- Joined
- Sep 28, 2015
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Probably, but how they are factoring in battery temperature confuses me. Even in so-called cold-weather conditions the battery internal temperature starts at the starting (room) temperature and does nothing but increase, and increase fairly quickly, over the course of the flight. Below is a graph of my battery temperature from my tests today in 30-something weather -- the decrease in performance started around 5 minutes into the flight, and temperature of the battery was over 80 degrees F by then. By the end of the flight when performance was at its worse the battery temperature was over 100 degrees F. Even when I've flown in sub-zero (F) weather I get a similar temperature curve.After reading a lot of threads on the new firmware upgrade and prior "sky fall" incidents, I think that cold makes the voltage drop of the battery worse when it is under heavy load such as when revving up the engines by throttling upward aggressively. When batteries are older or lower on charge the voltage also drops severely when under heavy loads. So what DJI seemed to do is monitor battery temperature and calculated voltage to change throttle load limits (decrease them) in times of low temperature and lower battery life (60% and lower perhaps). This would decrease the voltage drop and hopefully keep it above 12 volts (3 per each Lipo cell X 4 = 12v). I also hope they erred on the side of safety and eliminated the battery shutoff. Who cares about damage to a battery over time; this better than a crash that bricks a phantom and its battery!
Oh and let me add that even at end of flight, about 30% remaining during this flight, battery voltage was around 3.5 to 3.6 V -- a little ridiculous to be throttling so much when the cells are well above 3V still.