The engine alternator is the primary source to charge the chassis battery.  A chassis battery requires alternator charge because unlike house batteries that are designed to deep cycle, a chassis battery is not of the same construction.  A chassis battery is rated in Cold Cranking Amps.

Certain electronic transmissions and engines are voltage sensitive and failure of the alternator can affect these other systems.

Keep an eye on the alternator while driving down the road by monitoring dash gauges.  Many motor homes are equipped with Alt Charge or Alt Fail icons.  On gauge or voltage indicator systems, a drop below 12-Volts while the engine is running is strong indication of a problem with the alternator.

While driving, avoid running large electrical loads in the motor home that can put too much strain on the alternator.  If you want to operate the microwave for more than a few minutes while driving down the road, put less of a load on the alternator by running the generator to supply power.  

To assure the alternator is working as designed, inspect the alternator at least four times per year.  Before visually examining the alternator, remove keys from the ignition to prevent accidental engine start up.

Coaches equipped with a side radiator system can access the alternator through the rear door engine compartment.  Rear radiator system motor homes will require that you crawl under the chassis and use a droplight to inspect the alternator, or there may be an access hatch in the floor of the bedroom.

1. Visually examine the alternator belt or serpentine belt.  Look for cracks or damage, such as tears or fraying.  Rock chips can get caught up in the belt and cause destruction.
2. Inspect the alternator and remove any dirt or oil that has built up around the outside case.  Be sure there is good airflow around the alternator that will allow the system to properly cool.
3. Physically move the cables to assure all connections are tight.  Tighten loose cables and check for signs of burnt wires.  Confirm spring belt tension is in proper working order.
4. Lastly, start the engine and go back to listen to the alternator for sounds of squealing or growling that can indicate a problem.

If it becomes necessary to remove the alternator to perform repairs, be sure to first remove the cables from the chassis batteries.  This will prevent injury from contact with power in the cable.