higer kv lower kv whats it all about

dumb question here be here it goes.i know you guys say that a lower kv motor and higher volt battery will make a motor and battery stay cooler, but say a i have a motor say 3000kv on a lower volt battery 14.8 at 15c ,will that
work.i am new to this brushless thing still trying to learn a few things. and i know you guys know your stuff,because i have been reading here for a while.
thanks.

[johnrobholmes]

With a lower KV motor, the battery and wires will be cooler because of the lower amp draw. You can use smaller cells or cells with less amp rating, but you must have higher voltage to compensate. The motor will not necessarily run cooler because it will have higher resistance along with the lower KV. Generally, efficiency of a motor does not change much with KV, although there are sweet spots with wind count because of wire fill. There are also sweet spots with motor design, as long PM motors (1:1 stator diameter to length) tend to have higher efficiency than shorter versions.

[lincpimp]

To add to JRH, motor choice is the most critical part of the equation. That is why it is a good idea to post the vehicle you plan to use, tire size, desired top speed, useage of the vehicle (bashing, racing, speed trials, etc), and any other info you can think of.

3000kv on 4s lipo is a decent setup for a 10th scale vehicle. If you plan to run a larger vehicle 2500kv or less is good for 4s lipo. Generally motor rpm should be somewhere between 35,000 to 40,000 rpm. If you plan to use a cheaper motor like a feigao in a heavy vehicle, keep the rpms to around 35k.