Charging Systems And Protection - Back To The Basics, Part II Photo Gallery
Next, you have a voltage regulator also inside the back of the alternator. The voltage regulator controls the amount of power that the alternator can produce. The regulator measures the battery voltage drop under 14.2 V and has the ability to add and take away resistance, causing more or less charge to the battery. It can do this by using a variable rheostat inside that controls the available ground output on the rotor. If the regulator supplies 100 percent ground then the alternator will be at full output. So if the charging system only needs 25 amps then the ground will be reduced via the rheostat in the regulator producing a lower voltage.