NewMar Essex 2014, Manual

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2014 Newmar Essex Diesel Pusher 92
12 VOLT DC SYSTEM
General Information
There are two separate 12 volt DC electrical systems on your Essex; one for the “chassis” portion,
and the other for the “house” portion.
The “chassis” electrical system uses DC voltage to operate chassis related electrical accessories
and lights, such as the headlamps, dash instrumentation, engine starting and management
circuitry, and so on. This system includes a set of chassis batteries, and is charged in transit by the
alternator. The chassis batteries have a disconnect switch located in the rear engine compartment.
The “house” electrical system uses DC voltage to operate all the house related DC lights and
accessories, such as the interior lighting, ceiling vents and fans, slide outs, the water pump, and so
on. The house electrical system also supplies the power (through the house batteries) for the
inverter to operate. When 110 AC current is present, the inverter has a charge circuit that engages
to charge the house batteries.
Though separate in operation, the two DC electrical systems are tied together through a battery
isolator circuit. This circuitry is designed to keep the systems separated under most operating
circumstances, but still allows them to be tied together under certain conditions. This is
accomplished through a component called the Bi-Directional Isolator Relay Delay (BIRD). This
component allows the two separate battery systems to be tied together for charging purposes or
for “boosting” purposes if one set of batteries is low.
In transit, the alternator on the engine is the power source for charging batteries. The function of
the “BIRD” allows the chassis batteries to be recharged off of the power coming from the
alternator. Once the chassis batteries have been recharged (approximately 13.3 VDC), the
“BIRD” will turn on circuitry that will then allow the house batteries to be charged in transit by
the alternator. This allows both sets of batteries to charge while the coach is in transit.
When the RV is parked (with the engine off), and is connected to 110 VAC power (either
generator or shore power), the “charge circuitry” in the inverter will engage, and will charge the
house batteries. Once the house batteries have reached full charge (approximately 13.3 VDC), the
“BIRD” will again engage circuitry that connects the two sets of batteries together, allowing the
charge circuit in the inverter to charge the chassis batteries as well. This “Bi-Directional”
operation works to keep both sets of batteries charged to capacity, regardless of whether it is in
transit, or parked with incoming AC current.
12 Volt DC Circuit Protection
House Circuits
The “house” fuse panel is located in a cabinet in the bathroom. This panel contains fuses for most
of the Newmar installed 12 volt DC accessories, including interior lighting, vents and fans, and so
on. The fuse panel uses conventional “spade” type automotive DC fuses. Fuse amperage is
labeled on the end of the fuse for easy viewing and replacement.