[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.