Solar Panels and Shedding Snow

PanamapatPanamapat Posts: 22Registered Users
Anyone have any experience with treating solar panels with silicone spray or Rainx to improve the snow shedding? Our remote cabin in the winter gets quite a bit of snow and often does not shed the snow very well. The panels are set during winter to a very vertical position to help shed the snow.

Before closing up the cabin I cleaned all 4 panels and treated one with Rainx and the other 3 with spray on Silicone spray (easier to apply than Rainx!). I don't get back often during winter, but will be curious if the coating makes any difference.

Experience from others?

BTW - last couple of winters were especially tough with early December wet snows that brought around 30 inches of snow over a few days. See picture below to get an idea of how much snow we had by late December.

071229-1338-44.jpg
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Comments

  • nielniel Posts: 10,311Solar Expert ✭✭✭✭
    Re: Solar Panels and Shedding Snow

    you may want to consider having the pvs vertical or nearly vertical to prevent the build up and mounting them high enough that the built up snow runoff won't shadow the bottom of the pvs. i can't say if the sprays hindered or helped you, but i personally would not put something on the pvs that may hinder some collection during clear times.
  • CariboocootCariboocoot Posts: 17,615Banned
    Re: Solar Panels and Shedding Snow

    Rain-X only works if there is air flow; it is a surfactant. I'm not sure putting silicon spray on PV's is a good idea either; it can be sticky for dirt and leaves.

    Most of us in the frozen climes find that near-vertical tilt + enough space for the snow to fall off to = sufficient measures. Especially if you don't use them in Winter: no big need for maximum Watts.

    Tony (Icarus) has at least one mounted full vertical to keep charge in wintering-over batteries.

    Other than "sticky wet snow" adhesion isn't a problem. Usually changes in weather, including bright sun on panels, is enough to keep them clear.
  • Dave AngeliniDave Angelini Posts: 2,161Solar Expert ✭✭✭✭
    Re: Solar Panels and Shedding Snow

    This is how I treat them in the picture. Every night they go vertical!
    "we go where power lines don't" Sierra Mountains near Mariposa CA
     http://members.sti.net/offgridsolar/
    E-mail offgridsolar@sti.net

  • icarusicarus Posts: 5,070Super Moderators admin
    Re: Solar Panels and Shedding Snow

    As Marc mentioned,

    I keep two panels mounted on hinges on the wall instead of the roof. This way when I go away there is always some Pv getting to the batteries. Other than that, I sweep the roof mounted panels after a big snowfall, mostly because I am greedy and want the power. If I wait a day or so they will clear themselves (12/12 pitch). Warm wet snow is the biggest problem. Below about -5 and the wind keeps them clear, although if we get a huge dump they can drift over.

    I would doubt that any "spray" or what have you will give you much advantage.

    Tony.

    PS. If your cabin is un-occupied for the bulk of the winter, consider a couple of wall mounts just to keep the batteries in float. If you are there on the week ends say, then just sweep them off.
  • peakbaggerpeakbagger Posts: 324Solar Expert ✭✭✭
    Re: Solar Panels and Shedding Snow

    I ran into a study one day from a group in Canada who wanted to come up with options for keeping the snow off pole mounted PV systems on remote sites. Their concept was to install black panels on the back of the PV panels. The theory was that when the sun comes out on a snow covered day, there is quite a bit of diffuse sun reflected back from the snow even at the back of the panels. By hanging the black material directly behind the panel, this reflected sunlight would slightly raise the temperature of the surface of the panels making them melt off quicker.

    I have observed this in the past that just a bit of heat (the palm of a hand) on the back of a panel is all it takes for the lump of snow on the front of the panel to slump off.

    I wish I could find a link to the study to see how well it worked.
  • PanamapatPanamapat Posts: 22Registered Users
    Re: Solar Panels and Shedding Snow
    icarus wrote: »

    PS. If your cabin is un-occupied for the bulk of the winter, consider a couple of wall mounts just to keep the batteries in float. If you are there on the week ends say, then just sweep them off.

    I've got one of my 55 watt panels mounted vertical and up very high so the snow cannot get to it in the winter. 4 of the panels (~300 watts total) are mounted with the panel bottom around 3 foot above ground at around 65-70 degree angle. I mounted them on what looks like a large erector set made of 2" pipes.

    I may find the Rainx and Silicone spray experiments will not do anything to help shed snow. But not having the luxury to regularly sweep the snow off the panels in the winter, I figured I'd try and experiment. Interesting to note that after Rainx and Silicone treatments, the panels were crystal clear but with a very very slippery surface. Will report back when I'm up there again.

    Pat
  • solarvicsolarvic Posts: 954Solar Expert
    Re: Solar Panels and Shedding Snow

    Pat I hope you update how the rainx worked for you. I am going to try some on my panels And after winter is over I will report on it too. Solar Vic
  • reedsnvtreedsnvt Posts: 1Registered Users
    Re: Solar Panels and Shedding Snow

    Solarvic/Panamapat..... any report on the rain-x? Here in Vermont, ice is my biggest problem, even with a 62.5 tilt.
    -Thanks
  • PhotowhitPhotowhit Posts: 3,216Solar Expert ✭✭✭✭
    Re: Solar Panels and Shedding Snow

    I think we have a thread where rain-X specificly does NOT recomend using it's product on solar panels. I have used their windshield wiper fluid on my panels, hoping to prevent dust from settling on them, and it seemed to work somewhat.
    Home system 4000 watt (Evergreen) array standing, with 2 Midnite Classic Lites,  Midnite E-panel, Prosine 1800 and Exeltech 1100, ForkLift battery. Off grid for @13 of last 14 years. 1000 watts being added to current CC, @2700 watts to be added with an additional CC.
  • SkiDoo55SkiDoo55 Posts: 411Solar Expert ✭✭✭
    Re: Solar Panels and Shedding Snow

    I would think that the main concern would be the chemicals de-bonding the glass to cell and letting water to get in over time? Most panel mfg's recommend only mild soap and water for cleaning.
  • mtdocmtdoc Posts: 600Solar Expert
    Re: Solar Panels and Shedding Snow

    I'm tempted to try RainX. I don't quite understand how it could damage the glass on the panels or how it could get under the glass to damage the bonding to the pv cells, etc. Seems like many have tried it. Did it work? Any actual reports of damage to panels or is this just a RE myth?

    I wish Midnite would get their snow melt feature implemented.:-)
  • PhotowhitPhotowhit Posts: 3,216Solar Expert ✭✭✭✭
    Re: Solar Panels and Shedding Snow

    Perhaps they are just worried about liability, but, About 3rd from the bottom on their FAQ's;

    http://www.carid.com/images/rain-x/info/rain-x-faq.html

    They have been using a coating to aid in light transmision (non reflective?) on solar panels so pehaps it effects that.

    I was using the rain-X windshield washer fluid on mine to help keep dust from settling on it, and I think it helped a bit.
    Home system 4000 watt (Evergreen) array standing, with 2 Midnite Classic Lites,  Midnite E-panel, Prosine 1800 and Exeltech 1100, ForkLift battery. Off grid for @13 of last 14 years. 1000 watts being added to current CC, @2700 watts to be added with an additional CC.
  • nielniel Posts: 10,311Solar Expert ✭✭✭✭
    Re: Solar Panels and Shedding Snow

    i'd be curious why none of you just didn't bypass the controller and put the battery power straight to the pvs? the pvs will drain a tad of current from the batteries and that would translate to a bit of heat to melt the snow/ice with. if you have a gt system then obviously that method won't work, but you could string up some heat tape if you really are desperate to just get the melting started thinking of directly on top of the glass, but for a more permanent heat tape install it would need to go underneath the pvs and that sounds a bit shaky to implement.
  • solarvicsolarvic Posts: 954Solar Expert
    Re: Solar Panels and Shedding Snow

    I decided not to use the rainex. Someone mentioned it might ruin the factory coating on the panels that help the absorcation of the light that helps to make electric. Just went to home depot and got an aluminum extendable handle and squegee that is for cleaniing windows. solarvic
  • ChrisOlsonChrisOlson Posts: 1,807Banned
    Re: Solar Panels and Shedding Snow

    I swept them solar panels off for the last time today for this winter. Spent almost an hour getting the snow off them this morning, got one amp-hour and then it started snowing again. When I went out to the woodpile before dark there was a foot caked on them, and they're tilted up to 15 degrees from vertical.

    I just let my other power source that works rain, shine, raging blizzard, day, or night do its job for the rest of the winter 8)

    [video=youtube_share;zNtjZa_fzxk]

    --
    Chris
  • DillDill Posts: 170Solar Expert ✭✭✭✭✭
    Re: Solar Panels and Shedding Snow

    I hear Paul Allen :)

    my panels are clear since I lowered them to vertical, there was 16 inches of snow piled on top of the frames tonight though. blah.
  • ChrisOlsonChrisOlson Posts: 1,807Banned
    Re: Solar Panels and Shedding Snow

    I don't even like Paul Allen, or football. Don't understand the first thing about the game. There was supposed to be Classic Rock on that station and what do I get? Football. I would've had it on a different station but the knob is gone off the radio so I can't change it.

    This morning there was 4-5 tons of snow about 5-6 feet deep on the shop roof behind the solar panels. It slid down and broke 4 panels. There's about a foot of clearance between the bottom of the solar panels and the roof, but not near enough room for that amount of snow in one big hard-drifted block to slide thru.

    This makes 12 that I've had busted due to snow load over the years. I used to have panels on a ground mount and they got buried under a 6-7 foot drift. I tried to dig them out and found 5 panels busted that time. I had some panels on a 8" diameter pole once and the wind tore those off and busted three - tore the bolts right thru the aluminum frames. And now I got four more on a roof mount busted.

    I've threatened for several years to just take them down and put them in storage for the winter. As of this morning that would've been by far the cheapest way to go.

    Our generator is completely buried under a drift too. I worked for a half hour this morning with the skid steer loader to dig out one end of it so I can clear the snow away from the air intake screens on it.

    Wind was straight out the north all yesterday and last night at 20-30 mph with the big Toilet Flush circulation that pulls moisture off that big lake up to the north of us. Wind from the north is the absolute worst for drifting. The wind comes over the shop roof, the panels block it and it dumps tons of snow on that roof behind the panels. Take the panels off there and we have no problem with snow buildup on the roof.
    --
    Chris
  • icarusicarus Posts: 5,070Super Moderators admin
    Re: Solar Panels and Shedding Snow

    Chris,

    Bummer!

    Being on the other side of th big lake, we don't have the lake effect issue,, we just get the cold! Mine will drift over in a big storm, but a 15" dump is big for us.

    Tony
  • ChrisOlsonChrisOlson Posts: 1,807Banned
    Re: Solar Panels and Shedding Snow

    Yeah. I think our insurance will cover the panels. They did before. But the adjuster is going to complain about not taking measures to keep the snow off the roof. But it's like, what am I supposed to do? It's not like I'm going to be up on a steel roof when the wind is blowing 30 mph trying to shovel it off. I had fully intended to get the skid steer over there, raise the bucket up and climb up in it and try to get that snow to slide off there a bit at a time with a long broom. It slid down before I got there.

    I talked to my friend NW of Thunder Bay this morning - he said you guys got like 2-4" up there.

    I think Thunder Bay is known as the "sunniest spot in Ontario". But I know you guys can get Big Snow too when the center of a low is more north and the rotation sucks moisture off that lake and pulls it north. The air gets warmed when it goes over the water because Lake Superior is so deep it only freezes over about once every 20 years. That warmed air can suck lots of moisture off the lake. Then it moves inland, the air gets cooled to the dewpoint and moisture in it falls out of the air.

    Supposed to get down to 10 below F here tonight. I have to get the generator dug out yet because if that thing starts the heat will melt the snow around it and encase it in ice and I won't get to it until spring.

    Speaking of Lake Superior freezing over, the last time it froze was in 2007. My wife and I were going to try to make it from Bayfield to Thunder Bay on the snowmobiles. We ran into pressure ridges about 30 miles out that were probably 10-15 feet tall. We couldn't get around them - followed one of them for about 10-12 miles to the east and ran into open water. Went back to the west for 30 miles and couldn't find a way over it. Finally turned back because we didn't have enough fuel left to get to Thunder Bay even if we could find a way over the pressure ridge.

    30 miles out on that lake in the winter is an experience you will never forget. Can't see land in any direction - just snow as far as the eye can see. I don't know if we're young enough (and stupid enough) to try it again the next time it freezes over.
    --
    Chris
  • icarusicarus Posts: 5,070Super Moderators admin
    Re: Solar Panels and Shedding Snow

    We are a couple hundred Km West of TBay so we don't get the lake effect.

    I flew over Superior that winter, a nd it was really cool! You could see the pressure ridges extending from shore to shore! As for running a skidoo over the lake from your side to ours... That is a task I have no interest in doing. The idea of breaking down, or running out of fuel, even with a spare machine is not my idea of fun! (not to mention the possibility of open water, or bad ice that you can't see!).

    I suspect that freezing of Superior from shore to shore is going to be a rare event in our lifetimes. Our lake just froze this week, about 2 weeks late by average, and it has been ice free as early as 8 weeks early the last few springs. You have to wish for freezing to kill the lake effect snow!

    Tony
  • ChrisOlsonChrisOlson Posts: 1,807Banned
    Re: Solar Panels and Shedding Snow

    Historically, Superior has frozen completely over about once every 20 years. When it does we get bitterly cold weather here - 50-60 below zero. I think the record was 62 below in 1979. That was before I got married and a bunch of us guys made a 40 mile run that night on the snowmobiles to a bar and grille where we ate pizza, drank beer and played pool until 2:00 AM. Our sleds were sitting outside and when we went out to go home the thermometer on the outside of the bar said 44 below. We couldn't even pull the ropes to start 'em.

    The owner of the bar let us drag our sleds into his garage and we heated 'em up with a kerosene space heater to get 'em started. Then all we all took off across the lake at 3:30 in the morning with the throttles clamped at 70-80 mph. When we got home it was 50 below.

    LOL! Man, those were the days!
    --
    Chris
  • inetdoginetdog Posts: 3,112Solar Expert ✭✭✭✭
    Re: Solar Panels and Shedding Snow
    ChrisOlson wrote: »
    Wind from the north is the absolute worst for drifting. The wind comes over the shop roof, the panels block it and it dumps tons of snow on that roof behind the panels. Take the panels off there and we have no problem with snow buildup on the roof.
    --
    Chris

    Have you considered putting some sort of paneling from the roof peak to the start of the array both to minimize air flow disruption that drops snow and hopefully to allow any accumulation to slide over the panels rather than under them?
    The filler panels would have to be designed for snow load too, and if that costs too much compared to what little power you get from the panels anyway, your idea of storing the PV for the winter make a lot of sense.
    Somebody who did not have wind or hydro might be motivated to work harder at finding a solution to the PV problem.
    SMA SB 3000, old BP panels.
  • ChrisOlsonChrisOlson Posts: 1,807Banned
    Re: Solar Panels and Shedding Snow

    Actually, I think I could just lay the panels down to their summer position, which is parallel with the roof and about a foot off the roof. I'm pretty sure they would be fine that way and not catch the wind and make snow pile up, and on the sunny days in winter I could sweep them off and still get some power from them.

    The problem with putting some sort of air dam is that it's a good 12 feet from the top of the panels to the peak of the roof. The bottoms of the panels hang over the eave so the snow will slide off onto the ground. And they're big panels - 250 watt'ers - so they stick up into air about 5 feet or so.

    If I would've gotten there right away this morning when I saw all that snow backed up behind them and gotten it off there, it would've been fine. But I saw the generator buried, couldn't get the truck out because it tried to climb a drift in front of the overhead door and the top of the cab hit the door, so it seemed like getting the skid steer going and moving the biggest drifts out of the way was more important (at the time). The temperature was close to freezing all thru the storm so it was not light fluffy snow - it was laden with moisture and VERY heavy. You pick up a shovel full of it and there's so much water in it it's blue.

    It was just "one of those things". Our insurance will cover the panels - I called them. The agent said it's a small claim, and we have had no real claims for years, so he's not even going to have an adjuster come. He said just send him a copy of the bill and he'll "take care of it".
    --
    Chris
  • icarusicarus Posts: 5,070Super Moderators admin
    Re: Solar Panels and Shedding Snow

    That's why snowmobilers die! Cold weather, cold beer and fast machines!

    Tony
  • nielniel Posts: 10,311Solar Expert ✭✭✭✭
    Re: Solar Panels and Shedding Snow

    that much snowfall with drifts is a big problem for you for sure. laying them flatter will allow that same amount of snow on the pvs that just broke a few of them. removing the pvs seasonally off of the roof would get to be a pain too. sometimes there's just no easy answers.

    btw, keep that weather up there as i don't want it. i went through h*ll here back in '09 and you probably didn't see nearly as much as what we got down through here that year. storm after storm along with frigid temps. the one storm dumped as much as to put down 20ft drifts in parts of west virginia.
  • icarusicarus Posts: 5,070Super Moderators admin
    Re: Solar Panels and Shedding Snow

    Its the heavy wet, gloppy snow that is the killer,, especially if it then gets cold! Perhaps the idea of dielectric heat tape for those rare events? Give 'em just a touch of heat for one or two days a year? Might be cheap insurance.

    Tony
  • ChrisOlsonChrisOlson Posts: 1,807Banned
    Re: Solar Panels and Shedding Snow

    That's right. If it would've been fluffy snow it would just break up and slide thru under the panels. That wet stuff makes drifts as hard as concrete that stay in one piece. When I was moving it with the skid loader it can't be pushed. I'd just drive into a bank and lift it in big 1,000 lb chunks take it off to the side and dump it, then push it up into a pile. Those piles of wet snow will set up tonight - it's already down to 2 above zero F here - and you will not move those piles even with a full sized end loader by tomorrow morning.

    It seems to me that snow slides off solar panels easier than it does on the steel roof. I've had to break up snow and get it off the roof behind those panels before and I have to really work at it to get it to slide. Snow on the panel glass slides right off just like silk. So if I'd lay them down I wouldn't get the buildup anyway other than snow that falls straight down. And I'll bet that would be easy to brush off with a snow roof rake.

    I've thought about it in the past but they're always tilted for the fall power (which is actually one of the best times of the year here. And I never think about it again until winter when they become a royal pain.

    What broke the ones I had on the ground mount the one time was the fact that snow got on the top of them and nothing underneath. The panels couldn't support the weight of the drift and it bent them and broke the glass. I didn't know it until I got them dug out. Those panels stayed working for awhile but they got water inside and burned out within about 3 months. The ones that got broke today are still working too - it just bulged the panels from the back and broke the glass. But I tested them at the combiner and they're still putting out normal voltage. None of the glass is missing on the front - it must be like glued to the solar cells or something. But it's all shattered.
    --
    Chris
  • icarusicarus Posts: 5,070Super Moderators admin
    Re: Solar Panels and Shedding Snow

    One of the reasons I eschewed a steel roof on our new place a few years ago, (even the I would prefer on!) is that I need to get on the roof all winter to sweep the panels and clean the chimney. Climbing on a steve roof with snow on it is a death wish!

    One simple solution I came up with is to glue ice and water shield on the portion of the steel between the ladder and where I need to get. (ice and water shield has a sticky back and a granular surface, making it a pretty good traction surface). The problem old BR,, if you forget which ribs had the walk way and which didn't, the next step might be the last!

    Tony
  • ChrisOlsonChrisOlson Posts: 1,807Banned
    Re: Solar Panels and Shedding Snow

    Yeah, you can't walk on it. But the snow won't slide on it either. I always lift the skid steer bucket up, climb up on top of the cab of the loader, then swing myself up on the loader frame to climb into the bucket and work from that with a snow rake. I don't trust a ladder because if a bunch of snow came off that roof when you're standing on a ladder, you'd end up on the ground anyway. When the snow slides off by itself and hits the ground sometimes it sounds like a 12 gauge shotgun when it hits the ground. I know I wouldn't want to be hit by 3-4 tons of snow when it comes off that roof.
    --
    Chris
  • waynefromnscanadawaynefromnscanada Posts: 3,009Solar Expert ✭✭✭✭
    Re: Solar Panels and Shedding Snow
    icarus wrote: »
    That's why snowmobilers die! Cold weather, cold beer and fast machines!

    Tony

    True that, but seems everyone has to learn the hard way, like smokers and cancer - - it ain't never gonna happen to me.
    But back to the original topic. Re show build up on panels. There's a very simple solution, has worked awesome for me since 2008.
    My panels are mounted on the south side of a purpose built out building with a shed roof. The rack is hinged at the top. In Spring, after the last snow storm (hopefully) the rack, and thus panels, are tilted up for best summer light collection. Then come Fall, before the first snow, I tilt them to the vertical. Sun hits them nicely, as it's low in the southern sky this time of year, PLUS, they get the reflected light off the snow covered ground, giving outputs at least as high as with Summer cloud edge effect. The slight disadvantage of having them vertical, is more than overcome by both the snow reflected light, + the total absence of any snow on the panels. I NEVER have to clean the snow off them and within 10 minutes of the sun coming up in the morning, I'm getting major amps when the ground is snow covered. After 4 years of hanging them this way I wouldn't consider any other way. Unfortunately this way of doing it is too simple for some people. They insist on going by the book instead of common sense.
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