[SteveZ]

Don't confuse voltage with power. As an example, that hairdrier or electric razor in your bathroom runs on 110 volts in the US and Canada, but the same unit (with a flip of a switch) often can run in Europe and Asia on 220 volts there. It uses the same amount of "power" regardless of the voltage and doesn't run any faster, better or stronger.

I copied this from an engineer's description comparing electrical terms: Voltage pushes electric charges through wires, and also through an electrical resistance, which heats up the resistive object. The flow of the charges is measured in amperes, the flow of electrical energy into the resistive object and the heat output is measured in watts, and the resistance is measured in ohms. Amperes and Watts are two different kinds of flow, yet both happen in circuits.

Bottom line: comparing voltages is sort of like comparing gasolines - is premium gas "better" than regular gas? And the answer is - depends on what the engine of the car was designed to run on. So, if sales folk try to say 48-volts are "better" than 36-volts, they are counting on the fact that you may have no idea on how electicity does what it does....