Solar has one huge advantage, besides constantly charging the battery when the sun is out without making any noise.
The solar panels will shade the roof, so it will not be as hot inside!
SunElec.com has many 12 volt panels that can be teemed up with a PWM controller, and some home made mounts, UV rated #10 wire to bring the power from the roof down behind the refrigerator to the controller, then on to the battery.
The problem is your RV will typically use 35 amp hours daily to run the CO meter, propane leak detector and refrigerator. Most batteries are group 24 - 75 amp hours, or more likely group 27 or 31 at about 100 amp hours.
By installing a couple of 100 watt solar panels, you can put back about 60 - 80 amp hours daily, and quietly! Then you will not need as much battery capacity, as it will only be used in the night time to run the CO meter, propane detector, and refrigerator, along with a few lights. During the daylight hours, that 20 amp hours is made directly from the solar panels, and will not need to be stored.
Because you asked about batteries and a generator, I will give you information about that. 500 watts is pretty small capacity, and your stock 45 - 55 amp 'converter/charger' can use more than 500 watts. It can use between 600 and 900 watts, depending mainly how low the battery is. If you find that the battery is low, and the generator trips off due to being overloaded, you can start the truck, that will put 14 volts to the battery for a little while, then plug in the generator, it will charge at a much slower rate. After 10 minutes running the truck and generator, then you can shut off the truck, and the charge rate will be below 30 amps, (about 450 watts input to the charger) and will continue to run on the generator. After the battery is about 2/3 full, the charge rate will drop below 20 amps, and you could watch TV (a 100 watt load) at the same time the battery is charging.
Sometimes when I would run my generator, I would keep using the inverter, and run the TV from the inverter, and then be able to keep watching the show when the generator goes off. This might happen if I was cooking dinner with the microwave, or making coffee, and then run the generator for about 20 minutes to exercise it.
I have a 4,000 watt Onan generator and 70 amp charger hooked up to 4 golf cart batteries, so they have a capacity of 440 amp hours. My charger would only put out about 50 amps when the battery was less than 50% full, and only for about 15 minutes, then slowly taper to 30 amps after 60 minutes run time, as the battery filled up.
The best time to run the generator is in the morning for about 1 hour, and later in the afternoon for 1 hour. It is that first hour that the charger puts out the most amperage, then it tapers to almost nothing as the charger runs a second and third hour. To get from 35% full to 70% full might only take 60-75 minutes, but to get from 70% to 85% would take an hour or more. That last 15% can take all day, expensive and noisy when running a generator.
Good luck!
Fred.
Money can't buy happiness but somehow it's more comfortable to cry in a
Porsche or Country Coach!
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