Overheating motor on Torment - brushed 3S LiPo

C

Chuckstasy

Active Member
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Hi all,

I’m new to RC and have been experiencing massive motor overheating issues. I’ve done a fair bit of reading but can’t seem to resolve this problem.

It is a 2wd 1:10 Torment that I got for Christmas so it’s one of the later generations. The only modifications are:
- 3S LiPo 5400mah
- Hackmoto 23T V2 brushed motor

Running stock brushed Dynamite wp ESC which is 3S compatible

Driving it fairly hard for less than 5 mins with the throttle limiter at 75% and the motor is way too hot to touch for even 1 second. Tested from cold with the stock 19T pinion (stock 87T spur), as well as 17T, 22T and 24T. All super hot after 5 mins on hilly pavement. ESC is warm but not hot. I was very surprised that the it was getting this hot at only 75% throttle (approx only 8.3v to the motor, which is supposedly rated to 11.1v). I haven’t dared to try 100% throttle until I get this overheating addressed.

Any advice would be greatly appreciated. I’m really not wanting to scrap the whole lot and spend a heap of money on brushless.

Gear mesh is perfect. Everything is moving freely, no resistance on the drivetrain. Stock tyres.
 
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Have you taken a temperature reading? Anything under 160 degrees farenheit is okay. You already checked all the normal things I would check first (binding in the drivetrain). Your esc is rated for 3s, but a 23t motor is a fairly slow motor for that much power. Try a smaller battery and see how that affects it.
 
Thanks for the quick response. From what I understand, higher voltage battery requires lower kv/more turns?

I’m really wanting to stick with the 3S to get more power. I did try a 13T Hackmoto motor but it overheated even more quickly (1-2mins 18T pinion). Using the stock 15T Dynamite at 75% throttle overheated but nowhere near as quickly (10 mins, 18T pinion)

Unfortunately no temp gun :(
I’m touching the end of the can, and can’t even hold my finger on for half a second.
 
Temp guns are cheap and necessary once you start hopping these things up. When changing pinion and motors and always with a brushed motor we check temp after 6 minute runs, sometimes having to let them cool down a bit. Temp guns are cheap insurance and can be found on ebay, Amazon, Tractor Supply, and many hardware stores.
 
I had doubts about my "finger on the motor" approach too!
I actually had no idea that temp guns were so affordable but I looked them up earlier this morning and one is already on its way. Will redo testing once it arrives.
 
Have you tried a bigger pinion than a 24t.
Running a bigger pinion will help cool a motor running 3s.
 
I don’t have anything above 24t, however I would imagine going that big (stock is 19t) would be too much strain on the motor?

My temp gun arrived and I was able to take the car out for a quick test today. Only fit in 5 minutes and got the following temperature readings:
- 40-50C (104-122 Fahrenheit) around the can, solder joints, commutator, and lower brush
- 95C (203 Fahrenheit) on the upper brush only
Is this one hot point something to be concerned about? I found it odd that only the upper brush got hot.
 
What are you running the car on. Grass tarmac. Also what is the discharge rate on your 3s. 20c 30c. And are you doing speed runs for the discharge duration.
 
The larger pinion gear with 3s was advised to me by my local hobby technician Because that's my next move. I haven't tried and tested this theory but he said this is what you must do to keep temps down
 
I was doing short speed runs on tarmac. Battery is 35c.

I did go up a pinion from stock, so from 19t to 20t. Will try a 21t and 22t when i get more time.
 
Chuckstasy said:
I don’t have anything above 24t, however I would imagine going that big (stock is 19t) would be too much strain on the motor?

My temp gun arrived and I was able to take the car out for a quick test today. Only fit in 5 minutes and got the following temperature readings:
- 40-50C (104-122 Fahrenheit) around the can, solder joints, commutator, and lower brush
- 95C (203 Fahrenheit) on the upper brush only
Is this one hot point something to be concerned about? I found it odd that only the upper brush got hot.
Click to expand...
Anything under 160 F is appropriate. They can take small doses up to 180, but after that it’s damaging the magnetism of the motor if it’s brushless. Brushed motors don’t want to be run over 160 f.
 
What I'm wondering is if the temperature of the top brush is the one to go off? Coz it seems like that is the only hot spot and the rest of the motor is fine?
 
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