T maxx brushless conversion over heating

[big specht]

I’ve converted a 3.3 Tmaxx to brushless and I’m having a over heating issue in about 5 min or less of running it around. I’m running 21/58 gearing with a 120amp esc and a 3900 kv motor. I’ve ran it with a 2s & 3s battery. With same results. What do I need to do to keep it from over heating ? Gear it down some more?

 

[Greatscott]

What size of motor?

 

[big specht]

3900kv ?

 

[lonleycreeper]

He's asking what size can...

1/8th scale motor is recomended, and 20/60 gearing to start.

If you have a standard size 540 2 pole 3900 kv motor its not going to have the torque you need to keep the heat down.

 

[big specht]

It’s a 36mm can 4 pole 12 slot. I went 1/10th size motor over the 1/8th motor cause every thing I read they said it was going to be to much power

 

[Greatscott]

It’s a 36mm can 4 pole 12 slot. I went 1/10th size motor over the 1/8th motor cause every thing I read they said it was going to be to much power

"They" screwed you...

A 1/10 motor just cannot handle the weight of that rig, and that goes double for 3900kv motor. Even a lower turned 1/10, like a 1800kv, would likely not hold up well. A lower turned 1/8-scale ESC/motor, 2400kv (ish), is really the only thing that will push a heavy rig like that and not fry. I don't believe it will be "too much power", but if it is, you can always dial it back by gearing down, which will help the motor stay cooler.

Of course, this is assuming that you want this Maxx to go fast. I have a 540-sized motor in my E-Maxx, but it is geared to crawl, and the 45T motor does just fine, but she ain't breaking any speed records.

 

[big specht]

This was just a conversion for a buddy’s kids to play with. ? So basically I need a bigger motor, it seems to have plenty of power. So you guys don’t think changing the gearing will make that big of a difference with the set up I have already ?

 

[Greatscott]

It all depends on what you, or they, want out of it. If you want an RC to just putz around with, that has little speed, then go with a really small pinion, and a giant pinion. You might still have heat issues though. If you want the truck to have a bit more speed and performance, then look at putting a 1/8 scale system in it.

 

[big specht]

Ok I will try and a bigger spur gear first. The esc don’t care what size motor is on it as long as it has the amp’s to handle it right? I might just get a bigger motor this is my first time messing with brushless motors.

 

[big specht]

Well it was the motor not the gearing. I ordered the wrong size motor. I replaced it with a 550 size brushless motor and did gear it down 2 teeth anyways. And played with the programming of the esc and test ran it with a 2s battery in the grass going up and down hills wide open for a while and checked motor temp and it was fine, it wasn’t really much more then warm. So I will chock that up as a lesson Thanks for the info "thumbsup"