The “AUTO” button on the refrigerator selects AC power if it is available, otherwise the refrigerator runs on propane. This is a very convenient setting if you are planning to use propane whenever you do not have shore power. (Although some recommend you do not drive down the road with an open propane valve in case there is an accident.) This setting is also useful in camp when you do have shore power as it will fall back to propane if the campsite power fails.
The problem of the batteries being drained happens when the AUTO button is left on while boondocking. Then, whenever the inverter is turned on, the refrigerator will switch to AC, draining the battery when you wanted to use your propane. To get around this exposure you can modify the refrigerator power outlet to not be powered by the inverter. (Actually, since the refrigerator outlet is a dual outlet, you can leave one outlet on inverter power and the other without.
To make this modification you will need an additional 15 amp circuit breaker in your breaker panel. If your panel does not have a spare, you will need room in the panel to add one. You may be able to get room by replacing a single circuit breaker with a double circuit breaker. You will need about 20′ of 14/2 indoor Romex electrical wire and one 3/8″ Non-metalic (NM) Twin-screw cable clamp connector.
Gaining Access to Run the New Circuit
To do this you will need to run an extra 14/2 electrical line from your power compartment to the refrigerator outlet found behind the outside ventilation panel. Each coach model is different, but you should be able to run the new line by removing ceiling panels to expose access to openings where you can fish the line between the refrigerator outlet and your power compartment. The ceiling panels are removed by first pulling off the plastic seam between adjacent panels. Then remove any speaker or heat duct covers on the panel to be removed. Next, bow the panel down to release one edge from the groove along the wall. Then pull the panel out of the opposite wall’s groove.
Wiring the Receptacle
Before beginning to make electrical changes, be sure that shore power is disconnected, and both the generator and inverter are off. The 14/2 electrical line may be stiff enough to push through the ceiling over the refrigerator and in the other direction toward your power compartment and its access to the back of your circuit breaker panel. If not, you can use a metal electrical fish line. You should be able to use the existing cable clamp connector on the receptacle box for both the old and new lines. Connect the new line to power one of the dual outlets and leave the other outlet powered by the original line. Break off the two metal tabs on the side of the dual outlet receptacle to separate the two power sources. Screw the receptacle back in its box. Label the “INVERTER” outlet on the outlet cover.
Wiring the Circuit Breaker
Feed the new line in the power compartment into the circuit breaker box using a new hole in the box and a cable clamp connector. Connect the black wire of the new line to the output of the new 15 amp refrigerator circuit breaker. Connect the white wire to the neutral connection bar. Connect the bare wire to the ground bar. Visually inspect your work looking for proper connections and no missing insulation.
While you have the cover off of the circuit breaker box look for all of the wires that enter the box to be secured by electrical connectors or to have a plastic grommet protecting the wires from bare metal edges. Please note the red grommet in the picture to the right. I was alarmed to find those two wires exposed to abrasion on the bare metal opening before I added the grommet. Please add a grommet if you need one.
Power on the shore power and test your connections before closing up. Use an outlet tester in both outlets to verify the proper ground, neutral and hot wiring connections.
Label the new circuit breaker “Refrigerator” on the panel cover. Screw on the cover plates to the receptacle and the circuit breaker box.
Perhaps the hardest part to closing things back up, is getting the ceiling panels back into the groove around the walls. I found a wide bladed putty knife useful to help guide the panel edge into the groove. Once both wall edges are in place, you may replace the speaker and heat duct covers. Then you can replace the plastic seams.
Oh, and don’t forget to plug in the refrigerator and close the outside ventilation cover.
More recently we have had some trouble running our refrigerator on propane. It just doesn’t cool as well as on AC. Until we get that solved, we have plugged the refrigerator back into the inverter outlet and are careful to watch our battery voltage so we can recharge either with the generator or the alternator.