Below is my main power back bone that is based on one of Bob Nucholl’s “Z” diagrams. When looking at this note that:
- The main alternator will be completely isolated if an overvoltage condition is detected. This is accomplished by having a Perhelion Design LOVP module control a solenoid which in turn controls both the field and B lead of the main alternator.
- There is a dedicated engine bus which powers only engine related devices. It can be powered via the main bus and/or directly from the main battery. The Schottkey diode that connects the main bus to the engine buss prevents power flow from the engine bus to the main bus. This preserves the battery power for the engine in the event of a main alternator / backup alternator failure.