Solar panel mounted on roof Trillium 1300

[je.bedard]

Here's my set up for a 40w solar panel.

[Thomas G.]

It looks like you have brackets installed that partially shade the panel. If so, that could decrease the output quite a bit, especially if it is a poly / mono crystalline panel.

http://www.wholesalesolar.com/pdf.fo...lar-panels.pdf

Partial-shading even one cell of a 36-cell module, such as the
KC120, will reduce its power output. Because all cells are
connected in a series string, the weakest cell will bring the
others down to its reduced power level.Therefore, whether ½ of
one cell is shaded, or ½ a row of cells is shaded as shown above,
the power decrease will be the same and proportional to the
percentage of area shaded, in this case 50%.

[je.bedard]

Wow thanks for the tip. But my cells a running on the lenght not the with. Would that change something ?

[Thomas G.]

Originally Posted by je.bedard

Wow thanks for the tip. But my cells a running on the lenght not the with. Would that change something ?

I'd measure the output with and without the shading braces. Be sure to disconnect it from the battery before shorting the panel outputs through an ammeter.

Solar Panels - How to Test - AltE Video Tip - YouTube

[multi-task]

Meant to reply to this sooner but I couldn’t find my photo. In case you wanted a different idea, here is the panel I have mounted on my Trillium using basic z brackets (ignore the dirt and storage location under my tree). The original owner mounted it in 2004. I’ve had no issues with it to date and just the other week I drove through a terrible rain storm going through the ice fields parkway outside of Jasper.

Unfortunately hard shade will always impact a panel’s performance, I can attest to that with shadows cast from trees while camping. I make a habit of choosing north/south locations with minimal trees. I have however seen little impact from clouds unless they are storm clouds.

[theresa p]

drew---how is your panel attached to the rooftop? and does it angle at all or is it completely fixed?

[multi-task]

This one is fixed, doesn't move. Because of the shape of the roof it's at a slight angle to the back, so I try to back in facing south if possible. Often that isn't possible, so with it almost being flat it's worked out well if I'm facing another direction so long as I can avoid tree shade. When I eventually change panels I'll consider an adjustable mount, my only worry is that I would need to carry a ladder with me to change the angle.

The 4 z brackets are bolted to the panel, then bolted to the roof and covered with Dicor. Because the first owner installed the panel I'm not sure if he used a well-nut in the roof or just a regular nut/bolt. The inside of my roof has carpet so I can feel where the bolts are but can't see them without cutting through the carpet or removing it.

Wiring is run from the panel, through the roof into the cabinet space above my kitchen, then fished down behind everything so it's hidden and connected to my controller. However when/if I change panels I'll be running the wiring the other way through the roof into the closet as its easier to fish, and ends up much closer to my controller because it's at the back of my trailer (my batteries are also on the back).

Hope that helps!

[john warren]

i wonder if you could work it up as part of the stone guard for the front window? hinged so you could raise it as an awning/solar collector?
make any sense?

[RogerDat]

Seems to me the advantage of a roof mount are:

• Always charging, even while traveling down the road.
• Secured even when you out of camp.
• Storage (especially in a smaller camper) is not an issue.

Downsides are:

• The shade that keeps you cool prevents good charging.
• Wiring from roof to battery more work to do well than a portable panel with a coiled cord.
• Potential for roof leaks. (YMMV if you 3m tape etc.)
• Potential for more hassle to "upgrade" if new larger model can't use same mount points.

Note the word "potential" in the downside list.

I have a few more urgent mods and reno to do before I go after solar but I am watching and learning from the other members all the time. So especially appreciate the info on how attached and wires are run.

[multi-task]

One other negative of a roof mount is heat, which is often overlooked. Heat reduces a panel’s efficiency; I’ve watched my voltage drop on a hot day even with a small air space between my panel and roof. I compare that to an egg hovering over a frying pan, it will cook slower but it still gets cooked. That’s why I’d never flush mount a panel to any roof, that would be like putting the egg in the frying pan.
Heat would also cause issues for a more portable solution, but portable panels would likely not heat up as fast. For security and convenience mine will stay on the roof, but I might experiment with a 24v panel plugged into my mppt controller in the future to see if I can negate some loses due to heat and shade.