RV Solar Concept

[Browneye]

You probably have the same single cylinder onan 4kw I have. It's a great little poweplant. Quiet, sips fuel, they run forever.
Consumes about a half a gallon an hour, they run a thousand hours before any major service. I have seen them with a couple of thousand hours on them.

Ours is 17 years old, has right about 300 hours on it. If we need air conditioning it runs. Otherwise we plug in to shorepower. Or do without.

RC air units are energy hogs, and they're not very efficient. I think mine pulls about 25A on full load, but will coast at about half that. And it's only good for dropping the temperature about 25 degrees. If it's 110 out we can get to maybe 85. Trying to do that with battery will be an effort in futility. And they run constantly in any high temps just to try to keep up. On when the sun warms up and stays on till the sun goes down and you can open the windows and doors. A couple of hours just doesn't cut it if it's over a hundred degrees. We don't generally turn on AC till it's over 85-90. Thinking you can keep your RV at 75 when it's over a hundred out is rather hopeful thinking.

People running AC on battery are installing small window-air house units, or a small-btu mini split. Some of those are really low consumption - less than half of a RV air unit.

 

[Bobert]

30A system. Our RV is being stored at the dealership till spring (having them hold it, allows us to have the full warranty once we drive it off the lot), so I still need to size everything, but I hope this design fits or I will have to downsize accordingly.

I did something similar on our travel trailer. I used a 48v 3500w all in one inverter and installed it as if it was a solar generator. I left the entire 110v and 12v rv system untouched except for wiring the shore power through the all in one first. I use a portable generator if I need to subsidize the solar but if I had one onboard I would wire it through the all in one as well. Their are some efficiency losses from converting DC to AC and then back to DC but the redundancy of the system allows me to bypass all my solar equipment for repairs, upgrades or maintenance and still have a the original system operating from generator or shore power or battery as originally designed. Also in a worse case scenario where the inverters batteries are depleted I still have the original 12v system fully charged and able to operate my essential devices (furnace, water pump, lights, slides, ect)

 

[Browneye]

I did something similar on our travel trailer. I used a 48v 3500w all in one inverter and installed it as if it was a solar generator. I left the entire 110v and 12v rv system untouched except for wiring the shore power through the all in one first. I use a portable generator if I need to subsidize the solar but if I had one onboard I would wire it through the all in one as well. Their are some efficiency losses from converting DC to AC and then back to DC but the redundancy of the system allows me to bypass all my solar equipment for repairs, upgrades or maintenance and still have a the original system operating from generator or shore power or battery as originally designed. Also in a worse case scenario where the inverters batteries are depleted I still have the original 12v system fully charged and able to operate my essential devices (furnace, water pump, lights, slides, ect)

I solved this with a 6" piece of 1awg wire - jump the chassis side to the house side after cutting off the lifepo pack. And added a second starting battery for some extra capacity and redundancy.

The only other changes was to remove the isolator solenoid so the ignition key doesn't enjoin the house and chassis circuits. A dc-to-dc charger replaces it. Otherwise everything was left intact.