New roof-mounted solar panel

[peterh]

I've always liked the idea of solar power for our trailer, but didn't like the hassle of setting up and placing panels next to my trailer each time, or the worry about them walking off. Big RV units often have them permanently mounted on the roof, so I set out to do just that. I haven't installed the solar charge controller yet (it arrives tomorrow), but the new installation produces 3 amps of power at 16.8 volts for a total of 50.4 watts under the the noon-day summer sun.

<July 9 Note: Our Sunsei charge controller arrived today and I installed it this evening. The panel generates 1/2 amp at 14V (7 watts) in the late afternoon shade provided by the tree in our front yard.>





First, the solar panel. I hunted on eBay for a couple months looking for a 50 - 55 watt Siemens solar panel. I wanted Siemens for two reasons; First they have an excellent reputation for producing power even when the sun is not at an ideal angle and on cloudy days, and second their 50-55 watt panels can be arranged so they're four feet long by just over a foot wide, perfect for fitting between the "hump" that runs down the middle of my trailer and the awning housing.

What I found was a home-made kit panel (assembled from Siemens components) with a wood frame for $260, including shipping. I was a little concerned about ordering over eBay, but the seller had a long history with an excellent reputation with almost all good feedback. (And I always check the most recent feedback comments.)





The wood frame for the panel was in sad shape, but that was OK by me, because the panel worked fine and I planned to build my own frame of 1x4 composite "wood" trim anyway. (Composite wood because it is made for outdoor applications in wet locations, so it won't rot.)

First I made a template of the roof profile where I planned to mount my panel and cut five ribs to match that profile, two end-cap ribs and three middle ribs to support the glass-like structure of the panel so it doesn't crack. Next I cut 4' long side rails so they'd skim about 1/8" above the roof of our trailer, and put a 1/4" deep groove 1/4" down from the top edge of the end-cap ribs and rails for the panel to fit into. I also cut angle pieces to reinforce the corners of the panel sub-structure.





I dry-fit all my bits and pre-drilled the screw holes I needed to hold it all together, pulled it all apart, re-assembled it without the panel, screwed it together and put it up on the roof so I could test-fit it to the trailer and mark the rib locations on my roof, then I spray painted the panel frame with Rustoleum white, took it apart, put marine silicon in the 1/4" deep grooves and re-assembled the complete panel structure using urethane glue at all the joints.

While the glue was curing I drilled the screw mounting holes in the roof: three 1-3/4" stainless steel screws for the front rib and two into the middle and back ribs. When the panel was ready to mount I connected it up to the wiring I had pre-installed using water-tight connectors, put a liberal dollop of marine silicon at each screw hole and held the panel in the right position while Lynne used the drill from the inside to loosely screw the first screw in. Then I did final positioning, loosely screwed the rest of the mounting screws in. Lynne climbed up to the roof and pressed down on the panel frame over each rib to snug the panel to the roof as the screws were fully tightened.





--Peter

[Greg A]

Very nice installation Peter.
I like where you tucked it in behind the awning.

[peterh]

Very nice installation Peter.
I like where you tucked it in behind the awning.

I like that, too. You have to be back a ways or standing on something to see the panel behind the awning housing, otherwise you'd never know it was there. I'm hoping that, tucked to one side of the awning cover and a few inches rear of the 'fridge vent the panel will be more aerodynamic, too.

--P

[Donna D.]

Ya better bring a ladder to the Oregon Gathering Peter...bet there's going to be some folks that will want to check out this mod... up close and personal

[peterh]

Ya better bring a ladder to the Oregon Gathering Peter...bet there's going to be some folks that will want to check out this mod... up close and personal

But Donna, what's the point of having a solar panel that's tucked away where you can't see it if you bring a ladder so people can look at it?

--Peter

[Joy A]

I wanna see I wanna see

I have the very same solar panel as you. I've contemplated mounting it on my 13 footer between the 2 vents. I really didn't/don't like the idea of it straddling the hump.

I never thought about between the hump and awning. I'll have to check to see if there is enough room on my 13 footer.

If I had room in the Jeep or Scamp I'd bring my own ladder. You know I bet there's a big rig with a ladder that I can borrow. "There's more than one way to skin a cat." Or should I say "You should never have let the cat out of the bag."

[Joe Z]

Peter....
Really great job that siemens panel fit in there so nice........ i was lookin at a kyocera panel now you got me to thinkin
thanks for the input
Joe

[Herb P]

That's a great mount Peter..

I put my Siemens 50w panel straddling the hump on my 1700 while I had the insulation out... I made two backing plates out of aluminum and #8-32 nutserts and glued them to the ceiling... The length of the panel is such that the backing plates live just toward center of where the hump starts to curve down so I figured it should be close enough. Then I screwed the panel brackets through with stainless steel #8-32 screws and blue threadlock. This way I can remove the panel any time and reinstall it. The panel brackets stay on the roof and I can still remove the panel, or some subsequent owner of the trailer can remove the brackets completely leaving only 3 easily plugged holes. For the connector, I used a milspec AMP bayonette water proof connector. I figured I could remove the panel if I'm boondocked somewhere shady, and place it somewhere sunny...

front/rear placement is just behind the front vent... My theory was that would keep as much windage from the panel as possible so it wouldn't put any strain on the brackets while driving...

You can sort of barely see it here:

http://www.beer.org/gallery/Boler17-refresh/IMG_5488

[peterh]

I put my Siemens 50w panel straddling the hump on my 1700 while I had the insulation out... I made two backing plates out of aluminum and #8-32 nutserts and glued them to the ceiling... ... My theory was that would keep as much windage from the panel as possible so it wouldn't put any strain on the brackets while driving...

Same general idea, doing our best on the aesthetics while keeping it at least somewhat aerodynamic.

Our Siemens panel had no problem keeping up with our electric usage this weekend. It'll be interesting to see how well it keeps up during the fall and early spring when there are fewer hours of daylight and more clouds in the sky.

On a side note, I saw someone using one of those cheapo $150US 900 watt, 2-stroke generators at the airshow this weekend. Similar to this one. It was actually pretty quiet, though he did say that it was sometimes a pain to start. Got me thinking . . .

--Peter

[Brian B-P]

On a side note, I saw someone using one of those cheapo $150US 900 watt, 2-stroke generators at the airshow this weekend. Similar to this one. It was actually pretty quiet, though he did say that it was sometimes a pain to start. Got me thinking . . .

At the airshow? How quiet does a generator need to be to be acceptable at an airshow, home (along with biker rallies) of the last holdouts of publically operated unmuffled engines?

I think an evaluation in the conditions of a campground, where it should be possible to distinguish the calls of birds and not just the sounds of radial verus inline engines, would be preferable.

P.S. I'm a big aviation fan... I just don't expect quiet at airshows, and don't want engine noises at campgrounds.

Neighbors with [b]solar panels...
Neighbors with typical generators...

[peterh]

At the airshow? How quiet does a generator need to be to be acceptable at an airshow, home (along with biker rallies) of the last holdouts of publically operated unmuffled engines?

I agree the threshold at an airshow is lower, but the two of us were conducting a conversation in our normal voices five feet from his running generator, and the generator just quietly put-put-putted away. Was it noisier than a Honda 1000w unit? Yes. Was it way quieter than I expected a $150 generator to be? Yes to that, too.

Do I prefer silent-zero-fuel-and-fumes solar? Absolutely. My plan is to have enough solar to meet our needs during the late spring, summer, and early fall months when we do most of our camping. If, however, we decide to do dark-season camping, which would mean using our low-draw LED and CCFL lights more but our Fantastic Fan very little, and find we don't have enough juice, a $150 genset might be just what we need to get over the hump.

I'll cross that bridge when, and if, I ever get there.

--Peter

[peterh]

We found out last September that our single 50 watt panel wasn't quite enough to keep our trailer powered up enough to run the furnace all night in the 20 degree nights of Yellowstone, so I added a second roof-mounted panel on the street side of our trailer.





This panel is another Siemens unit, 55 watts this time, that we got off of eBay. It brings our total solar capacity to 105 watts . . . but is limited by the fact that both panels are bolted to the roof. I'm just too nervous about loosing an expensive, remotely placed panel to some five-finger discounter . . . but given the single 55 watt panel was almost enough to keep us in a Clean, warm, and Well-Lighted Place I'm sure this will do the job for us.

[kevin61]

Looks good Peter. You should have plenty of juice with panels permanently mounted flat. I am finding that my setup works fine, flat on top of the Boler. I might not have to remotely mount them at all.

[Stretcher]

Hi Peter,
I am relatively new to RVing and not electrically savvy. I have 2011 Scamp 5er and would like to closely replicate your solar system and have numerous questions.
1. How did you make the template for the roof contour? Are all ribs the same?
2. Did you remove the cabinets in order to screw the ribs to the roof? If so, any problem with leakage at the replacement rivets?
3. How did you route the wiring, outside and in?
4. Where are the charge controller and the inverter mounted?
5. Are you still using the Scamp installed converter/charger?
6. Where did you install the Olympian Wave and how is it fueled?
I will appreciate any help you can give me. If you would rather talk on the phone instead of writing a book, let me know when and where to reach you.
Thanks, David