Pieter:
Interesting. One would think the Coast Guard would have access to the space lasers. These should easily melt off any snow accumulation. William Miller Miller Solar 17395 Oak Road, Atascadero, CA 93422 805-438-5600 www.millersolar.com CA Lic. 773985 *From:* RE-wrenches [mailto:re-wrenches-boun...@lists.re-wrenches.org] *On Behalf Of *pieter offgridenterprises.org via RE-wrenches *Sent:* Friday, December 6, 2024 11:56 AM *To:* RE-wrenches *Cc:* pieter offgridenterprises.org *Subject:* Re: [RE-wrenches] Panel installation in snow country 0.02 Howie, We have never tried active ice melting systems, but did have a client ( USCG) try various methods and ultimately gave up for a variety of reasons. Based on that hearsay evidence I would advise against attempting any sort of active Ice melting system. For what it is worth wind farm operators used to use Mop and Glo on turbine rotors to help shed Ice, dirt, and insect contamination and it resulted in noticeable improvement. I have not heard of anybody trying that on Solar, but it would be an easy cheap experiment to treat one or two panels in an array to get a comparison. Pieter Huebner Project Manager Off Grid Enterprises *From:* RE-wrenches <re-wrenches-boun...@lists.re-wrenches.org> *On Behalf Of *Howie Michaelson via RE-wrenches *Sent:* Friday, December 6, 2024 1:30 PM *To:* RE-wrenches <re-wrenches@lists.re-wrenches.org> *Cc:* Howie Michaelson <howie.michael...@gmail.com> *Subject:* Re: [RE-wrenches] Panel installation in snow country 0.02 I always love how what I imagine to be a simple question often sparks a much wider, interesting conversation on this list. In this instance, I am dealing with an off- grid client in a colder, snowier, cloudier section of Vermont, but not an extreme environment. The panels are mounted on a fixed, 35 degree rack. The client is asking if putting heat pans behind the panels would be ok and useful for dealing with sticky snow/ice scenarios. Having never looked into the option, assuming it was probably a bad idea, I told him as much. But, of course he found an internet site that advertises such things specifically for solar panels. I was fairly skeptical, but since I really had never truly vetted the idea, I figured I would asked all you esteemed colleagues if anyone had any direct experience or knowledge of such things. So that is what I'm wondering about. Has anyone here had any direct, indirect or hearsay knowledge about devices for melting some amount of snow or ice build up off of panels? I'm not thinking this would be the primary method of clearing them, only a way to help get a sticky layer to release. I imagine it would be controlled by a simple on/off switch that the owner deals with as he deemed necessary. I am happy to hear everyone's stories about design, methodology, or recommendations for dealing with snow, since this is an ongoing concern in this part of the world (and hopefully will continue to be), but at the moment I am most interested to get feedback about methods of melting snow. Thanks as always, Howie Sun Catcher On Fri, Dec 6, 2024, 1:52 PM Dana Orzel via RE-wrenches < re-wrenches@lists.re-wrenches.org> wrote: Having installed at up to 13,200’ elevation (60° rack mount) and in snow country for most of most of 37 years and dealing with installations by others that almost or completely come off the roof here is my 0.02: Low angle roofs less than 35deg seem to take on most of the damage incidents. Avalanches are most prevalent at 32-35+deg. Avys tend not to slide at less than 32 deg. Is the lower edge of the array shaded or partial shade on part of the array with the low angle winter sun? This allows for ice up on the bottom edge or on a section of the array. Is there a drop zone for the snow? I use 5’ min below the leading edge for a mountain install I would increase this to higher. I know this sounds obvious - Is there a snow fence or obstruction (door shed roof) below the array? I now install esp. on lower angle roofs a mid-third rail & use 50% more contact to the roof points (cheap array life insurance). If using a micro inverter or optimizer – attach this to the panel so it flexes with the panel if necessary not the rail mount system. Watch out for bolts that stick up close to the back sheet. Happy Hollar Daze all! _________________________________________________________ Dana Orzel GREAT SOLAR WORKS! C – 208.721.7003 E – d...@solarwork.com W - www. greatsolarworks.com www.solarwork.com *“Responsible Technologies for Responsible People since 1988!”* ---------- Forwarded message ---------- From: jay pozner via RE-wrenches <re-wrenches@lists.re-wrenches.org> To: RE-wrenches <re-wrenches@lists.re-wrenches.org> Cc: jay pozner <j...@outpostreconcepts.com> Bcc: Date: Fri, 6 Dec 2024 17:39:42 +0000 Subject: Re: [RE-wrenches] De-icing panels off grid I have gone around this many times on this one. It's interesting to hear all the perspectives of peers whom I greatly respect. In revisiting this I think context is really important. There are so many factors that can add up to "tip" the scales to favor this idea that one professional might or might not consider. I have seen a fair amount of destruction of PV from snow, and of course the disruption in PV performance which could then of course cascade to battery destruction. In trying to avoid the heat idea, I have made a secondary (small) array mounted vertically on a wall of a cabin to simply maintain a trickle charge of the batteries of the system during winter months when the cabin isn't being used, in efforts to keep the lead acid batteries topped off. Of course it's not perfect if the snow water content is high, and there is wind, but in an inter-mountain (dry) snowpack it seems to perform well. One idea that I am tilting towards more and more in these unique circumstances is to power the heat source (heat tape, etc) with the generator circuit. Of course there needs to be a reasonable sized generator on site, but for most of my stand alone situations this is more rule than exception. We can get fancy with a timer (to keep track of daylight hours) and a photosensor to automatically determine if the array is substantially covered, but truthfully I bet a simple switch used in these situations actuated by the system owner might suffice... Jay Pozner (970) 209-0024 On Fri, Dec 6, 2024 at 9:27 AM Todd Cory via RE-wrenches < re-wrenches@lists.re-wrenches.org> wrote: Yes, in deep snow country tall pole mounts can be expensive... especially with enough room below so the sliding snow never meets the bottom edge of the array. My home system has 5 pole mounts with the bottom edges ~6' above the ground. Now that engineering is mandated, this adds more expense to ensure sure the foundation can support the mechanical forces of this configuration. But shallow angle roof mounts risk having the bottom edge of the modules get ripped off (see attached picture) so here in the Mount Shasta area, this is the only thing that works. There was a thread where people were experimenting with reverse biasing modules to cause them to generate heat. I think boB was working on some kind of possibility for a charge controller option to do this, but I am not sure where that went. Todd On Thursday, December 5, 2024 5:49pm, "Howie Michaelson via RE-wrenches" < re-wrenches@lists.re-wrenches.org> said: Todd, In general that had been my philosophy, but sometimes pole mounts are just logistically to difficult/ expensive - especially large ones. In general, if it is a windy location, the snow doesn't stick around that long. However, even pole mounts at a steep angle can get encrusted and if it doesn't get warm enough or sunny, that can stick on the panels for a week or more. I've never considered anything like heat panels or tape, but if there is something that works that doesn't harm the panels, then it might be a decent option in some cases. Howie On Thu, Dec 5, 2024, 5:15 PM Todd Cory via RE-wrenches < re-wrenches@lists.re-wrenches.org> wrote: Passive works best. In big snow country here, I learned the hard way to only do pole mounts... and set the angle steep in the winter. The snow slides off and all is fine. Todd On Thursday, December 5, 2024 1:01pm, "Kirk Herander via RE-wrenches" < re-wrenches@lists.re-wrenches.org> said: https://glasscareexperts.com/solar-glass-protection/ I’ve never tried it but just heard about these people. From the bio they are the original makers of rain X, but they customized a product, several of them, to clean Pv panels and they also mentioned it can help to shed rain and snow. By the way, Rainx is not approved for such an application. *Kirk Herander / kirkh@vermont.solar <kirkh@vermont.solar>* *Owner|Principal, VT Solar, LLC* *Celebrating our 33st Anniversary 1991-2024!!* dba Vermont Solar Engineering 802.559.1225 On Thu, Dec 5, 2024 at 2:19 PM Howie Michaelson via RE-wrenches < re-wrenches@lists.re-wrenches.org> wrote: Has anyone successfully used heat panels or cables to melt iced-over panels (ie. without damaging the panels)? In heavy snow country, or over periods of freeze/thaw when pelty slushy snow sticks and freezes to panels, it would be nice to have a safe method of clearing them, especially off-grid. I remember discussions of the futility of backfeeding panels to heat them up to accomplish the same, but not about heat tape or pans that might be worth trying. Thanks, Howie Michaelson Sun Catcher _______________________________________________ List sponsored by Redwood Alliance Pay optional member dues here: http://re-wrenches.org List Address: RE-wrenches@lists.re-wrenches.org Change listserver email address & settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org There are two list archives for searching. 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