It's tough to give a generalized answer to this question. It varies bike to bike, for different tires, rider's weight, application and terrain.

If you inflate the tire to close to its max allowable, you will get the better battery range; however for electric bikes it is recommended to maintain pressure below average to damp shocks and vibrations transmitted to battery and motor. Generally speaking for a 1.95" thick tire 35-45psi, for a 32mm tire 45-55psi should be fine.