first brushless, few Q's

[stanmondz]

i got a dynamite mini tazer esc and a E flight park 370 5400KV motor for my 18T, it runs great,plenty fast. i got it used off here. i lloked up the manauls for both and the esc can handle a 3s lipo, but e flight says the motor is only good for a 2S. my LHS says the motor can do a 3S lipo and showed me in the directions in the box of a new motor that it can run the 3S.

whats the worst that could happen if it can;t handle the 3s?

[Cotharyus]

It will spin so fast that it comes apart.

[GSMnow]

A 5400KV 370 motor should not be in any danger of over revving at just 3S. Most well made 380sized motors rev to 100,000 without failure, so this should be fine. Castle rates the much larger rotor CM36 (540 sized) motors to 70,000 and they run the 5700 on 3S with warranty coverage.

5400 x 11 = 59,400 rpm. That should be no problem at all. If it fails at that speed, it had something seriously wrong to begin with.

With that said, be sure to gear it correcly and monitor the temperature before doing long bash fests with it. On 3S a 1/18 car (or truck) should be able to be geared for 40 to 50 mph depending on surface and driving style with little worry of hurting it. And some have geared over 60 mph, but then you must closely watch temps and drive it knowing you are pushing limits. Always start geared slow and move up. I keep seeing people say undergearing is bad, that is a total hoax. The only way a motor will be hurt while under geared is if the voltage x KV RPM is beyond the motors limits and that is a bad setup to begin with and will never be reliable in use. I have run my Mamba Max 5700 flat out no load on 2S and it runs cool. 3S is close to rev limit on it, so I won't be free spinning it up there, but even geared very slow in a car I would not be worried. Taller gear will pull more current and make it hotter. No mystery about it.

[rccardude04]

The E-Flite 5400 is actually not rated for 3s lipo. I think it just has to do with the fact that it will be VERY hard to prop on an airplane, which is what the motor was intended for.

You should be fine. Just watch the temperature.

-Eric

[stanmondz]

what dose the "C" rating mean? i see it on all the lipo's the thunder power pack im looking at is a 20C 3cell 2100 might be 2200 i dont remember

[Cotharyus]

When you're working with batteries "C" is the capacity of the battery. When you have a 2100 battery rated for 20C output it means it will output 42 amps constant. No disrespect intended, but if you plan to use LiPo batteries, you owe it to yourself and those around you to research batteries until you can answer these questions backwards and forwards yourself, or else you stand a really good chance of hurting your self or someone else. At the very least, LiPo's are expensive, and you need to be able to protect your investment.

[stanmondz]

thats what im doing, i know lipo's can be dangeous. im also looking at the lipo sack for charging it