Kraton Motor Temp - Am I Missing Something?

[RCBro80]

So, I've had my 6S Kraton since October, and have never found motor temps to be more than warm (running the stock pinion and tires), likely because of the cold temps here in Canada. As the temps have been rising a little I've been noticing motor temps are quite hot when running on 6S (I don't have an IR temp gun, but I will say 160F ish). From what I read, this is about the safe limit for brushless motors. Is this true?

If so, why is it that I see guys gear up their rigs without a motor heat sink/fan even in seemingly warmer climates. I also find it strange that the 4S and 8S models ship with a heatsink, but not the 6S.

Obviously it can't hurt to add one, but is it required? What kind of temps do you guys see and what is your comfort level?

Thanks!

 

[jkflow]

1st get an IR temp gun, they are cheap and you don't have to guess. You will be unpleasantly surprised is my guess.
Comfortable levels ~ up to 170, safe up to ~ 180-190, anything beyond is questionable and almost certain will do damage even if not immediate. Mainly the glue holding the kevlar wrap will break down and that's how it starts.

Temps will go up quickly if your bearings go bad or something starts binding.

I'm in FL and run with fans but the drawback on those is that they don't last long when jumping. Heatsink by itself is useless.
I typically disable or remove pending the type of bashing. I mostly run on grass which adds resistance and heat and they definitely help. I'd say it's required here in FL.

 

[jondilly1974]

180F tops. If yours stays under that without a heatsink or fan, no need for it. If it creeps up past that, time to add one.

 

[olds97_lss]

With the gearing (15T pinion) I had and tires I run (strapped trencher 3.8's), mine would get to 165F or so on 4S. I installed a single fan heat sink and it kept the motor in check. I could run 16T at the skate park, but I spend a lot of time in grass at parks as well, so I had to drop to a 15T or the esc would overheat. Seemed fine for the first year or so, then I switched to 6S and then had the esc thermaling on me at about 10 minutes with a 14T unless I geared down to a 13T pinion. Then I was able to run 16-18 minutes until LVC without things shutting down.

I replaced my esc with a max6 (more amps) in hopes I could run a 14T pinion with 6S. During my first max6 bash session, I cooked my first motor due to the fan dying and I didn't know it. Motor was 259F when I checked it. It still works, but has very little resistance to it when I spin the output shaft by hand. I'm surprised the kevlar/epoxy inside didn't let go, but it seems fine, just lost the magnet strength.

When installing the new motor, I replaced my single fan heat sink with a dual and mounted alloy framed fans to it as well. Alloy framed fans are less likely to break and also add more heat sink. I figure if one fan dies, I still have another.

I'm in Northern IL. Temps/humidity are all over the place here. I don't run the outcast much when it's cold as the temptation to air it out is too great, so it stays home unless it's 50F or more. Most of my thermal issues were when it was 75F-85F outside. When it's more than 85F... I'm likely to stay inside anyway.

I'll see how it does during the next bash with the 14T/max6 and new motor cooler in it.

 

[jkflow]

The max6 combo motors i.e. 4985 are a lot more heat resistant from what I can tell. Must be using different type epoxy/glue.

 

[olds97_lss]

The max6 combo motors i.e. 4985 are a lot more heat resistant from what I can tell. Must be using different type epoxy/glue.

I was/am still running the blx2050kv motor. Was thinking of upgrading to something a bit more capable, but covid, furlough, salary cuts make it hard to drop another $100+ at the moment. If it doesn't do ok, then I'll gear it back down to a 13T and live with it for a while.