I have been installing solar in RVs since my first travel trailer in 1998 when I connected up with Arizona Wind & Sun in Flagstaff AZ. Since then, I have owned 3 towable trailers and 3 motor homes, all of which I setup with a solar charging system and 120 VAC inverter of some type. When I got my current travel trailer (GD 297RSTS), I opted not to go too crazy with solar capacity since we seldom camp without hookups. I mainly wanted a modest solar charging system to keep my batteries charged when in storage, and provide modest power for 3-4 day boondocking trips once or twice a year. I also wanted an inverter that would power any of the 120 VAC appliances, including the microwave (but not AC, water heater, or fireplace). What I ended up with is the system shown on this page:
For those familiar with electrical wiring, you can review the DC/AC Power Wiring here. To review the complete wiring diagram for my RV, go to the Mods - Wiring and Parts page and then select Mods-Wiring from the vertical menu.
What may be of interest is the switching scheme used for the inverter. With some advice from Arizona Wind & Sun, what I did was to re-arrange some of the 120 VAC loads so that all of the loads that I wanted to run from the inverter were on the L1 leg of the 120 VAC circuit breaker panel. All of the remaining loads (with the exception of AC 1) were connected to the L2 leg. Next I used a 50 amp automatic transfer relay to switch the L1 bus between the inverter output and external (campgound or generator) power. The L2 bus is not powered when on inverter power. This scheme powers most every 120 VAC outlet, including GFCI outlets, from the inverter,without the need for an additional inverter sub-panel. In actual use, this has worked perfectly. Proper selection of the 50 amp transfer switch was key to making this scheme work well. The WFCO T-57 switch (installation picture shown above) has features which support this use: (1) The normally closed relay contacts operate as a pass-thru path for inverter power without the need to energize the relay, and (2) very quiet (as in silent) DC relay coils when energized.
For alternate power when boon docking, I have a Honda EU3000i Handi generator that will power one AC unit with enough additional power to run the battery charger or refrigerator.