Ignition Coil & Charging Coil
Ignition Coil On every motorcycle along with a battery, which is used for providing power for starting the bike and for buffering an amount of electric energy.
The battery itself is charged by a generator (Magneto Assembly) driven by the engine. As long as the engine is running there will be a current flowing through the battery. The no-load voltage of a fully charged battery is about 13 Vdc. For charging it the charging-system should provide a voltage of about 14.4 Vdc. Also, this should be a constant voltage at all engine speeds.
The generator itself is located in or on the engine, and on most bikes, there is a separate regulator-rectifier unit. The reason for this is that almost all motorcycles are equipped with a three-phase AC generator. While the electrical system on the bike is a DC (Direct Current) system. The rectifier part inside the regulator-rectifier takes care of converting the AC-current to the DC-current the battery needs. The three-phase AC generator is used so often because it is much more efficient and reliable than a DC-generator. It can produce power for charging the battery even with the engine idling. The regulator part of the regulator-rectifier is used to regulate the output-voltage (to the battery) to the 14.4 Vdc that is needed.