alexinter7

Ok so i was running my on-road car at the track, im new to rc so i was going full throttle and braking a lot, my esc got really hot and now the car wont go, the motor just twitches so i got to reading and researching and i read something about if you drive full throttle and brake a lot the esc gets "voltage spikes" is this true? How can i avoid it next time? Oooh by the way its a sensorless setup, flux vapor esc and flux vektor motor any help is appreciated

alexinter7

Anyone know about this? Plz share some knowledge guys tnx

mkiiina

iTrader: (71)

How were your motor temps? Does the esc smell burned? What was your gearings?

Also usually you only bump a thread once every 24 hrs. Not everyone is on the forums all the time.

alexinter7

Ok i didnt get temps but i do know the motor wasnt hot the esc was though. The gearing was 23 pinion 93 spur

About the bump part tnx i didnt know that im new here i do appreciate any help though

alexinter7

And the esc doesnt smell burnt

mkiiina

iTrader: (71)

what are you running (chassis, battery)? We need more information. Define hot? Could you touch it, if so how long could you have your finger on it?

When you pulled it off the track how was it acting? After you charged the batteries did you have the same problem?

Voltage spikes used to be a bigger problem when the batteries couldn't keep up.

Fast04STi

iTrader: (2)

As far as I know that ESC is a rebranded Castle Creations Sidewinder that is waterproofed. Waterproof ESCs tend to have heat issues to begin with. I think a root part of your problem is that you were braking and accelerating very hard on a sensorless motor and speed control. Under hard acceleration sensorless motors tend to cog and generate excessive heat, same thing goes for braking. Actually accelerating quickly after hard braking causes the most cogging.

alexinter7

Ok the motor i could have held it for minutes, the esc i picked up the car and my fingers got ahold of the esc and within 4 seconds it burned my fingers the chassis is an hpi sprint 2 flux the battery is an hpi battery with 3300mah i stopped running it because the car stopped and when i charged the battery again the motor would just twitch and the esc starts getting warm

alexinter7

So if instead of braking around the turns and let it "coast" around turns will that help heat stay at a minimum?

mkiiina

iTrader: (71)

I tend to disagree with that, all the sensorless cogging i have experienced has been a very slow, almost crawling speeds.

To the op, you are geared too low I think. Move up a few teeth on the motor side and down a few on the spur. You currently have the largest spur that is available for your kit. That should help with your esc temps.

alexinter7

Awesome i appreciate your help

Fast04STi

iTrader: (2)

Being heavy on the brakes usually results in slower lap times also. Braking generates heat just like accelerating. Try running a drag brake setup and don't stab the brakes as much.


That would lower the gear ratio even further. High motor temps are usually a sign of gearing a car too low, not the other way around. Every sensorless setup I have messed with gets very hot when I am on the track, not so much when I'm bashing it. I have always attributed this to motor timing on and off the throttle/brakes.

mkiiina

iTrader: (71)

I should have specified. His pinion needs to go up a few teeth and spur needs to drop a few. Currently he is a an 8.61. Moving gearing around some (lets say 26/84) will take him to 6.88. To the OP you might want to consult your manual. If you don't have it, its posted on the HPI racing website in pdf form.

I run mainly sensorless setups and the temps (when geared correctly) are comparable to my sensored setups. If you look at most good sensored esc's they start out in sensored mode to get started (smoother power delivery) and then switch to sensorless when speeds increase.

Some can also do turbo and boost which will advance timing and lead to more heat on the motor but also more speed.

Fast04STi

iTrader: (2)

Okay, I was a little confused because you said he needed to lower his gear ratio because it was too low. Althought, I must admit, I do not see why lowering the gear ratio would lower ESC temps. Generally speaking gearing a motor lower increases motor and ESC temps.

You are correct that a sensored speed control/motor runs in sensored mode only until the crossover point at which the hall effect sensors (what makes a motor "sensored") are no longer of use. They are mainly used when accelerating hard out of a turn after decelerating.