Bob Wonder how Module manufacturer warranties will handle applying reverse current to the module , especially if it is more than the power rating of the module??? I would want that one in writing before risking having to write off an array in order to melt a little snow!
Bill On Tue, Jan 17, 2012 at 4:37 PM, b...@midnitesolar.com <b...@midnitesolar.com>wrote: > On 1/17/2012 4:18 PM, benn kilburn wrote: > > boB, > If this concept were to become a working option for the Classic, would the > modules have to be modified in any way? Why are the diodes not blocking > the reverse current? > benn > > DayStar Renewable Energy Inc. > b...@daystarsolar.ca > 780-906-7807 > HAVE A SUNNY DAY > > > > > No mods. However, as you can see, if the controller is maxed out as far as > array size, that could limit the snow melting effect. I don't have any > hard > data as for the minimum power needed to apply to the array for snow > melting, > but it could be around twice the power to melt snow as the power rating of > the array. Yesterday's experiment was less than 2wice the power rating > and it may have been fine with with even less, so that's a very good sign. > > How much power does it take to melt snow off of a car's rear window from > the electric defroster ? It's a similar kind thing. > > Diodes ?? You mean the bypass diodes ?? No problem. Those don't > conduct in this case. > > boB > > > > > > > > ------------------------------ > Date: Mon, 16 Jan 2012 13:14:36 -0800 > From: b...@midnitesolar.com > To: re-wrenches@lists.re-wrenches.org > Subject: Re: [RE-wrenches] Shedding ice > > On 1/16/2012 11:39 AM, David Katz wrote: > > Mark, > I believe the Midnite Classic has this feature built in. Check with them. > David Katz > > > > > It just snowed up here in Arlington, Washington A.C. and we were just > starting to melt some snow > on a couple of modules on our roof just now with one of our charge > controllers here in the lab. > > This feature is not yet in the Classic, BUT, check out this experiment > that I did about 3 years ago > in my front yard with an animated gif time lapse. > > One module is being powered and the other is not powered, just sitting > there for comparison. > These are KC125s. > > The time involved here was about 3 hours and took about 1 kW-hour of > energy but gives you > an idea of what may be done with this idea. One thing not in our favor > here is that the module > that is being powered is resting on the ground, in the snow, which would > significantly > hinder snow melting I would think rather than being properly mounted. > > Oh what fun it is to melt some PV snow tonight ! > > http://fusion.midnitesolar.com/PVsnowMelt3.gif > > boB > > > > > > > > > *From*: Mark Dickson [mailto:m...@oasismontana.com<m...@oasismontana.com>] > > *Sent*: Monday, January 16, 2012 10:00 AM > *To*: 'RE-wrenches' > <re-wrenches@lists.re-wrenches.org><re-wrenches@lists.re-wrenches.org> > *Subject*: [RE-wrenches] Shedding ice > > > I recall a conversation a while back about the possibility of “reversing” > the current in a solar module to increase the cell temp enough to shed > ice/rime. To follow-up, has anybody been successful at this? I am > guessing, if so, it would entail, removal of diodes, increasing PV and > battery capacity and some way to sense the ice at the very least. . . It > sounds good in theory, but I am skeptical as to whether it will work in > reality. . . > > > > Best regards, > > > > Mark Dickson, > > NABCEP Certified Solar PV Installer ™ > > Oasis Montana Inc. > > > > > > _______________________________________________ List sponsored by Home > Power magazine List Address: RE-wrenches@lists.re-wrenches.org Options & > settings: > http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.orgList-Archive: > http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List > rules & etiquette: www.re-wrenches.org/etiquette.htm Check out > participant bios: www.members.re-wrenches.org > > > _______________________________________________ > List sponsored by Home Power magazine > > List Address: RE-wrenches@lists.re-wrenches.org > > Options & > settings:http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org > > List-Archive: > http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org > > List rules & etiquette:www.re-wrenches.org/etiquette.htm > > Check out participant bios:www.members.re-wrenches.org > > > > _______________________________________________ > List sponsored by Home Power magazine > > List Address: RE-wrenches@lists.re-wrenches.org > > Options & settings: > http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org > > List-Archive: > http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org > > List rules & etiquette: > www.re-wrenches.org/etiquette.htm > > Check out participant bios: > www.members.re-wrenches.org > > > -- Bill Hoffer PE NABCEP Certified Solar PV Installer™ Sunergy Engineering Services PLLC 2504 Columbia Ave NW East Wenatchee WA 98802-3941 suneng...@gmail.com Cell:(509)679-6165
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