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+1 on PNW_Steve's suggestion to put panels over plumbing vents. Cut off the rain lids from those vents and use the panel as the new lid. I've also overhung the side of the RV by a few inches, especially in areas where there's already a protrusion from the RV (over side view mirrors, plumbing inlets on the side, etc). I've even seen people make racks to mount panels over AC units. That's especially common in Europe interestingly, where I think there's more of a functional utility approach to the roof of an RV than America, where people tend to try to keep things neat and tidy.
But looking out at a bunch of RV and trailer rooftops right now all I see is blank real estate. I don't see a single one that couldn't fit two 300 watt panels easily, most of them even more. And I don't see a single modern panel, just a couple of small old style 12 volt panels. And their generators are already running in the middle of the day even though it's cold enough here on the Northern California coast that most people are wearing jackets.Last edited by Wrybread; 09-02-2019, 01:44 PM.Comment
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Ha! It seems like a lot of us keep getting extremely lucky around here. The way we keep beating all these impossible odds we should all meet up in Vegas!Comment
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A decent 300 STC W panel rates out at ~ 17.1 STC W/ft.^2. --->>> 2400 STC W/17.1 STC W/ft.^2/ = ~ 140ft.^2 clear of shading and obstructions when horizontal. Might work, depending on vents/penetrations/vehicle size. Don't know what a design that considered wind loads might require.Comment
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Odd to see it written as if we're reinventing the wheel here... This is all really basic stuff.A decent 300 STC W panel rates out at ~ 17.1 STC W/ft.^2. --->>> 2400 STC W/17.1 STC W/ft.^2/ = ~ 140ft.^2 clear of shading and obstructions when horizontal. Might work, depending on vents/penetrations/vehicle size. Don't know what a design that considered wind loads might requireLast edited by Wrybread; 09-11-2019, 02:28 PM.Comment
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Plumbing vents and ceiling vents will come after the panels. I am dealing with a less than ideal environment and trying to make up for it by overpaneling. I have roughly 8' x 35' space to work with.
I am not entirely sure what the wind rating is. I expect them to be able to tolerate the 65mph wind. That would be a common condition when mounted on my house.Comment
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Where I spend most of my time we get insane winds from the south during storms. My weather station registered gusts to 80 knots during one of them. Somewhat funny aside: my neighbor was installing four 280 watt panels on his new-to-him RV a few months ago (280 watts because he's that cheap, I think they were $80 each), and they weren't bolted down yet. Right when the front was passing and all hell was breaking loose his panels started flying into my camper! Just missed one of my windows. That sucked.
But I've never had, or heard of, a problem with bolted down panels, on any RV whether it's stationary or driving through super heavy Santa Anna winds. I'm embarassed to admit I've lost multiple surfboards off my roof, but never a solar panel, in 25 years of having them up there.Last edited by Wrybread; 09-11-2019, 05:29 PM.Comment
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Ha!After many years in the casino industry I discovered the only machine in the casino that paid out regularly was the on with the big sign above it "ATM".
My rig is a 24 foot class C. I had to cover two plumbing vents to fit my three 310 watt panels, but they were just pvc pipes with lids that were easily sawed off making the panels the new lids. One of my panels overhangs a few inches over my passenger side and had to be mounted at a slight angle to make things fit, but other than being a bit of an eyesore (I actually think it looks beautiful, ha) it's no biggie since the side mirror sticks out way more. And of course it's a small price to pay for near infinite power.What sort of rig are you installing solar on?
I keep meaning to install a 4th panel, but that means either losing the loveseat that I keep permanently mounted on my roof's cargo area (at the rear where the rack is), or covering the light vent (the kind that cranks open) above my shower. There's no urgency since my 3 panels give me all the power I need even through winters, but I'm totally off-grid with no generator or connection to my alternator (I never run my engine anyway) so an extra panel would come in handy in the dead of January when we get stormy weather for weeks at a time. There's no urgency since my system has gotten me through 3 winters in a row at this point, but I'm a bit worried about my battery bank (4 Trojan T-105s) since they're now either 5 or 6 years old, which is obviously pretty long in the tooth. And I'm a huge fan of being able to get maximum charge during those tiny breaks in the storms.
Are you running all your panels into a single charge controller, or breaking things up into multiple? I'm using a single Morningstar MPPT-60, before that a Tracer 40 amp MPPT. The Tracer worked fine but the Morningstar fell into my lap. And what's your battery bank?
Last edited by Wrybread; 09-11-2019, 05:19 PM.Comment
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@Mike90250: By the way I was wrong when I responded earlier saying I get about 500 watts max. I hardly ever look at my charge rate anymore since it's all set-it-and-forget-it, but your question made me watch more. I've been getting a max of 650 watts (about 50 amps @ 12 volts). Once this battery bank dies I'll either go 24 volt lead acid or, hopefully, high voltage lithium, which should get me a significantly higher charging rate. But what I'm getting has been working really well for me so no biggie.When you are charging well, what sort of PV harvest do you see, 300w? 500w?Comment
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Well, this is not a stationary mounting. The panels will usually take a wind load. It's the design and method of attachment(s) that are usually overlooked that usually causes more problems, particularly if the panel supports are designed to be off horizontal when stationary. Also, what happens if you're driving at 60 MPH into a 40 MPH headwind, etc. ?
BTW, it's probably not the best thing for the panels to have stink/moisture vents under them. Doing so will also probably/potentially screw up the draw for the vents.Comment
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Out of curiosity, do you own an RV? Of course we've all been in the above situation a million times, never so much as a whimper from my panels.Also, what happens if you're driving at 60 MPH into a 40 MPH headwind, etc. ?
In real world use it works just fine. Solar panels are tough and a little extra air flow on their back sides is probably actually *good* for them. And as long as you leave a little gap over the top of the vents (duh) those vents work just as well as before they had panels over them. Again there's no reason to get theoretical here, there's lots of people who've been mounting solar panels on their RVs and trailers for decades without any problem from the above.BTW, it's probably not the best thing for the panels to have stink/moisture vents under them. Doing so will also probably/potentially screw up the draw for the vents.
That's not to say people don't have to be careful when mounting panels of course, but it's super super super easy to do well. I've had good luck with this stuff:
(Or lately I just cut beefy aluminum angle iron into short strips, which is even easier to work with)
And then cover the screws with good ol Dicor Lap Sealant:
Last edited by Wrybread; 09-12-2019, 02:13 AM.Comment
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Since you ask, no, only one eye, one balloon knot and a fair amount of experience designing structures for wind and other external loads.
As for it working just fine, I'm sure it does and will continue to do so until it doesn't.
I'm not the world's engineering police , but saying something works just fine now gives you some responsibility for what others reading your stuff may go and do.
But, NOMB. Your RV/life/whatever.
Take what you want of the above. Scrap the rest.Comment
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