports" mode OFF).
- Each time I made sure I had at least 16 satellites.
- Took off from a landing pad with well-marked design, went straight up to 30 ft and hovered for about 7 - 10 seconds for the MP to record landing position
- Flew away from base no more than 10 ft laterally and up to about 50 ft, and then hit RTH
- 4 landed perfectly, one was a few feet off (had to land manually as mentioned above)
OK, now, the last landing:
- Battery level was at 20% when I attempted the last RTH. I would never fly below 20% but since the MP was only a few feet from me, I decided to try RTH one last time since the previous one was not accurate.
- Within seconds - and only 2 ft to ground, battery dropped to 11%, and then the whole thing shut off. The MP went straight down to the grass. My heart dropped to the ground faster than the MP...
- Fortunately, there is no damage to MP thanks to the grass and extra leg extensions.
Battery level should not drop from 20% to 11% to zero in 2 seconds...
Since I am fairly new at this (about 6 hrs of flight time), please feel free to diagnose and provide me with guidance. I understand that RTH is used mostly in emergency situations, but I am new and would like to stay on the safe side. Any advise is greatly appreciated.
Thank you and keep on droning!