10 replies to this topic

[ckent323]

I am new to using solar panels having just bought two of the 100 watt Grape Solar units on sale from Costco for my Keystone.

Here are some of my thoughts about mounting them.

I have Yakima racks and occasionally I carry kayaks.

It seems to me that mounting the panels on top of the camper potentially exposes the solar panels to damage as well as shading from things like trees and bird droppings. The power output is allegedly very sensitive to shading of even small areas of the panels. Also running wire through the roof of non-prewired campers seems to be an invitation to leaks (although I think my 2009 Keystone is pre-wired unlike my old 1984 Keystone).

I am wondering if anyone has used a tripod or other off camper approach to allow optimal panel positioning. This approach would work best with wires coming out the rear or the side of the camper which might help minimize risk of leaks. I think running the wires and attaching a weather proof connection may be easier too.

Storage of the panels might be done using a lockable sliding rack/shelf in the gap between the camper bed overhang and the truck cab which would also keep them protected. The panels aren't heavy but they might be a bit unwieldly so I am not sure if I would be able to get them in and out of such a rack with minimal damage risk. Also I am have not yet identified a portable tripod mount and not even sure such a thing is available.

I am just starting to think on this and have not yet identified other ways to go about it so am interested in other ideas or better yet actual projects others may have done.



Regards,

Craig

[MarkBC]

This has been done...versions of it, anyway...as a concept, at least.

Here's a link to a post I made (in a trip report) showing my free-standing PV panel and how I have it wired to a weatherproof fitting under the edge of the camper. I bought aluminum stock to build a tripod...but so far I've just used my extra chair for the same function. (I am SO damn lazy!) My main reason for going with a free-standing panel (initially) was so that I could point it at the sun and move it as the sun moved (when I was in camp).

The idea of carrying the panel under the cabover/overhang has been done, and someone has posted photos of their work here: Solar Panel Install Example. (I think this wasn't the first time that this approach has been documented on WTW, but I can't find the earlier example at the moment.) It's an idea that I've toyed with...and bought aluminum stock to do...but haven't done yet. Now that I have 240 watts of panel-power permanently mounted on the roof, I may not bother with using my 80-watt panel, so don't need a way to carry it.

It's true that shade on a panel reduces its output out-of-proportion to the fraction shaded...so maybe a consideration for those who camp in tree-ish areas.

Regarding the potential for damage when mounted on the roof: Yes, there's a chance. But I don't recall anyone on WTW reporting any such damage to theirs, and all manufacturers of RVs put PV panels on the roof...I'd say that the risk of damage is acceptably small.

Have you seen/reviewed the Ultimate Solar Thread? It's a collection of links to lots/most of the WTW topics posted by folks related to solar power on/for their campers. Probably more than you want to read...but doesn't take long to skim the photos...if you haven't already.

[ckent323]

Marc,

Thanks for the reply and the links. I recall seeing the picture of those (your) panels but did not recall what thread it was in. That was the genesis of my thoughts about a portable tripod or something.

Maybe attaching the two panels together in an aluminum frame with a fold out pair of legs, secured by adjustable chains or something, thereby creating an "A" frame type setup would do the trick. I think I will have to make the frame and panels separable since each panel is 20+ pounds.

Thanks for the link to the slide out too. That is very close to what I had in mind (although holding two removable panels instead of one permanently mounted).

I think it is interesting, given all the pictures I have seen of folks carrying canoes, Kayaks and other things on the roof, that no one has posted anything about solar panel damage, the need to take things on and off to use the panels or the problem with shade (we like to park under a tree canopy whenever we can to keep the heat down inside). Pehaps it is not the hassle I think it is and even low risk. Looking forward to seeing more comments on this.

I will go back and read more of the Ultimate Solar thread. I do not recall any discussion of this in there but I don't think I read all of the posts.

Thanks,

Craig

[MarkBC]

...the problem with shade (we like to park under a tree canopy whenever we can to keep the heat down inside). Pehaps it is not the hassle I think it is and even low risk. Looking forward to seeing more comments on this.

I will go back and read more of the Ultimate Solar thread. I do not recall any discussion of this in there but I don't think I read all of the posts.

WARNING: I'm not an expert on photo-voltaic cells AT ALL! (I am an engineer, but not an electrical engineer) This is just my interpretation of what I've read.

From what I've read the shade effect can be significant -- for example, if 20% of the panel is in shade, then you may lose 60% of its output (just making up those numbers, but it can be as big as that). It depends on what part of the panel is shaded... There can be "bypass diodes" in place to reduce this effect (even my cheap Solar Cynergy panels have these), but those diodes are only between groups of cells, not every one, so you may only lose one group by shade...but if the shade lies across all 3 (typically) groups then you can lose a lot.
I think there are folks on WTW who know the subject well...maybe they'll chime in.
Here are a couple of links on the subject:
The Effect of shade on Solar Panels
Shade Happens
Diodes in PV Systems

Personally, I'm only mildly concerned with the shade effect because most of my camping is in areas with little shade...and I don't seek it out when there is shade.
Seems like solar may not be a good solution for folks who mostly camp on what's called in the PNW, "the west side" -- the land of firs and ferns.

[craig333]

My kayak goes on the opposite side of the solar panel. If I needed to haul more stuff yes it would shade the panel but the panel sits slightly lower than the mount so it won't get damaged. Thats custom stuff, not sure how they sit when fwc does it.

[Ted]

Regarding the potential for damage when mounted on the roof: Yes, there's a chance. But I don't recall anyone on WTW reporting any such damage to theirs,

It happens. I understand someone was trimming trees over Simimike's XP and damaged a solar panel with a falling branch. But Mike's a nice guy and understands people make mistakes so isn't naming names or laying blame. No sense in beating oneself up, er, uh, beating up on the guy.

[MarkBC]

Shh -- It happens.

A confession (just a little off-topic...): I broke my original solar panel, totally shattered the glass.
My truck was parked at the edge of the paved part of my driveway. I'd placed my PV panel leaning against the rear bumper, mostly vertical, but leaning at enough of an angle -- with the glass-side "up" -- that it would stay there OK (or so I thought). Well, it was windy, and the wind shifted (or something) and it was strong enough to push and tilt the panel... When I came outside the panel was lying glass-down on the pavement. OMG! I tearfully (OK, not really) lifted my poor panel to see the damage: Shattered glass all across the panel. Yes, it's tempered glass and break resistant (if such glass wasn't break-resistant, folks who live in hail-prone areas couldn't use solar panels), but there are large bits of gravel on my pavement, here and there, and the weight of the panel drove a couple of those gravels into the glass as it came slamming down!
So sad -- especially 'cause this was NOT a cheap Chinese panel. Live and learn: PV panels can break.

[buckland]

Here's my original post... http://www.wanderthe...55/page__st__10 and http://www.wanderthe...hp?/topic/6155/
The tripod center is how I raise the roof. The setup works great when one wants to camp in the shade and have the panel in the sun... and I always have the 2 canoes on the Yakimas so it just makes sense for us.

[Kodachrome]

The idea of carrying the panel under the cabover/overhang has been done, and someone has posted photos of their work here: Solar Panel Install Example. (I think this wasn't the first time that this approach has been documented on WTW, but I can't find the earlier example at the moment.)

You might be referring to my post, except mine is a 100 watt that slides in and out without a ground brace and like the other one, can come out for low angle sun work. I have a 135 watt on the roof so this combo is pretty darn good, I did the upgrade back in mid 2011, might be where the other guy got the idea as I came up with it on my own:

http://kodachromeproject.com/blog/archives/496

[ckent323]

Buckland,

Perfect! That is exactly what I had in mind. Now I need to sort out if I can use a variation of your approach for two Panels.

Have you had any isseues with wind? If so how do you make the tripod and panel safe from blowing over?

Thanks for responding.

Craig