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Thus, with later revision boards and with ignition off, the auxiliary start/charging
relay will drop out sooner (12.6VDC) to retain a greater amount of charge in the
chassis battery. It is normal for the charging relay to remain pulled in after the
engine is turned off. Coil current is approximately 1/2A for both models. The
diesel model has a heavier, intermittent duty coil. To enable the coil to be
continuously energized, full voltage is applied for 1/2 second and then the coil is
pulsed at approximately 50% duty cycle. Thus, a voltmeter will read about 6VDC
when the diesel relay is operating normally in closed position.
Gasoline and diesel models of Rev B and alter sense voltage from both the
ignition terminal and coach battery disconnect terminal. This allows the chassis
battery to be charged from the converter when on shore power. Necessary
conditions are : coach battery disconnect engaged, shore power on, converter
operating, and coach battery charged above 13.2VDC. When these conditions
are met the auxiliary charging relay will pull in and both batteries will be charged
in parallel.
