I'm Thinking of putting a solar panel on our trailer, but I don't think I know enough about them, is it easy to install one, What do I look for, and what are the prices about? and how big of a system do I need, we just have a 22' travel trailer and have 1 12v battery, and we camp for about a week at the most.
Oh and the sun does shine here a fair bit.
2008 Jeep Grand Cherokee with 3.0L diesel.
2005 Chevy Silverado 1500 4x4
2010 195wbs Shadow cruiser travel trailer.
For now, unless you have lots of money, I'd invest in an extra battery or two. Get some deep cycle Marine batteries, and see how you do with them.
A solar system can bet quite pricey, and the question will be, do you want it to charge your batteries, or to run some stuff in the RV too? The more load you put on things, the more panels you will need, and that is when it gets expensive. Solar controllers and such will only add to the bill.
Harbor Freight has a small system that might be a good starter, but if you have intentions of putting any load on it, you'll need more.
As far as installation is concerned, you just want a flat area on the roof, and a good sealer, for the screws you put through the roof
Bill & Claudia / DD Jenn / DS Chris / GS MJ Dogs: Sophie, Abby, Brandy, Kahlie, Annie, Maggie, Tugger & Beau RIP: Cookie, Foxy & Gidget @ Rainbow Bridge.
2000 Winnebago "Minnie" 31C, Ford V-10
Purchased April 2008 FMCA# F407293 The Pets
For solar to work well the range of wattage is best between 60 and 150 watts of panels per 100 amp-hours of storage. Less than 60 watts may not be able to equalize the battery bank (but even 12.5 watts per 100 will, given enough time, fully charge the bank). There are reasons to use more than 150 watts (such as possible elimination of other charging sources)--but after the battery bank is 85% charged there is not much point in attempting to charge faster than the c/8 rate (exception AGM batteries).
Charging a battery bank is somewhat like a frog on a log who can jump 1/2 to the end of the log in any jump. Every jump takes about the same time but the amp-hours returned to the battery become smaller and smaller. That's why solar, with a good charge controller, is one of the better ways to recharge batteries. It is not uncommon for me to see my solar panels "putting in" just one amp to 875 amp-hours of storage.
For small solar (up to 500 watts), I very much like the Rogue Controller. It may be cheaper to buy more panels and use a lower cost PWM controller (so long as it includes a three stage charger, and a temperature sensor), but that will add extra weight and require more holes in the roof.
My RV uses about 35 amp hours a day to run the refrigerator, propane and CO detectors. Add to this about 1 amp hour for each hour you run a light, and about 6 amp hours (AH) for running the furnace a hour. TV can be another 8 AH per hour, if using a small inverter. Laptop is only about 2 AH.
I have a pair of 120 watt solar panels, they each make about 35 AH. This is a great start. Start with what you can afford, and add some more later. You might want to look at a simple 15 - 20 amp charge controller that takes in 12 volt nominal (up to 21 volts panel output voltage) and charges the battery, only shutting it off when it reaches 14.0 volts, and turns back on at 13.5 volts. This is the least expensive charge controller, while the MPPT controller claims to give 10% more power, it is also a lot more expensive.
However if you select a 24 volt or higher nominal voltage (output under load will be 36 - 44 volts) then a MPPT controller can take that higher voltage and put out 13.3 volts to the battery to charge it, and will take in say 5 amps at 32 volts and put out about 11 amps at 13.5 volts.
I have made my own roof mounts, click "View Posts" under my name, and type in "Solar" and you will find I have posted on several recent solar questions, with pictures, and mount instructions.
First look at some panel dimensions and see what will fit. I assume you want 100w to 200w with only a single battery. This will be one or two panels generally. When you measure watch for shadows from anything already on the roof. Shading just one cell can decrease panel output significantly so don't cram the space.
Here are some panels to get dimensions and start planning: