OK. Same hill test on 15S lipo.
Max speed: 36mph
Average speed: 24mph
Lowest sustained speed ( while hill climbing ): 31mph
Amp hours used: 3.9ah.
This motor, voltage, and controller combination eats hill for breakfast and asks for seconds.
Average speed was not much higher because i had to keep slowing down to go around turns, slowing down on sidewalks, and dodging road hazards. And the stoplights on the hill contributed to a smaller gain in average speed here.
There were a few problems:
+ I was having problems with stalling from a dead stop; I'd hit the throttle and it would literally not do anything. Perhaps the infineon has some kind of internal stall protection. This happened only on inclines. I know my LVC was not kicking in..... very strange. Only happened at higher inclines. Doesn't happen on 10S.
+ The controller was quite hot. The batteries were warm-hot. The 14ga battery wires were even hotter. My bad on that...
+ The motor generates a kind of grinding resonance / ringing type sound at particular speeds at this voltage. Must be the sound of the stock nylon gears crying for mercy. How terrible of me to ignore their screams
This doesn't occur on 10S though.
+ When i hit the throttle, i can definitely hear the keyway clanking inside the motor. I can feel the jolt of torque that evens out. This is very pronounced at 15s, and not very noticeable at 10S.
+ The bike is very difficult to maneuver around obstacles above 25mph. Dangerous, is the word i would use to describe hitting a dip at 32mph and bouncing off your seat as a result. I believe i need a dual suspension bike with speeds like this. I think i will stick to 10 or 12S and call it a day.
I am now realizing that the 9FET is not meant for a sustained 2300-2500w peak.
One other note: at this power level, it is pretty much futile to pedal. I noticed that the difference in speed between me pedaling uphill and not is around 1mph.
at lower speeds, pedaling helps a little, at higher speeds, pedal gear ratios and the fact that the motor has 10 times the power you do really work against you.
But dear lord it is stinking fast.
Back to 10S-12S i go. Less abuse on the entire drivetrain, less problems, safer, etc etc.