Modern motorcycles have electrical charging circuitry for the battery, of which the regulator rectifier is a standard part. The name of the part is actually indicative of its function as it rectifies and regulates voltage. AC voltage is generated in the alternator's stator coil. For the most part, motorcycles are on a three-phase system for efficiency purposes, where three wires connect the stator and regulator rectifier. Even so, there are some single-phase systems available as these are cheaper to manufacture, but the system uses two wires instead of three. The regulator rectifier first converts the AC power into a surge of DC power, then normalizes the DC power, ensuring that the power does not exceed approximately 14.5 volts. The DC voltage is then routed to the battery.