Foretravel Owners' Forum For owners and Fans of Foretravel Motorcoaches February 28, 2026 ...

You need to spend several days reading all you can online and don't be in a hurry.  Don't try and reinvent the wheel and learn from others mistakes. I like commercial panels as they are built like tanks. 39 inches wide and about 77 inches long with a 1 1/2" thick aluminum frame. About 52 lbs so they will take a lot of abuse from trees, wires, etc. Most will be 36 volts so four panels in a series parallel wiring with bring about 72 volts in only four wires down to the the controller. Could do all parallel and have more wires coming down. All series would bring 144 volts in only two wires but on a cold morning, the voltage would exceed 150 volts and is discouraged by controller manufacturers as well as giving a possible fatal shock to the installer or during maintenance. Figure about 1 1/2" clearance between the bottom of the panel and the roof at the lowest point on a curved roof or 1 1/2" under a flat roof like ours.

96" coaches need more planning as the 3 inches on each side make a difference.

A good MPPT controller will get about 2/3 of the potential wattage from the panels in summer.

Our coach with LED lighting and 4K TV never needs the generator with less than 500ah house battery bank. Propane fridge and no AC.

Pierce

I fit six 320 watt panels on my 34 ft U270.
Lessons learned:
1. Get Sunpower panels, model X22 370 watt panels are the most durable and efficient (22%), and well worth the cost.
2. Don't bother tilting them. Just add more panels.
3. I used VHB tape and aluminum brackets, which is working well after 2 years of outdoor use and 16,000 miles.
4. Leave at least 4 inches above roof. This aids in cooling and allows cleaning.
5. The panels can stick out over the side of the rig up to the mirrors. I did this and they cleared every obstacle.
6. Install as many panels as you can fit. On cloudy days, power is reduced by up to 90%, so you'll be glad you have the power.

I used 4- 300watt panels like Rogers, they are on one charge controller. I then saw I had more room and bought 2- 360watt LG panels and have them on there own controller.
I glued 2"x3" aluminum rectangular bars (5200 sealant) and then installed 3 hinges on a side of all the panels. They are now able to raise. With limiting cables on each they can be tilted forward past 90 degrees and left that way so I have almost total room to walk the roof to perform any maintenance. 3- 300 watt panels are tied together and lift as a unit on the drivers side. 3 panels monted on the passenger side each lift separately. They can be tilted from the ground using a pole to lift each of them and latching them into position.
The 3 panels tied together lift with a 12v scissor jack mounted in the middle of the 3. The jack has a wired hand controller and a wireless controller so they can be lifted from the ground also.
With the hinge mounts the panels are easy to remove if needed, just pound the hinge pin out and the panel is free to come off.

Last month I mixed two LG 335 with two LG 280 watt panels on my roof.  Now, I have 1187 watts, up from previous 560 watts.  63.8 Volts times 18.61 amps, equals 1187.31 watts.
I am using 4 LG panels with two 280 w panels installed two years ago at one end, (the front,) wired in series, and at the rear of the roof, two LG 335 w panels wired in series, both groups to combiner box on roof in parallel (so, 63.8 volts to controller) and down refrig vent to single mppt charge controller rated at 1400 watts at 12 volts. 150 volts/100 amps.
I choose one solar controller over two separate controllers because of reduced cost and the fact I could then use all the existing wiring without any additional wiring.  By doubling the voltage down the refrig opening, existing wire was fine.  Two controllers would have only yielded  43 more watts on the roof, 1230 vs 1182 watts.
The math was as follows.  Max power of 335 watt panels 34.1 (max power volt, VMPP) x 2 = 68.2 V x 9.83 (max power current, MPP) = 770 watts.  LG 280 31.9 volt x 2 = 63.8 v x 8.78 = 560 watts.  In parallel 63.8 volts (lower of two parallel voltages) x 18.61 amps (combined amps) = 1187.31 watts from my roof system.
Mounting hardware, wire, and combiner box were all from AM Solarin Springfield, Oregon.

There is no such thing as a "modified sine wave inverter." How can you modify a sine wave? It's nothing more than a &#@! advertising term when it should be called a modified square wave inverter.
Pierce