Solar(s) Panel(s), wich choose?

[Uplander]

Discovered ways to roof mount panels without drilling holes through roof.

Also learned that a space of about 2 inches is recommended between solar panel and roof surface for cooling of panels as heat buildup results in loss of power in solar panels....high heat=lower output.

[Gordon in Idaho]

I'd like to make a few more comments on this topic, in response to what others have mentioned.

Cost: We all have our priorities when it comes to spending money on our FGRVs. I didn't spend a lot to buy my 72 Scamp, and I haven't put a fortune into it. It was just a solid shell on a new axle when I got it. Perfect for me. Blank slate. I've concentrated on interior design and comfort, mostly. On the outside, it still looks like an old 72 Scamp (except for those shiny panels ).
"Overbuilding" is not a fault, it just costs a little more, but not That much more. For me, solar power on my trailer is a grand science project....from those invisible, excited electrons all the way to cold beer in the fridge, I'm fascinated. So, like a hobby, I don't mind spending some money on something that is so much fun. Don't get me wrong, I'll waste hours on the internet trying to save a few bucks.

Extension cords: Most of the panels systems I have seen use MC4 connectors, which are solid and waterproof, and require a special tool (cheap) to separate them. I'm not sure if rigging extension cords would save much money, considering the crimping, soldering and shrink tubing that would be needed to make them suitable as weather-proof connections. And then there's the quality of the wire itself and the shielding that is used. The wires provided by Renogy are excellent, in my opinion.

Mounting or not mounting: Adding a remote, moveable panel is something I considered for months. The advantages of doing this are obvious, but the drawbacks may not be. How do you store this panel when moving, unless it's suitcase style, or you build your own case, or have the room to wrap it up and tuck it away safely. When you're on the road, a stored panel does nothing but take up space. Since I depend on solar for my fridge, this would be a disadvantage to me. Then there's the chance of theft. Solar panels look cool, and I think some people think they're worth more than they are. A panel on the ground might be a tempting heist to some.
And, one more thing.... I just might drive off dragging a panel behind me. But I guess that's a personal problem .

So, you've decided to mount to your roof: I trust expansion nuts (well nuts), and they work for me. I used 4 for each 100w panel. Big advantage: can be installed by one person using one wrench, and can be removed without a lot of trouble, if neccessary. Big scare: drilling 1/2 inch holes in your roof.

Flexible panels: Another option to consider, but read the reviews and compare the prices and warranties.

Performance: Photo voltaic cells begin working at sun-up and don't quit until sunset. Like hard working farmers, I suppose. They work in the shade and on rainy days. Just not as well. My point is this: they don't shut off. The amps are cumulative. On a bright, sunny day in June, my battery may be fully charged by 9-10 AM, and the panels have nothing to do for a while. Under less perfect conditions, it may take all day. And...., dusty panels can under-perform just like it's a cloudy day.

And so ends another long-winded post on solar. Obviously a favorite subject of mine. I try to share reliable info based on experience and research, but my education never ends. And I don't mind being called out on anything I've said. After all, I've been wrong before. Once or twice.

Gordon

[RogerDat]

I have an awning track attached with VHB tape, not seen a whole lot of use but some fairly stiff breezes and my awning tarp is 10 x 12 so I would guess the tugging force is fairly high. However solar is typically attached with stand off brackets with not a large amount of surface area in contact with roof. That would be the issue I would want to address. Maybe with a rail or something that uses VHB that the stand-off brackets attach to. If I was attaching I would go with the larger panel.


30/40 watt panels are small enough to stow. You can Velcro strap them to fiberglass wall of closet. I like being able to park in the shade but move panel to sunlight, while being aware that as Gordon points out that is one more piece of stuff to be stowed or left at risk if I leave camp.


This seems like a question for one of the EE's but since driving down the road I have the battery being charged by the vehicle alternator how does that impact the solar charging. I'm assuming that the charge controller in effect being between the two charge sources will have an impact, just not sure what that impact would be.


Trolling motor plugs are another good and inexpensive option for connectors. I was mostly wondering about wire size in an extension cord. Seems to me since I plug into 110 volt source with an extension cord having one for portable 12 volt panel source would not be a big difference.

[Jon Vermilye]

Originally Posted by RogerDat

I have an awning track attached with VHB tape, not seen a whole lot of use but some fairly stiff breezes and my awning tarp is 10 x 12 so I would guess the tugging force is fairly high. However solar is typically attached with stand off brackets with not a large amount of surface area in contact with roof. That would be the issue I would want to address. Maybe with a rail or something that uses VHB that the stand-off brackets attach to. If I was attaching I would go with the larger panel.

In the past, Escape used 1" square aluminum tubing the length of the narrow side of the panel to attach the panel to the trailer & act as a standoff. The early trailers used VHB tape to attach the square tubing to the trailer, and they later changed to epoxy.

My panel is attached with VHB tape (installed in April, 2011) and it is still solid. They have had 2 failures that I know of that have been discussed on the Escape Forum, one with the tape & one with epoxy. In the case of the epoxy failure, the gel coat separated from the trailer fiberglass shell; apparently, the epoxy didn't fail. Both failures were while driving in severe crosswinds. In any case, they provided owners with additional attachment kits & are now bolting the panels to the roof.

[honda03842]

I've had a solar panel attached directly to the Scamp 16's roof surface (gel coat) with Scotch exterior vhb tape for about 5 years. No issues what so ever. I was able to remove two 40 watt panels and replace them with a single 100 watt panel. No damage to the surface. We travel pretty extensively in all kinds of weather. One advantage is our panels are no more than a 1/4 of an inch off the roof surface.

Sent from my SM-N920T using Fiberglass RV mobile app

[Gilles]

Originally Posted by honda03842

I've had a solar panel attached directly to the Scamp 16's roof surface (gel coat) with Scotch exterior vhb tape for about 5 years. No issues what so ever. I was able to remove two 40 watt panels and replace them with a single 100 watt panel. No damage to the surface. We travel pretty extensively in all kinds of weather. One advantage is our panels are no more than a 1/4 of an inch off the roof surface.

Sent from my SM-N920T using Fiberglass RV mobile app

Thank you very much for your positive comment, fix the panel with VHB tape, this is how I decided, having read and seen a lot about ...

Having secured with tape 3M VHB RP25 2 inches wide, I protect from dirt, sun and weather, with a layer of the protective tube.

Have a good season.

[Steve Outlaw]

Long standing recommendations for the mounting of solar panels suggest a 3-4 inch air space under the panels. The air space under the array helps lower PV module temperatures; cooler modules produce more electricity than hotter modules.

[Radar1]

Originally Posted by Gordon in Idaho

And I recommend this controller because it shows you real time amps in and amps out; amp hours in and amp hours used; among other useful stuff. It's very good to know how much current the sun is providing, as well as knowing how much electricity you're devices are using:
P30L LCD 30A PWM Solar Panel Regulator Charge Controller with Digital Display and User Adjustable Settings
When you add in mounting brackets, extension cables, and battery cables, it's not cheap but, there's a unique joy in using the power of the sun.

Happy camping,

Gordon

Hi Gordon,
I have the same controller as you. Have you connected your LOAD lines into your 12 volt system yet? I'm a bit fearful of doing that because it seems that any charging done by either the converter when on shore power, or TV while towing, would go directly back through the LOAD output. Would that damage the controller, or would adding a diode prevent any potential damage?
I did run a separate circuit from my LOAD output to a dedicated circuit for my 12 volt outlets, used to power my TV/DVD and CPAP machine, plus reading light and radio. That way I'll be able to measure how much power those devices consume immediately and cumulatively.
I would love to tie the whole DC circuit in so I could also measure the pumps, other lights, and fans.

My current setup includes a 90 watt panel permanently attached to our 16' Scamp roof with VHB tape, and a portable 90 watt panel that can be set up wherever the sun shines to help the permanent panel as needed.

[Gordon in Idaho]

Hi John,

I can only give you a partial answer. Yes, everything that requires electricity in my Scamp is fed off the Load terminal of the controller. I use this fuse panel, located about 10 inches from the controller:
Amazon.com : Blue Sea Systems ST Blade Fuse Block - 12 Circuits with Negative Bus & Cover : Fuse Block With Relay : Sports & Outdoors
I have 10 of the 12 branch circuits in use, plus this sub panel in the back of the trailer with 4 more fused lines.
Amazon.com: Sea Dog 422010-1 Aluminum Vertical 4-Switch Panel: Automotive
Miles and miles of wire....

I called Windy Nation last year with questions about using the Load output as opposed to running everything directly off the battery, and I was told that it's OK as long as you don't draw more than 30 amps. Don't try to hook up an inverter this way!

I like being able to isolate different devices and learning how many amps they use. One of these days, when I'm sure my battery is top shape, I'll have to stress the system by turning Everything on at the same time, and that means fridge running, all lights on, furnace blowing, water running, DVD playing through the amplified stereo system, and charging a phone and Kindle. I'll let you know what happens.

But, I don't have any means of using shore power or my TV's alternator, but I would Assume they would provide regulated power directly to the battery, and not feed back to the controller. As i understand it, if the controller reads a full battery, it stops providing charging power until needed. Maybe another forum member will be better able to answer that question.

So, that's what I Think I know. I'm not sure about all the science involved, but I know what works for me.

Gordon

[Gilles]

Originally Posted by honda03842

I've had a solar panel attached directly to the Scamp 16's roof surface (gel coat) with Scotch exterior vhb tape for about 5 years. No issues what so ever. I was able to remove two 40 watt panels and replace them with a single 100 watt panel. No damage to the surface. We travel pretty extensively in all kinds of weather. One advantage is our panels are no more than a 1/4 of an inch off the roof surface.

Sent from my SM-N920T using Fiberglass RV mobile app

Hello to both of you,
I just want to check with you if I shopped the perfect tape to secure my solar panel.

3M VHB RP25 (2 inches wide)

Temporarily out of stock on Amazone.ca

https://www.amazon.ca/TapeCase-Width...5rp+2%22+width

The Z Brackets of the panel to stick on the roof have as 1.50 inches by 4 inches area.

[Radar1]

Originally Posted by Gilles

Hello to both of you,
I just want to check with you if I shopped the perfect tape to secure my solar panel.

3M VHB RP25 (2 inches wide)

The Z Brackets of the panel to stick on the roof have as 1.50 inches by 4 inches area.

Gilles,
I used the same VHB RP25 tape, except mine was only 1" wide. I used a 1x1x36" aluminum angle piece cut into four 9" sections for each leg and bolted the Z brackets to them. (9 sq inches of surface area at each corner)
I had to bend the brackets a little from perpendicular due to the side to side curvature of the Scamp roof, and the front brackets were modified to also meet the increased front curvature of the Scamp roof. From the photos you can see that 1/3 of the front angle had the upper section cut away so I could bend the foot to the curve.
One lucky part of having the Scamp with the large fridge is that it includes an upper vent, so I was able to run my solar wiring down that vent without resorting to any new holes in the Scamp roof.

[Gilles]

Originally Posted by Radar1

Gilles,
I used the same VHB RP25 tape, except mine was only 1" wide. I used a 1x1x36" aluminum angle piece cut into four 9" sections for each leg and bolted the Z brackets to them. (9 sq inches of surface area at each corner)
I had to bend the brackets a little from perpendicular due to the side to side curvature of the Scamp roof, and the front brackets were modified to also meet the increased front curvature of the Scamp roof. From the photos you can see that 1/3 of the front angle had the upper section cut away so I could bend the foot to the curve.
One lucky part of having the Scamp with the large fridge is that it includes an upper vent, so I was able to run my solar wiring down that vent without resorting to any new holes in the Scamp roof.

Thank you very much for your testimony.
For my curiosity and that of other members who are interested about, what capacity your solar panel and your apreciation of it?
Thanks in advance,

[Radar1]

Originally Posted by Gilles

Thank you very much for your testimony.
For my curiosity and that of other members who are interested about, what capacity your solar panel and your appreciation of it?
Thanks in advance,

We have a 90 watt panel on the roof that fills our needs when we have sunlight, plus another 90 watt panel we can deploy up to 40 ft away if the sun isn't hitting our camper.
So far we have been happy with the results using our type 29 12 volt battery but hope to upgrade to two 6 volt golf cart batteries next battery change for double the capacity in case we run into dark rainy weather further North. Less sunlight up North in the winter months.