When properly restored, the original Ford generator can meet all the electrical needs of a stock model A. However, by inherent 3-brush generator design, voltage can easily rise above 8 volts. Anything above 7.2 volts starts to boil out battery electrolyte. This is where Mike Hill's Electronic Voltage Regulator (EVR) really shines. It limits generator voltage to a maximum of 7.2 volts as well as controlling current output. It mounts internally, replacing the 3rd brush assembly - making it a 2-brush generator. The EVR can go a long way towards extending battery life.