Adding A Battery Disconnect Switch
Dear RV Doctor:
My new motorhome did not come with a disconnect switch for the batteries. I want to install one, but I’m unsure of the proper way. Should it be on the negative or the positive side of the cables? Do I need to install fuses anywhere?
Cary De Mint, Corona, California
I’m a big fan of using battery disconnect switches (relays), so I encourage you to have one installed. When done correctly, the device can extend the life of the battery bank. And like almost all RV switches (with a couple exceptions), they interrupt the positive side of the DC circuit.
It’s best to mount it as close to the battery as possible and make sure the line from the battery to the relay is equipped with a high-amp breaker or fuse. Available devices run the gamut from a simple, mechanical knife-type manual switch to advanced designs that include remote panels, voltage monitors, etc.
I like the disconnect switch produced by Intellitec Products LLC (www.intellitec.com). The switch employs solenoids that use battery current only when connecting and disconnecting the batteries from the system. In other words, there is no drain on the battery bank after engaging the switch. This is accomplished by the use of a latching relay rather than a simple, heavy-duty switching relay. It uses battery power only briefly to engage and disengage the device. The nice thing about the Intellitec disconnect relay is that all fuse protection is integral to the relay, with two 5-amp fuses mounted on the relay. One fuse protects the LED indicator and a voltmeter (if you choose that option). The other fuse protects the remote switch, which mounts at any convenient location inside the RV.
Adding A Home Theater Sound System
Dear RV Doctor:
I have a 2003 motorhome, and I want to upgrade my stereo to a home theater system. How do I remove the inside wall panels to access the wiring?
Tom Worley
Divide, Colorado
I hate to be the bearer of bad news, but it’s highly improbable that you would be able to remove the paneling. There aren’t many wall surfaces inside the typical RV that do not have something attached or anchored to them. During construction, the walls are usually assembled on a flat table, bonded together, and then the cabinets, windows, cupboards, etc., are installed and secured to those interior surfaces. Any wiring inside the walls is installed during this fabrication stage or before the interior paneling is secured. Even with simple “stick” construction, once the wall paneling is in place, the manufacturer attaches everything else.
Shy of gutting the interior to get down to the bare-bones walls, most installers of aftermarket auxiliary equipment will simply find another way to route wiring and cables. It’s unlikely that you would be able to “fish” the conductors through the ceiling or the walls successfully. It’s probably a better idea to map out a location for the home theater system and route the wires and cables behind hidden cornices or behind or through existing cabinetry. There are some nice installations out there, so it is doable, but it may take a professional to complete a first-rate job. But I wouldn’t spend any time trying to remove the interior wall paneling.
Adding A Second Roof Air Conditioner
Dear RV Doctor:
We have a 2005 motorhome. It has 50-amp service and is prewired for a front air conditioner with a switch in the hall closet for the second air conditioner. We have ordered a unit and will install it ourselves. Where do the wires for the AC for it terminate? There is a 14-inch-by-14-inch vent opening in the roof with 12-volt-DC wires. Where would we locate the 120-volt-AC wires?
Leroy Bogue, Keiser, Oregon
Your motorhome appears to be prepared for a second air conditioner. But are you sure those wires located at the 14-inch roof vent are for 12-volt-DC electricity? Manufacturers typically install a junction box with a blank cover plate in the ceiling near the location where the second unit is to be installed. If you remove the blank cover plate, you should find the 120-volt-AC Romex wiring coiled up and capped with wire nuts. The other end of the wiring will terminate somewhere inside the panelboard distribution box, but the wiring should not be connected to a breaker yet. If your motorhome does not have a J-box in the ceiling, look for the Romex wiring somewhere inside the 14-inch opening. It’s possible that you may have to remove the inside garnish trim of the 14-inch roof vent that’s located there now. There should be a hole drilled through the surrounding support blocking with the end of the Romex visible. The wires should lead from the ceiling down to the breaker box. Once the air conditioner is installed, attach the black wire to the appropriate 20-amp circuit breaker, the white wire to the neutral buss bar, and the bare ground wire to the ground buss.
It’s an easy install when the manufacturer has prewired the motorhome; however, be very sure this is a job you want to attempt yourself. You might want to contact a certified RV service technician as a backup in the event you run into difficulties.