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Do you bother with snow removal from roof panels in winter?

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  • Do you bother with snow removal from roof panels in winter?

    I have both roof and ground mount panels. The roof panels have been covered with snow for a week or two and if anything like last winter it won't melt off until March. The roof is single story. If I remember I clear the ground mount each time it snows.

    Do you bother trying to clear the snow, or just live without the power from those panels? I bought a painter's pole something like 23 feet long my first winter and tried to clear the panels with a foam brush type thing on the end. At full extension the pole was going to bend or outright snap so I just took the pole back to Home Depot.

  • #2
    I have three arrays. Two are easy to clean with a rake. The third one is on second floor roof. I can get to the bottom edge of the roof and lower foot of the panels with a pole. Once I expose the shingles under the array and the lower edge of the array. If the sun is out, the snow will start sliding off a lot quicker than not doing so.

    Comment


    • #3
      My experience, the weather may be best for PV solar right after a storm (usually at night).
      So yes, I am out at first light getting them cleaned off. This is most likely in April, right
      after my net metering reset date, with no summer reserve to heat with. I do not do a
      super neat job, the sun will finish that once it hits the panels.

      The whole system is being optimized for 2 seasons, snow vs no snow, to increase
      production and to optimize snow rejection at the same time. However, this entire action
      on these easily reached ground mounts, is quite unlikely for a roof mount. Bruce Roe

      Comment


      • #4
        Originally posted by bcroe View Post
        The whole system is being optimized for 2 seasons, snow vs no snow, to increase
        production and to optimize snow rejection at the same time. However, this entire action
        on these easily reached ground mounts, is quite unlikely for a roof mount. Bruce Roe
        Do you just like to read your own posts as you are constantly replying with stuff that has no relevance to the question asked? I asked about clearing roof mounts, not ground mounts. Yes, we all know you are in love with ground mounts.

        I have both roof and ground mount and I already clear the snow from my ground mounts. Even with the snow cleared I didn't get a single watt generated today. There is a very thin layer of snow still stubbornly stuck to my ground mount panels that didn't melt today.

        Comment


        • #5
          Originally posted by reader2580 View Post

          Do you just like to read your own posts as you are constantly replying with stuff that has no relevance to the question asked? I asked about clearing roof mounts, not ground mounts. Yes, we all know you are in love with ground mounts.

          I have both roof and ground mount and I already clear the snow from my ground mounts. Even with the snow cleared I didn't get a single watt generated today. There is a very thin layer of snow still stubbornly stuck to my ground mount panels that didn't melt today.
          You can always ignore what Bruce writes.

          Take what you want of the above. Scrap the rest.

          Comment


          • #6
            Originally posted by reader2580
            Do you just like to read your own posts as you are constantly
            replying with stuff that has no relevance to the question asked?
            Fell free to ignore and delete any of my useless info. Never had a zero KWH day here.
            Bruce Roe

            Comment


            • #7
              12.2kW here in NJ (Solar Edge). All on second story roof so not easily accessible. We don't usually have a lot of snow here in NJ, just a few inches a few times per year. So no, I do not attempt snow removal. My array faces South so once the sun comes out and things start to melt it usually avalanches pretty well on its own.

              I would be concerned about potentially cracking/scratching the glazing, particular if there had been some melt/sleet and things start to ice up.

              I think the longest my array has been offline due to snow is maybe 2 to 3 days. And then by the third day, once I had enough Optimizers powered up (as some of the panels had self cleared) things started to come back to normal.

              Not really a big deal, for me, production in Dec-Feb is pretty low anyway.

              Comment


              • #8
                Originally posted by JSchnee21 View Post
                12.2kW here in NJ (Solar Edge). All on second story roof so not easily accessible. We don't usually have a lot of snow here in NJ, just a few inches a few times per year. So no, I do not attempt snow removal. My array faces South so once the sun comes out and things start to melt it usually avalanches pretty well on its own.
                The big issue is the white snow just reflects the sun. The dark panels don't help when no sun hits the dark part. I probably have three to four inches of very dense snow on my roof panels right now. Last winter I went for two to three months with zero production from my roof due to snow. Snow was as deep as a foot and I remember that March 15th was the day the snow finally was gone from the roof.

                Comment


                • #9
                  Even just a half inch of snow will pretty much shut down panels. That brilliant white snow reflects a lot of light away.
                  Powerfab top of pole PV mount (2) | Listeroid 6/1 w/st5 gen head | XW6048 inverter/chgr | Iota 48V/15A charger | Morningstar 60A MPPT | 48V, 800A NiFe Battery (in series)| 15, Evergreen 205w "12V" PV array on pole | Midnight ePanel | Grundfos 10 SO5-9 with 3 wire Franklin Electric motor (1/2hp 240V 1ph ) on a timer for 3 hr noontime run - Runs off PV ||
                  || Midnight Classic 200 | 10, Evergreen 200w in a 160VOC array ||
                  || VEC1093 12V Charger | Maha C401 aa/aaa Charger | SureSine | Sunsaver MPPT 15A

                  solar: http://tinyurl.com/LMR-Solar
                  gen: http://tinyurl.com/LMR-Lister

                  Comment


                  • #10
                    I wonder what they do in Europe. Lots of solar in snowy Alpine countries. It's a shame you cannot run the inverter "backwards" and push some grid current through the panels to heat them up so that the snow melts.

                    I wonder if that electrical resistance heating tape they make for pipes and stuff would damage the panels if was places under the panels or along the frames.

                    Some folks have advocated treating the glazing with high quality anti-rain type coating like Aquapel Glass Treatment By PGW (not that RainX junk). But of course this will likely void your warranty.

                    You could try calling the panel MFG (not sure what brand you have) and see what they suggest. Even manually clearing the snow might "void your warranty."

                    Comment


                    • #11
                      It would be quite hard for a panel manufacturer to differentiate panel damage from general environmental effects and effects from proper occasional cleaning of snow. The reality is with rare exceptions few if any manufacturers will be around to care what happens to the their panels as they will no longer be in business and any warranty will be worthless.Two of my arrays were built out of panels bought from bankrupt companies and the manufacturer I bought my original array from long ago sold the business. My arrays are getting on in years with one 17 years old and another 12 years. I have seen no damage to the surface coating from cleaning with a plastic roof rake. Maybe some companies uses a "tender" coating on their arrays to boost the initial efficiency clams but expect other environmental issues would remove the "tender" stuff in a few years.

                      My somewhat long term experience with panels in a snow belt is that I remove snow because I want to not because I have to. Snow conditions vary widely storm to storm and day to day. If the snow doesn't come off in a day or so, a couple of warm days and cold nights will establish a crust which tends to lock in the snow for weeks unless there is a major warm up. I have found that by exposing the shingles at the base of my shallow roof array and the lower 1 foot of the panels I will take advantage of the day time sun and helped by some heat loss from the attic, frequently that will be enough for the snow to break loose. The annoying part is my racking system has hardware sticking up at the gaps between panels. They may not look very big but they are enough to hold the snow for a few hours. A subsidiary concern with leaving snow on panels is as the snow builds up partially thaws and refreezes is it gets quite heavy, when it inevitably breaks loose it does a lot more damage. I think the approach that is used for steel roofs in snow zones should be used, If there is any potential damage that can be done by unexpected snow slides then snow brakes should be installed. Few is any solar installers worry about this and usually it only gets done after a few scary events.

                      If I really need to depend on PV generation in the winter I would put the panels vertical under an overhang. Panel angle is not that important in winter with snow on the ground as the snow is quite effective at reflecting sunlight onto panels, add in cold temps and mine usually put out above nameplate rating on a cold sunny winter day. With some creativity a vertical wall mount array can be made adjustable, I have one that could but there is angle bay window that limits it from full vertical. I helped with another one with the same design but its not lit up yet so I cant check performance. It is capable of 60 plus degrees of motion.

                      Comment


                      • #12
                        Originally posted by JSchnee21 View Post

                        Not really a big deal, for me, production in Dec-Feb is pretty low anyway.
                        I was looking into an extendable brush like the one linked below to at least reach my lower arrays...nice that it could double for window washing, etc. but havent pulled the trigger yet.

                        https://smile.amazon.com/dp/B07HGJ9T...v_ov_lig_dp_it
                        71qi-LymEGL._AC_SL1500_.jpg



                        December has been pretty horrible for solar production so far here in NJ, well below the calculated average between the heavy cloud cover days, rain and a couple small snow events.

                        Only at 190 kWh so far with my 12.35 kW system.
                        Last edited by NJturtlePower; 12-17-2019, 10:27 AM.
                        12.35 kW - https://pvoutput.org/list.jsp?sid=67749

                        Comment


                        • #13
                          Originally posted by JSchnee21 View Post
                          I wonder what they do in Europe. Lots of solar in snowy Alpine countries. It's a shame you cannot run the inverter "backwards" and push some grid current through the panels to heat them up so that the snow melts.

                          I wonder if that electrical resistance heating tape they make for pipes and stuff would damage the panels if was places under the panels or along the frames.

                          Some folks have advocated treating the glazing with high quality anti-rain type coating like Aquapel Glass Treatment By PGW (not that RainX junk). But of course this will likely void your warranty.

                          You could try calling the panel MFG (not sure what brand you have) and see what they suggest. Even manually clearing the snow might "void your warranty."
                          It is possible that the angle of the roof is much steeper in Europe which should help with snow removal.

                          IMO if someone has the $$ to install a pv system in snow country then maybe they should have thought about how to keep the panels clean and purchased the proper cleaning tools to make it happen and still be safe.

                          Comment


                          • #14
                            Originally posted by JSchnee21 View Post
                            I wonder what they do in Europe. Lots of solar in snowy Alpine
                            countries. It's a shame you cannot run the inverter "backwards" and push some grid current
                            through the panels to heat them up so that the snow melts.

                            I wonder if that electrical resistance heating tape they make for pipes and stuff would damage
                            the panels if was places under the panels or along the frames.
                            Putting tape around the edges of panels is not going to be effective. The experiment was done
                            here years ago, feeding power directly into the panel element. With the power at 3 times the
                            panel rated output, the snow was unaffected. I gave up.


                            PVmelt.jpg

                            I see the basic problem as the panel having so much area exposed to the air. Just maybe,
                            insulating the back side could help but still not practical. How would you ever feed that much
                            DC power back, more than the array is rated?

                            700 KWH so far this Dec from a 15KW system with DC to AC of 2. Bruce Roe

                            Comment


                            • #15
                              Originally posted by peakbagger View Post

                              If I really need to depend on PV generation in the winter I would put the panels vertical under an overhang. Panel angle is not that important in winter with snow on the ground as the snow is quite effective at reflecting sunlight onto panels, add in cold temps and mine usually put out above nameplate rating on a cold sunny winter day. With some creativity a vertical wall mount array can be made adjustable, I have one that could but there is angle bay window that limits it from full vertical. I helped with another one with the same design but its not lit up yet so I cant check performance. It is capable of 60 plus degrees of motion.
                              peakbagger,

                              Can you post your adjustable tilt solutions? I am looking to do this on panels mounted on my pergola and side of the house facing southward. Single rows of 8-10 panels and adjusting one at a time is no problem.

                              I'm also wondering about birds too perching on the edge or if the tilt is too flat and making a mess on these. Any experience with this?

                              Comment

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