motor and batteries stay cool, esc gets hot

[standard_63]

I just got a warrior 9920 and a Nemesis 6xl and am running 4s lipos in my Emaxx, and finally have cool motor and batteries but the esc is getting real hot after about 2 minutes. Since the motor and batteries are cool I don't think it's drawing too much current, what could be the problem? I have brakes turned down to 35% to keep load off esc. I'm running all UE parts and 40 series mulchers with 14/51 gearing. This motor is a torque monster so is supposed to handle bigger gears, but would gearing down help? I origionally tried a 16/51 but after 14/51 the motor was warmer...was told not to use a fan as that just puts thermal meltdown off longer as it masks the problem?
Thanks for any insight!

Also use Gmaxx 2nd gear conversion...

Would using ubec help it run much cooler? Do I have to cut the shrink away to get to the jumper?

[MetalMan]

The 6XL really is stressing your 9920. It can pull a lot of amps. Putting a fan(s) over the 9920 will keep it cooler, but there is nothing better than using a controller that can handle the amps. It wouldbe a good idea to use a UBEC just to keep the BEC chip from getting too hot. BTW, what batteries are you using?

[Batfish]

Originally posted by standard_63
was told not to use a fan as that just puts thermal meltdown off longer as it masks the problem?

This isn't meant to be rude to whomever told you this, but logically speaking it just sounds like a silly statement. Sounds like whomever it is wouldn't use an air conditioner on a hot day because it only masks the problem that it's still hot outside, and if the air conditioner wasn't there it would be hot INside, too :)

[Dafni]

I agree with Batfish!
Fans help to displace heat.

I would suggest a 120 amp controller.

[standard_63]

Alright, I'll try the ubec and maybe a fan. On my last controller when I was having thermaling problems I finally got a fan, and while it allowed me to run longer the controller fried shortly after! It was cool on the outside but burning on the inside...

The 6xl specs don't seem that much more radical then the 7xl, and many people seem to run the 9920/7xl combo no problem -- maybe I should just get a 7xl. It would be cheaper than another controller.

Dafni -- you finally solved your heat problems on the E-Revo? Was the solution just to add a fan?

[Batfish]

As far as heat dissipation, I'm sure someone here could give you an entire technical lecture on it, but I'm better at the simple approach.
Your 9920 is a good example to use in an explanation since it has a heat sink on it already. The purpose of the heat sink is to draw/conduct heat away from the component(s) that is heating up. This is why, generally, heat sinks have many fins; these fins provide more surface for the heat to be released through the sink. Logically speaking, if you can keep the heat sink cooler it will be able to gather more heat from the component(s) and help the component(s) to stay cooler as well. This is why air flow is essential, and why the heat sink isn't inside of the shrink wrap. Forced air flow (fan) enhances the effect by moving more air past the heat sink allowing it to dissipate more heat.

One actual argument to back up the "masking" concept can be made by approaching it a different way. If your setup is wrong, a fan won't fix it. For instance, if you're geared wrong and pulling too many amps, a fan won't increase the amp rating of your controller, but it may let it run a couple minutes longer before it thermals/fries.

Almost all of the advice for cooling on this forum comes with the premise that the setup you're using is appropriate for the vehicle.

[Dafni]

Once again, Amen to what Batfish said! I spare you with technical gibberish, this has been discussed here more than once.

Standard, I cured the fever of my Revo with a 7XL Wanderer :)
The 9L just runs a bit too hot for my taste. On the 7XL I can run pack after pack without ever exceeding 70°C on the motor. (14 or 16 cells)

Just for the record, I never had serious thermal problems on the ESC, just the motor.

[coolhandcountry]

The 6 xl is drawing to much amps. bigger amp esc or 7xl will fix this. But other people have said this to. Hope you get it fixed and ready to roll.

[standard_63]

I'm not throwing any more $$ at this thing, shelf queen it becomes...NOT!

I need help -- just ordered 16016. This better do it!!! I hope Mike can ship out today...I'm jonesin' to get this thing running!!

[standard_63]

So I just realized that when I programmed my 9920 I had the brake setting at 35 on my transmitter. I should have had it at 100. Would that cause the brakes to apply when I coast at all, making the controller heat up more than it should? I'm at work right now and can't test it, but I'm hoping that it will run cooler once I reprogram it. Think it will?

[Nick]

Can the fan just go in a spare reciever slot? Where is the wires fitted if not?