Where to mount solar panels on roof?

Harry1954 wrote:
Why is everyone putting big heavy panels on their trailers when their are light weight flexible panels that are monocrystalline with marine grade aluminium sheets? Doesn't this just add considerably extra weight to the GVM of the trailer?

Link?

Everyone isn't,......only the big straps.

Why is everyone putting big heavy panels on their trailers when their are light weight flexible panels that are monocrystalline with marine grade aluminium sheets? Doesn't this just add considerably extra weight to the GVM of the trailer?

Take a look at your roof and measure the open areas. Also decide where you want to have the wiring for the panels enter the trailer and go to the charge controller and from the charge controller to the battery bank.

Ideally you want the charge controller as close as possible to the batteries as the top priority, and then to minimize the length of the run to the roof where you will mount a C-box or combiner box where all the wires from the panels are joined/combined.

The panels need to be mounted where they will not be shaded by anything on the roof, like a TV antenna or dish, or the AC unit. For shading purposes you can use an angle of 30 degrees from the top of the AC for example to see how far away to mount the panel.

Panels come in different lengths and widths which is another consideration in terms of maximizing output. The larger the Watts ouput of the panel the lower it will be in cost per Watt. All the panels should have the same Voc output so you cannot use a 17 volt panel along with a 34 volt panel.

Once you have the area selected you can use your measurements of the available space to select the panels and the layout that will work the best.

Generally speaking it is easier to mount a frame that can hold 3 panels side by side than it is to individually mounting each panel.

There are lots of posts with pictures by people of their RV solar panel installations and mounting setup. Very worthwhile to take the time to see what others have done and why they did it one way or another.

RV solar panels are smaller and more expensive than what you could put on your house. RV solar specialty outfits include amsolar.com and
http://www.solar-electric.com.

The charge controllers are made for use with houses and rural situations and not for RV use. As a result most will have terminal connections for small gauge wires which is the opposite of what is ideal for RV installations. One exception is the Blue Sky 3024 controller. The 3024 also has an option for a remote settings management and monitoring device so you don't have to be able to see the 3024 charge controller to see the charge state of your batteries or to change a setting.

Thanks, I think what they sell are as good as any.. their construction is good. If I can get 2-3 hours sun I get plenty of juice for us. We recently took a 12 day trip to Michigan U.P. with no electric the whole trip. We camped in the shade and on sunny days it still helped, not enough to keep. Then moving to the next campground it charged up most of the way. We had enough battery to never be a concern.

Hi Heap64,
How are you liking those Renogy modules? They seem to be a good bargain. Looked through your installation pics, again, and anybody contemplating a solar installation could follow your thread and see how it should be done.

FWIW, I have a four-way tilt that I built but, if was doing it again, would have just made it two-way. The 4-way may come in handy at some point but I store at home so parking angle isn't a problem with direction. On the road, I leave the panel down.

RJsfishin wrote:
I wonder why not mount the panels close to the edge, like in the one photo ??
There would be much less chance of shading from objects on the roof, and no chance of the panels shading each other if or when tilted,.....like will for sure happen in the one photo above. It would really be defeating a purpose if you were to tilt a panel, only to be shading the panel next to it.

I doubt I will ever tilt ours. It might be different if I camped over the winter for weeks at a time. But for us they do the job flat. I would rather have them a little further from the edge to have less chance of branches bothering them.

At today's cost of panels just add one more and you won't need to get on your roof again.

I wonder why not mount the panels close to the edge, like in the one photo ??
There would be much less chance of shading from objects on the roof, and no chance of the panels shading each other if or when tilted,.....like will for sure happen in the one photo above. It would really be defeating a purpose if you were to tilt a panel, only to be shading the panel next to it.

Mine are 80W - I mounted them as far forward as possible and near the edges on our motorhome:



They could have had a bit more underside space to accommodate circulation, but they do fine for our needs.

Looks like you have lots of space, but as others have mentioned, make sure no shadows fall on any part of the panels. Even an antenna whip shadow will cause the entire panel to cease output.

Getting them a little higher off the roof helps with items causing shade issues. These are 100w Renogy panels about 3" off the roof. I get little shading staying about a foot away from the vent covers.


25Y Roof with 5 100w Renogy Panels