Reply from tech support

[Thomas Porfert]

That setup is geared for ~55-60 MPH, the amp draw will easily exceed the capability of those batteries. We recommend as an absolute, bare bones minimum a 5000mAh with at least a 20C continuous discharge; which is good for 100 amps based on the C rating, the minimum we recommend for most setups. For a hot setup like this, you would want a 25 or 30C continuous. We have to account for manufacturing tolerances, battery wear and sometimes just blatantly false C ratings. We recommend removing ~20% from a batteries ratings and still shooting for 100 amps; so a 5000mAh at 25C would yield 125 amps, and 100 amps removing ~20% would be a much safer bet. There's no such thing as too high of a discharge, but there certainly is such thing as too low. You cannot run NiCd batteries with any of our systems, and NiMH's are only good for conservative setups. And they must be the highest quality NiMH cells and be assembled correctly (IE battery bars).

If this were setup to go 35-40 MPH, you might just get away with those batteries; but even then, there is some potential risk involved with that low of a continuous discharge. If you were to go to a 4s setup, or preferably switch to the 1512/1.5Y (1800kv), I would feel a lot more comfortable with that setup; but I still urge extreme caution using those batteries with a Monster setup, they really aren't powerful enough for these types of vehicles. A battery rated for 79 amps, and 63 amps removing ~20%, is a cause for concern; and if I understand correctly, this has happened 3 times before? Multiple failures on the same setup generally indicates a problem with the setup; or some of the worst luck ever, and in that case, go buy a lottery ticket and remember who told you to go get one when you win. :)

As BrianG mentioned, you can "band-aid" slightly inadequate batteries with extra caps, but it doesn't fix the underlying problem. If you were to gear a bit more conservative (drop the pinion, increase the spur) and add the caps, you have a much higher chance of success.

Thomas Porfert
Castle Tech Support

yup, too low of mah. i run 5000mah at 35c in a 11lb truck geared for 40.

but sounds like CC is going to do their awesome thing and replace it for him anyways.