Tilting solar panels February 20, 2001, 06:56:06 pm Yahoo Message Number: 2197The solar panels are secured to the roof by brackets which are screwed down. These screws, covered by sealant, are not disturbed.On most rigs, the bracket is L shaped, with one screw thru the vertical part of each ell into an outside corner. If you remove the screws at two corners (front and rear curb side, for example), you can lift the curb side edge of the panel, since the screws in the street side brackets will act like hinge pins.Many LD owners at Quartzsite had their panels tilted towards the sun. Typical numbers were 1.5 to 2A for a flat panel, 3.5 to 3.8 A for a tilted panel. Local vendors even sell add-on metal arms to hold the panel in its uptilted position.On my rig, the upper ends of the brackets are screwed into the *underside* of the solar panel, a few inches in from each panel end. I can't see any way I could tilt mine except to loosen the roof-mount screws, which I'm not even tempted to do!
Tilting Solar Reply #1 – February 20, 2001, 07:03:29 pm Yahoo Message Number: 2198Bob P writes: Solar panels transfer more energy when they are perpendicular to the sun's rays. When the sun is just grazing across them, there is virtually no output -even in bright sunshine.Hi Bob--That's what I thought, too. During the buying process, I asked about whether the optional solar panels were tiltable. Ed Newton told me they weren't because there would be no reason to make them tilt; they'd work fine flat on the roof. I took him at his word and ordered LD's solar panels.I think if I had it to do over again, I'd get my solar panels from a specialist like solar city or real goods.
Tilting Solar Reply #2 – February 20, 2001, 07:25:58 pm Yahoo Message Number: 2199This discussion is all very interesting. Wonder how many times a day you would need to adjust the tilt to maximize the perpendicular relationship with the sun's rays?
Tilting solar panels Reply #3 – February 20, 2001, 08:04:13 pm Yahoo Message Number: 2201Hi,I would prefer the stock LD installation at build time for security of the mounts in high winds. It does not seem to me like a great idea to loosen the panels.What about this: for a winter boondock of more than a day or two, consider climbing up and rigging some flat reflectors perpendicular, on the north side of the panels. Not as good as actually tilting the panels, but it would certainly improve the efficiency, and be less invasive. Say you are at 37 degrees latitude (e.g., San Jose, CA -- what an ugly place, why are you there, anyway? ::smirk:, and the sun is declined an additional 23 degrees at the dead of winter -- that makes for about 60 degrees off of the zenith at noon, right? Then the reflector would only have to be 1/2 as high as the panel is wide, to cast a reflection that would cover the panel. To be effective from about the beginning of november to the beginning of february, I think the reflector would have to be about the same height as the panel is wide. It would not be worthwhile the remaining months -- at that latitude, anyway. Just an idea that I will pursue with my LD to see what real increase in charge amperage I can gain. If somebody who works with solar on a regular basis wants to check my work and offer corrections or confirmation, that would be great.--Valerie
Tilting solar panels Reply #4 – February 20, 2001, 08:43:38 pm Yahoo Message Number: 2203I think that the effectiveness of a solar-electric panel varies with the cosine of the angle of the sun from perpendicular to the plane of the panel.In the early days of solar (when I was closer to the technology), folks built tracking systems to keep the panel normal to the solar flux. It is easy to point the panel, but hard to keep it from blowing off of the mount.At 30-deg off-normal, you are getting about 86% of the panel's maximum output for the weather conditions. Probably close enough.Ed Newton probably found that a horizontal panel worked ok without the complication of adding a pointing system.Bravo to Valerie, another heroic member of the club. I'm looking forward to your test results.bob phillips
Tilting solar panels Reply #5 – February 20, 2001, 08:48:47 pm Yahoo Message Number: 2204re; How often to adjust the angle of solar panels: If one were to try keeping the panel above 86% effectiveness, they would need to be adjusted every time the sun shifts 30-deg in the sky.360deg/day divided by 24 hours/day = 15-deg/hour, so we'd need to climb up and move the panel 60-deg every four hours -about 6-times a day.Maybe its better to buy a second panel and just leave it flat.bob phillips
Tilting solar panels Reply #6 – February 20, 2001, 09:22:48 pm Yahoo Message Number: 2205Or .... use the hydraulic jacks and tilt the LD to follow the sun. Of course you'd have to shut off the fridge. ;-)
Tilting Solar Reply #7 – February 21, 2001, 12:01:33 am Yahoo Message Number: 2208"Maximizing" solar ouput would require continuous adjustment of the panel. However, significant (winter) gain is achieved simply by tilting the panel up to about 45 degrees and leaving it there until the end of the campout.When it's time to travel, the panel is returned to horizontal and all screws tightened--there is nothing left loose up there.
Tilting solar panels Reply #8 – February 21, 2001, 12:46:28 am Yahoo Message Number: 2209Bob: I don't think you have to adjust the panel during the 14 hours between sunset and sunrise :-)I think that, on a scale of 0 to 10, realistic expectations are: Continuous adjustment of angle = 10 Park rig east west and tilt panel to 45 Deg = 8Leave panel flat = 3.Note, this is important only for winter days when you want to take advantage of the little sunshine you get. In summer, days are longer and the sun is higher and a flat panel works fine.
Tilting solar panels Reply #9 – February 21, 2001, 10:34:54 am Yahoo Message Number: 2216"I think that, on a scale of 0 to 10, realistic expectations are: Continuous adjustment of angle = 10Park rig east west and tilt panel to 45 Deg = 8Leave panel flat = 3."This seems pretty accurate to me, but on the condition of full exposure. This is a condition difficult to achieve in the winter, except with a broad expanse of desert and the mountains DISTANT. I generally find that even if it is a clear shot nearby, even trees aways off will block the sun when it is at winter's azimuth.Add to this the reduced effectiveness of cold batteries in accepting charge, the shorter days and thus greater 'inside' time (more lights, etc), we generally find that with our two (flat) panels, we do best to hit the road every couple of days or so while dry-camping.Still, wouldn't be without them - even a small replenishment is helpful with conservative ways.Steve
Tilting solar panels Reply #10 – February 21, 2001, 06:37:50 pm Yahoo Message Number: 2225For those interested in solar design and technology, try this web site: [url=http://www.lazydazeowners.com/[url=http://worldwideclassified.net/rvdesign/Click on the "Solar Array Features Space-Age Deployment Pattern" link.Also, my solar and electrical links may be useful: [url=http://www.lazydazeowners.com/[url=http://www.calpoly.edu/~gharvey/RVLsolar.html~Greg
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