I have been having a heat problem with the motor.
After the first decent run i gave the truck i thought the temps of the motor\ESC\battery where all good. I didn't see a motor temp above i think it was 38c on that run. Ambient was about 18-19. Slipper gearing was 16\58 (mod 0.8).
scriptasylum calcs were
Max speed: 44.55 mph (71.56 km/h)
Total reduction ratio: 11.68056 : 1
At the end of the run i stripped the delrin mod 0.8 spur so subsequent runs are mod 1.
The next run (the one the video was shot on) i didn't check temps except by using my hand. Wasn't paying much attention but i can remember the motor feeling quite warm to the touch. Slipper gearing was 13\46
Calc
Max speed: 45.64 mph (73.31 km/h)
Total reduction ratio: 11.40171 : 1
The run ended with the pinion coming loose and somehow i managed to lose it
So next run was a short one after a day at work. Used the 14t pinion i had and checked motor temp towards the end as i though it might be slightly overgeared(ie too high a top speed). Motor temps were around 60c and ambient probably ~17c.
Max speed: 49.15 mph (78.95 km/h)
Total reduction ratio: 10.5873 : 1
So today i did 4 runs to try and find out what was happening. Ive always read that in an overgeared system (ie too high a top speed) the ESC will run hot and if its really overgeared motor\ESC\battery will all get hot. After today i'm pretty confused about that.
Motor: Tekin T8 4038 1550kV
ESC: Tekin RX8 with fan
Battery: HK Flightmax 5s 5800mAh 30C
Truck weight: 200-300gms lighter than a stock flux. About 3722gms without wheels\battery\body.
Run 1 - confirm heat issue with 14 pinion
Slipper gearing: 14\46
Ambient temp: ~18-20c
Motor temp max: 61c (stopped at this temp)
ESC temp: 38c (fan coming on)
Battery temp: 33c
Run 2 - change to 15 pinion
Slipper gearing: 15\46
Ambient temp: ~18-20c
Motor temp max: 62c (stopped at this temp)
ESC temp: 39c (fan coming on)
Battery temp: 34c
Run 3 - change to 20 pinion (obviously way overgeared)
Slipper gearing: 20\46
Ambient temp: ~18-20c
Motor temp max: 71c (got to that in about half the time of prev runs)
ESC temp: 41c (fan on a lot)
Battery temp: 36c
Run 4 - back to 14 pinion but with sensor cable pulled out of ESC ie forced sensorless
Slipper gearing: 14\46
Ambient temp: ~20-22c
Motor temp max: 61c (stopped at this temp)
ESC temp: 39c (fan coming on)
Battery temp: 34c
Some things i've checked
- drive train moves freely with pinion off motor.
- slipper mesh is good. spur can move slightly back n forth without moving pinion.
- thought maybe sensored mode was permanently engaged. have read sensored systems can run hotter. so did the forced sensorless run. AFAIK with the cable plugged in the system runs in dual mode, sensored at low speed and sensorless at higher speed.
- wheel\tire combo used for all runs was close to 300gm per wheel which is same as stock weight.
- highest slipper temp i checked was 41c. thought it might have been hot and transfering heat to motor somehow.
- ESC settings all seem ok, haven't changed timing from default. It's running in brushless delayed reverse mode with no current limit.
So i'm not sure what to try next. I not sure why temps were so good on the mod 0.8 run, i was taking it a bit easier and there was no grass.
Total reduction is quite low compared to stock but i am running a much lower kV motor. I would have thought gearing for around 45mph would have been reasonable for that motor with 5s?
Any suggestions\comments much appreciated, cheers.