I could really use the forum's advice on why my Hydra 120 ESC caught on fire after 10 minutes of light use. It was the last run of the year and I was trying out my new LiPo batteries so I never went over 80% full throttle. In the beginning of the run, the Fall leaves got caught on the prop, so I slowed down several times and went in reverse slowly and it freed up the prop. So, it was a noncontinuous run ranging from very slow, with reverse operation, and to about 40mph towards the end of the run until the ESC went "Poof" and was charred beyond recognition. Just before the ESC went, the boat had slowed down. After retrieving the boat, I saw that the prop and the prop nut were missing and must have just come off just before the ESC caught on fire. (Not sure if I tightened prop well). But, the motor seems fine. Water cooling was also running smoothly.
Here's my set up:
30-inch Cat Hull
Feigao 8XL (2084kv) - New motor, seems fine.
Hydra 120Amp ESC - used only 2 times.
Hextronic 4S2P LiPo 15-25C 4100mAh (8200mAh total) = 123 Amps
All Speedmaster HW, direct drive.
I know I was running at 123Amps, that's why I ran it cautiously and didn't go over 80% throttle. If anything, I thought the motor would go since it's rated at 83Amps. Also silly, not sure if I tightened the prop after switching it?
I am trying to figure out why the ESC burned up? Because of the prop coming off? -OR- Because I run a high Amp Lipo under partial throttle conditions?
How should I run a boat under partial throttle conditions, should I have used the Hydra 240 instead?
Believe me, I don't want to make this costly mistake again. With my friend manning the lake, I had to go back home to get my raft, which was still in the box. By the time I got back to the pond, it was totally dark by 6pm, temperature was 43 F, and the boat was barely visible the middle of the pond 500ft away.