IH: Electrical System

Circuit Breakers

The circuit breakers have copper and silver colored terminals. The copper is the input side. 1) The only exception is that the wire from the regulator attaches to the output side, then current passes thru the circuit breaker in reverse direction to charge the battery. Or you can run the output wire from the reg directly to batt+.


A diode is a one way electronic check valve that only allows current to flow in one direction. 2) On Sportsters, the diode is installed in the “Gen” light circuit to theoretically tell you if the generator/regulator is working correctly. If all is working the way it should be, with the bike running and everything working correctly, the generator/regulator will be producing a higher voltage than the battery (i.e. it's charging the battery). The voltages at each end of the diode will be such that the diode allows no electricity to flow through the circuit, and the “Gen” light stays off.

If your generator/regulator takes a big dump and stops producing the correct voltage, the battery voltage will be higher than the voltage being produced by the generator/regulator. The voltages at each end of the diode will then be “reversed” from normal, and that will cause the diode to allow current flow. The “Gen” light will light up, telling you that something is wrong. That's why the “Gen” light lights up when you first turn the key on, as the battery voltage is higher than the voltage being produced by the generator/regulator, since they aren't producing any voltage with the engine not running.

Other Related Topics

In the EVO section: Battery Cables - The Place to Start
——- Also There: Battery Charge Level - Battery Voltage Readings - Testing For Proper Grounds

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