How many 240w solar panels can you fit on 34fter?

The panels are approximately 3' x 5'. It really depends on the other stuff on the roof but I could easily fit 3 of those panels on the roof of my 32' FW. You have to get up on the roof and look to really know

You can probably fit a lot more wattage by using a smaller panel. I have some 120 watt, 75 watt and pair of 45 watt panels on my roof, total of 415 watts, and it all fits in a 30' Bounder motorhome. With A/C, three roof vents, two antenna's as well.

SunElec.com

SolarOnSale.com

Good luck!

Fred.

Run a remote cord. 25 ft or so, you camp in the shade, panel is in the sun.

Hi,

The roof configuration is different on many brands of RV's. My panels are 53.8 inches by 29.2 inches and I have four of them on the roof in non shaded locations. I would have room for five.

Take a piece of cardboard cut to size and climb on the roof. Do this in the morning between 9 and 10 a.m. Park the RV perpendicular to the sun to create the longest possible shadows. After checking, turn the rv 180 degrees and check again. Shade of any kind, even from a radio antenna is not acceptable.

It would probably hold a bunch, but access to other stuff should also be considered. Cut several pieces of cardboard to size and place them up there. Watch for potential shadowing.

I haven't purchased the trailer yet, so I can't climb up yet but the cardboard idea sounds very good - will do that when the time comes. Thanks for the ideas!

Hi Acei,

Visit the local dealer and climb on their roof *grin*

Solar panels come in all kinds of sizes, and also different voltages. You need the right application for the job you want to do.

If the voltage is between 19 and 22 volts "Open Circuit" then it is considered a 12 volt nominal panel, and can be used with a low cost Pulse Width Modulation (PMW) solar controller, I bought a 10 amp one for $13. To use a higher voltage panel in a 12 volt application, it would require the more expensive MPPT controller. Maximum Power Point Tracking is something that came out around 1996, where the solar panel's maximum voltage is used to charge the battery, while the controller is used to convert the 19 volts to 13 volts at a higher amperage. So 10 amps at 19 volts can be converted to 13 amps at 13 volts.

Today, MPPT controllers can take in 40 volts and put out the desired voltage output, even if set up for 12 or 24 volt battery. And some models can take in as many as 150 volts - so the solar panels can be wired in a string, for the minimal voltage loss, and then wired to the controller that way.

Yet I would not recommend sting wiring for a RV solar system. The problem is that if there is a small shadow on one panel, it can reduce the maximum potential amperage of all the panels in that string. And you know how RV's like to be under trees sometimes. In a house, that is normally not a problem.

SunElec.com - link above, has 12 volt panels, PWM and MPPT controllers. They also sell a lot of home based systems, with 39+ volt open circuit ratings, so the ones over 22 volts would require a MPPT controller.

Fred.

As a side note, I put 4 each 100 watt solar panels on a Holiday rambler fifth wheel, and barely covered any of the roof. So installing a 500 + watt system is really practical, as far as roof coverage.

I made my own mounts, with 6" long pieces of 2" aluminum angle metal, with 3 each 3/16" holes on one side and one 5/16" hole for a 1/4-20 bolt into the solar panel frame on the other. This lifts the solar panels about 1" off the roof, so cooling air can get under it, and keep the temp down. Cooler panels make more power.

Fred.