How to Install a Power Converter in an RVby John Cagney Nash
Recreational vehicles (RVs) are designed to be entirely functional without a 120-volt alternating current (AC) shore or generator connection. Usually the only RV accessories that will not run from a 12-volt direct current (DC) source are air conditioners and TVs. For 12-volt source to function properly, the coach battery must be kept recharged. This is achieved by a battery isolator when the engine is running, and by a power converter when the RV is plugged in to shore power. Installing a power converter to the existing 12-volt "house" circuitry of an RV is an easy and rewarding project.
Confirm that shore power to the RV has been disconnected. Do not rely on throwing switches or removing circuit breakers; remove the umbilical cord from its outlet. If you have a generator, verify it is switched off.
Use a wrench to disconnect the coach battery's ground cable.
Fix the power converter firmly in place at a location where the heat it produces will be readily dissipated. Some units have an inbuilt cooling fan, and the location must allow for its unobstructed function. Most units have integral brackets or flared panels protruding from the sides with holes in them for attachment. Use screws appropriate to the substrate where the power converter will be attached.
Consult the manufacturer's literature concerning electrical connection and follow those instructions. A typical power converter will have a terminal for a 110-volt hot wire from the shore power source, usually black or blue; a terminal for a 110-volt negative wire from the shore power source, usually white; a terminal for a 12-volt hot wire to the coach battery, usually red or black, and a terminal for a 12-volt negative wire to ground, also usually white.
Restore the negative connection to the coach battery.
Plug in the RV's umbilical cord to its shore power source.
Use a voltage meter to test the power converter's output across the DC hot and ground wire terminals. The power converter should produce a smooth current supply of just under 14 volts.
- Do not confuse an RV power converter with a power inverter. The Institute of Electrical and Electronics Engineers (IEEE) defines an inverter as "A machine, device, or system that changes direct-current power to alternating-current power." An RV power converter does exactly the opposite, changing alternating current to direct current.
- If you are installing a new converter, it will probably be designed to operate with a full-time connection to the coach battery. For such units the battery serves both as a filter to absorb spikes in voltage and as a voltage boaster at times of peak demand. If your existing installation incorporates an in-line cut-off switch, it should be bypassed.
- The power converter is intended to replenish a 12-volt battery when it is in use. It is not intended to be used as a battery charger --- to provide a full charge to a flat battery. To use it as such will reduce the life of both the battery and the power converter.