Choose the spot on your RV to mount the generator. If the RV was built to add a generator to it, the place to mount one should be described in the vehicle's manual. If not, the rear bumper or trailer tongue work well.
Mount the generator securely onto the vehicle. Manufacturers such as Cummins Onan build RV-style generators and the mounting kits for them that include brackets, wiring and exhaust. You can use these kits for a custom mount, but make sure your mounting bracket can handle the load of the generator. Reinforce the mount if needed.
Connect the fuel supply to the generator. If the vehicle doesn't have a supply option (class A and C motorhomes share the vehicle fuel while toy haulers have an extra tank), connect the generator to the on-board propane tanks or retrofit a gas tank. Choose the largest gas tank you can fit and make sure you have a good fuel pump.
Deaden the generator's sound as best you can. A built-in RV mount often has a steel enclosure that won't muffle the noise much inside the vehicle. Line the enclosure with sound deadening material such as dampening mats. Construct a similar enclosure for a custom mount.
Make sure the generator has proper ventilation and exhaust routing. Mount a PVC pipe to the RV's siding that travels above the roof. Clamp it to the exhaust port with a flexible hose. Make sure the enclosure's access door has a good size fresh air opening and the hot air is exhausted out the bottom.
Wire a transfer switch to the generator's AC output and the RV's shore power supply. This ensures you can supply the generator power to the RV without using the shore power.
Connect a battery that can adequately start up the generator; don't use the vehicle battery. A lawnmower battery should work for most models. A diesel generator or one using more than 5 kilowatts needs something larger. Check the generator manual for the right size.
