EyeintheSky57

Hi all,

My dad has a Losi XXX-SCT. Installed is a Duratrax ELEMENT combo with a 3900kv brushless motor and ESC (Box says "up to 100A")

He is using 2S 60C batteries.

He has stock gearing with 16T pinion and 88T spur.

So, One lap around the track and the truck dies on Thermal. ESC is hot as hell but battery and motor are fine and cool.

Any ideas as to whats wrong? Could a gearing change help?

Thanks.

AndrewTom

iTrader: (3)

the sidewinder esc is notorious for running hot. i ran a velenion in my xxx-sct with 20/86 gearing. i would try an 18 for now and be careful, use an IR temp gun on the motor, esc and pack.

EyeintheSky57

This isn't just running hot. The truck ESC is turning off on THERMAL protection. An 18T pinion would bring ESC temps down?

RatsacK

iTrader: (21)

Quoted from the interwebz. Seems you're undergeared. Put a bigger pinion on and test how it goes. Try an 18t first, if temps get better but are still not "good", try a 20t.

Grasschopper

iTrader: (54)

That HAS to be a defective ESC in my opinion. I have the same system in my XXX-T CR and the motor gets hot but the ESC has never gotten hot or shutdown thermally even after running for 15+ min. Motor hot? Yes. Battery and ESC? No.

I would contact Castle and see what they say.

AndrewTom

iTrader: (3)

i would spend 6 bucks on a pinion before i even consider contacting castle, I have had a BAD experience with their customer service.

Spawne32

Realistically anything that doesnt have a fan on it is going to get hot in an off road situation, and outside temps being the 90s dont really help either, but thermal shut down on such a low gearing to the point where the motor doesnt even get hot, that doesnt seem right.

Grasschopper

iTrader: (54)

Did you guys read his post? Your saying that he is SO over geared that the ESC heated to thermal shutdown level in less than 60 seconds. I don't buy that. Either there is a SERIOUS bind in his drivetrain or there is an issue with the ESC.

I have the same system running the same gearing bashing it in my back yard and the ESC never gets too hot...motor yes, ESC no.

Sinjitsu

That 60c lipo is kicking out 336 amps. I would guess that is the issue. Try a 20 or 25c lipo.