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-   -   Mamba Max Gets Hot (https://www.rctech.net/forum/radio-electronics/427388-mamba-max-gets-hot.html)

espesso17 08-20-2010 11:41 AM

Mamba Max Gets Hot
 
Hey,

I recently purchased a mamba max off ebay. I am now running it in my xxx bk2 with a 3300 matched pack.

Battery: 3300 matched
Motor: Mamba 7700 kv
Pinion: 21
Spur: 78
Motor Timing: Set Low

I basically have everything on the ESC set to factory default. While my motor does not get too hot, my esc gets hot enough so that I can only keep my hand on it for a few seconds before it gets uncomfortable.

Is the esc suppose to run this hot?

Duster_360 08-20-2010 02:07 PM

Shouldn't run that hot. The hot esc with a motor and batts that are not hot is the classic indication of being undergeared. Its a gearing issue, you need to go up a a few teeth on the pinion.

stu22 08-20-2010 04:24 PM

Get a temp gun and find out how hot the thing really is. I usually gear to 150F for the motor.

Lazer Guy 08-21-2010 07:01 AM

I might be wrong but this is how I see it.

Your ESC will get hot if your pinion is to big.
Your motor can get hot if your pinion is to big or to small.

If you put a smaller pinion on the load on the ESC goes down (less amps) ???

The sweet spot is when your ESC and motor are the same temperature ???

Duster_360 08-21-2010 07:22 AM

Quote from RC Monster -

"Although not always true, a rule of thumb is:
Hot motor, cool controller, cool batteries = undergeared
Cool motor, hot controller, hot batteries = overgeared
Warm motor, warm controller, warm batteries = happy components"


There are a few exceptions recognized, one being way overgeared where all 3 components run hot....

burnineyes 08-21-2010 05:02 PM

Thats a pretty good rule of thumb, but 21/78 in an off road car with a 7700Kv motor seems extremely high to me. I know my T4 has taller tires, and possibly a different transmission ratio, but when I tried a 7700Kv in it I had to use 12/87 to keep everything cool. It was still way too fast for an offroad track with that gearing. I do agree about getting a temp gun so you know exactly what temps youa re hitting. A few buddies and I always disagree how hot an ESC/motor feels before actually measuring it. But typically around 150F will burn my finger after a few seconds, higher than that and I can only touch it for one second or less.

espesso17 08-22-2010 03:26 PM

Thanks for all your replies. I felt that I definitely over geared my motor. Simply because I dont have another pinion on me.
Ill order one soon enough. Thanks for your help!


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