Hot E-Maxx motors
 

Hi, just got my new 3905 E-Maxx running. The motors are running hot.(180-190) Speed control (EVX2 w/fan) 15-20 above ambient. Batteries (Turnigy 2s2p LiFePo4, 4.5 amp/hr, 6.6 volts) also 15-20 above ambient.Geared 22/68. Wheels/tires virtually same size and weight as stock. The motors are Astroflight #615 cobalt brushed.(7 pole skewed arm,10T of 21guage wire .069 ohm, oversize 7/16" communtator w/silver graphite brushes, machined aluminum endpieces and steel can w/10 cobalt magnets,BB's,KV 1488.) The truck weighs 10 lbs 5oz. Any ideas? Motors are about the size of a 550 brushed and weigh 7.5 oz. Thanks, Don

Brushed motors > suck balls.

Lovely as the description on the cobolt motors is, I doubt they are anything all that amazing or designed to be long lasting without much maintainance. Your gearing is wayy top high though- you should be using nothing higher than stock (18/68) with the evx2 as it wont stand upto much abuse as such- same deal too with the stock titans, so I;d say your motors are running hot because they are overgeared, regardless of the slightly lower speeds that the Life packs offer ( 13.2v nominal, 14.8v freshly charged ).

I'd say gear back down and see how things respond- should hopefully run cooler provided no damage has been done to the motors with the high temps..

OK, looks like gearing down is the way to go. These particular motors were bought a while ago-not cheap-$135 each. At the time they were popular(and King of the hill) brushless were pretty much unavailable. In their FAI form they held a # of records for RC airplanes and were used for drag racing and pulling quite successfully. I had them on hand when I bought my E-Maxx a month ago and decided to use them. Don

Wow, :surprised::surprised::surprised:

$135 each motor? Hmm. How long ago are we talking?

I bought these probably 4 yrs. ago. They are available @ New Creations-RC on sale $110. These are some of the best compitition brushed motors. They will run @ 80% efficiency. I know-they aren't brushless! Before brushless these were the thing to have. Don