I know this isn't what you want to hear but I though I would toss it out just the same.
I wonder if, maybe, you wouldn't be better off selling your large panel and getting several smaller panels instead?
Sorry to rain on your parade, but that's my three cents (inflation) worth.
Once you get your panel(s) installed, you will love solar.
This is also my thought as well. There comes a time when we throw good money after bad. Respectfully, you received some bad information on your panel choice. I hinted at that in my post as to why I had two 65-watt panels, not one 130-watt panel. I hesitate to post more, out of concern of making some folks angry. What I can tell you without hesitation, is my two 65-watt panel, BlueSky controller, one 100 AH AGM battery with the Trimetric does everything the wife and I need done. If I had your rig, I would do it the same, possibly different panel sizes depending on space. Just too many experts giving you advice. Pick one, cross your fingers and hope for the best. If their rig is not relatively close to yours in size and solar needs, you may have the wrong expert.
I encourage you to read http://handybobsolar.wordpress.com/about/. I think he does a real good job of explaining, even though I do not necessarily agree with everything he says, particularly on batteries. He starts out by explaining his frustration/anger in discussing solar on Forums.
Here is some food for thought,
any possiblity of using that panel as a sun shade of the back window, tilt adjustable, would kill 2 birds with 1 stone, so to speak.
Might make things easier untill you get some more experince etc.
2010 F-350,6.4PSD, 6spd man trans,CC,SWB,SRW, Caravan camper shell,50 gal bed tank,17,000lb Husky WD hitch,Northwoods 2008 28KS Desert Fox Toy Hauler,2005 Honda 500 Rubicon ATV w/rumble seat,1 Aussie waiting,watching and ridin shotgun on the whole outfit.
I recently installed 4 panels each 210 watt. Physical size about 39 X 65 inches each. Voltage 29V. I needed this size to get the watts I wanted up top. I bought a Midnite Solar charge controller. This panel size is used mostly by residential and the price per watt is very much lower that the smaller 17V panels. I did also mount mine up off the roof about 8 inches to the top of panels from the top of the roof to minimize shadows and get the the back 2 panels over the top of the luggage rack both on the curb side and the back by about 3-4 inches. I saved enough on the four panels to nearly pay for the top of the line mppt controller. I used 2 inch square aluminum tubing for all mounts instead of aluminum angle. Very strong and less expensive than big box store angle. I bought it from a place that sells materials for use in building 'Arizona/Florida 3 season rooms". Worked out great for me. TED
Hopefully you'll try it first and let me know if it works out or not!
Edit: I posted this partly with tongue-in-cheek but after thinking about the possibility of causing a freeway pile-up, I really think that it's better to keep the panels as close to the roof as possible. Creating a huge pressure difference between the top and bottom of the panel could create some tremendous lifting forces.
* This post was
edited 03/29/12 04:29pm by Ktuck *
I would not worry about the A/C shadow on the huge panel, you should be getting plenty of solar power even with a little shade on one section of the panel. Point the RV north to avoid shading, and you probably want to do this anyway to avoid getting a lot of sun into the front windshield.
I would not recommend hanging the panel any more than the 4" required off the back of the RV. By using solar mounts like I have, and a 12" long 3/4" angle aluminum, you can unbolt the north side of the panel, and attach the tilt arm, it will enhance the solar gain by about 15%, but I would only do this if staying put more than a week, and only if the battery is showing signs of weakness. If you are fully charged by 11 am, no need to consider tilting the panel. It is probably much better to stay off the roof anyway!
At first I was planning on using some sort of vertical bracket to hoist them up a couple inches, but it seems like there's plenty of breathing room for them underneath as it is, except for in the middle. At the edges it's about 3 1/2 ".
I'm thinking about just bolting the angled brackets together as it is. Would that leave enough room for ventilation?
I'll worry about a tilting mechanism later if I need to. I kinda just want to get it on there for now...
I think you are heading in the right direction. You mentioned the panel is about 25" wide? If so, get two pieces of 2" angle aluminum the width of the panel + 2", rivet them on to the forward and rearward sides about 10" in from the sides of the panel, and then bolt equal size 2" angle to the roof. You can have one bolt on the front and back about 1" outside the edge of the panel, and then use tilting brackets about 10" long when you want to tilt the panel.
Space the screws through the roof mounted angle aluminum about every 5" or anyplace you think there will be a roof structure underneath. Keep the rearward screws about 6" forward of the rear cap, just to prevent any leaks there, you have plenty of room to bolt down the panels without having to bolt it there too. Use lots of rubber roof sealant to hold down the brackets to the roof, then put in the 5-8 screws into the roof, and coat the screw heads with more rubber roof sealant. Once the rubber roof sealant has dried, you can mount the solar panel on the roof, it will stay put with 4 bolts between the two brackets (panel mounted one and roof mounted one).
This is how I mounted the 2" angle to my forward outside edge of my solar panels, and it seems to hold really well for over 10 years.
This is the mount it is held on with three rivets into the frame, and then the bottom half is 4" long aluminum, with nutsert in the upper piece, bolt you can not see from the outside edge pointing inward.
Hi, I too think you are headed in the right direction. I agree with others that it would be best NOT to mount it above the AC. The mounting bracket becomes considerably more elaborate than a normal mounting, plus it would have made the solar panel the highest part of your RV, meaning if you were to hit something (such as a tree limb when backing in somewhere) the panel would get raked off or damaged. And I think having a panel up that high would have looked quite odd.
I also wouldn't worry about shadows on the panel from the AC. The sun would have to be on a low angle towards the front of your vehicle in order for a small shadow to even hit the solar panel.
I would be inclined to lift the panel up just a tad (say a half inch or so) so it doesn't touch the roof in the center - that will prevent it from abrading the roof due to vibration while traveling. I think it would be best to have the support brackets be the only thing touching the roof.
I wouldn't consider trading it for a smaller panel -- I think it fits OK in the space you have it, and it looks OK. Hanging off the back 3 or 4 inches is no big deal (it is probably still inside your bumper line). Once you get suitable mounts figured out, it is going to be a nice install. I think those standoffs someone else suggested may be a good thing. Those bolt thru the roof into the interior, increasing the mounting strength. I would bolt up thru the ceiling, using big fender washers under the bolt heads (paint the bolt heads and fender washers first to match the ceiling). You would of course need to do some pre-measuring to make sure you can bolt thru in an un-obstructed area.
Good luck on your install -- that looks like a great panel. I assume you have a suitable controller/regulator for it.
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edited 04/03/12 02:46pm by NetBoy *