Bob<br><br>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!<br>
<br>Bill<br><br><div class="gmail_quote">On Tue, Jan 17, 2012 at 4:37 PM, <a href="mailto:boB@midnitesolar.com">boB@midnitesolar.com</a> <span dir="ltr"><<a href="mailto:boB@midnitesolar.com">boB@midnitesolar.com</a>></span> wrote:<br>
<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
<div bgcolor="#FFFFFF" text="#000000"><div class="im">
On 1/17/2012 4:18 PM, benn kilburn wrote:
<blockquote type="cite">
<div dir="ltr">
boB,
<div>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?</div>
<div>benn<br>
<br>
<span style="color:rgb(0,32,96)"><font face="'Franklin Gothic
Medium'">DayStar Renewable Energy Inc. </font></span>
<div>
<div><font face="'Franklin
Gothic Medium'"><a href="mailto:benn@daystarsolar.ca" target="_blank">benn@daystarsolar.ca</a></font></div>
<div><font face="'Franklin
Gothic Medium'"><a href="tel:780-906-7807" value="+17809067807" target="_blank">780-906-7807</a> </font></div>
<div><font face="'Franklin
Gothic Medium'">HAVE A SUNNY DAY
</font></div>
</div>
</div>
</div>
</blockquote>
<br>
<br>
<br></div>
No mods. However, as you can see, if the controller is maxed out as
far as<br>
array size, that could limit the snow melting effect. I don't have
any hard<br>
data as for the minimum power needed to apply to the array for snow
melting,<br>
but it could be around twice the power to melt snow as the power
rating of<br>
the array. Yesterday's experiment was less than 2wice the power
rating<br>
and it may have been fine with with even less, so that's a very good
sign.<br>
<br>
How much power does it take to melt snow off of a car's rear window
from<br>
the electric defroster ? It's a similar kind thing.<br>
<br>
Diodes ?? You mean the bypass diodes ?? No problem. Those don't<br>
conduct in this case.<span class="HOEnZb"><font color="#888888"><br>
<br>
boB</font></span><div><div class="h5"><br>
<br>
<br>
<br>
<blockquote type="cite">
<div dir="ltr">
<div>
<div>
<div><br>
</div>
</div>
<br>
<br>
<div>
<hr>Date: Mon, 16 Jan 2012 13:14:36 -0800<br>
From: <a href="mailto:boB@midnitesolar.com" target="_blank">boB@midnitesolar.com</a><br>
To: <a href="mailto:re-wrenches@lists.re-wrenches.org" target="_blank">re-wrenches@lists.re-wrenches.org</a><br>
Subject: Re: [RE-wrenches] Shedding ice<br>
<br>
On 1/16/2012 11:39 AM, David Katz wrote:
<blockquote>
<font style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1f497d">Mark,<br>
I believe the Midnite Classic has this feature built in.
Check with them.<br>
David Katz</font><br>
<br>
</blockquote>
<br>
<br>
It just snowed up here in Arlington, Washington A.C. and we
were just starting to melt some snow<br>
on a couple of modules on our roof just now with one of our
charge controllers here in the lab.<br>
<br>
This feature is not yet in the Classic, BUT, check out this
experiment that I did about 3 years ago<br>
in my front yard with an animated gif time lapse.<br>
<br>
One module is being powered and the other is not powered,
just sitting there for comparison.<br>
These are KC125s.<br>
<br>
The time involved here was about 3 hours and took about 1
kW-hour of energy but gives you<br>
an idea of what may be done with this idea. One thing not
in our favor here is that the module<br>
that is being powered is resting on the ground, in the snow,
which would significantly<br>
hinder snow melting I would think rather than being properly
mounted.<br>
<br>
Oh what fun it is to melt some PV snow tonight !<br>
<br>
<a href="http://fusion.midnitesolar.com/PVsnowMelt3.gif" target="_blank">http://fusion.midnitesolar.com/PVsnowMelt3.gif</a><br>
<br>
boB<br>
<br>
<br>
<br>
<br>
<br>
<br>
<br>
<br>
<blockquote>
<div>
<font style="font-size:10.0pt;font-family:"Tahoma","sans-serif""><b>From</b>:
Mark Dickson [<a href="mailto:Mark@OasisMontana.com" target="_blank">mailto:Mark@OasisMontana.com</a>]
<br>
<b>Sent</b>: Monday, January 16, 2012 10:00 AM<br>
<b>To</b>: 'RE-wrenches' <a href="mailto:re-wrenches@lists.re-wrenches.org" target="_blank"><re-wrenches@lists.re-wrenches.org></a>
<br>
<b>Subject</b>: [RE-wrenches] Shedding ice <br>
</font> <br>
</div>
<div>
<p><font face="Arial" color="navy"><span style="font-size:10.0pt;font-family:Arial;color:navy">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. . .</span></font></p>
<p><font face="Arial" color="navy"><span style="font-size:10.0pt;font-family:Arial;color:navy"> </span></font></p>
<div>
<p><font face="Comic
Sans MS" color="navy"><span style>Best regards,</span></font></p>
<p><font face="Comic
Sans MS" color="navy"><span style> </span></font></p>
<p><font face="Comic
Sans MS" color="navy"><span style>Mark Dickson,</span></font><font color="navy"><span style="color:navy"></span></font></p>
<p><font face="ArialMT" color="navy"><span style="font-size:10.0pt;font-family:ArialMT;color:navy">NABCEP
Certified Solar PV Installer ™</span></font></p>
<p><font face="Comic
Sans MS" color="navy"><span style>Oasis Montana Inc.</span></font></p>
</div>
<p><font face="Arial" color="navy"><span style="font-size:10.0pt;font-family:Arial;color:navy"> </span></font><br>
</p>
</div>
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<br></blockquote></div><br><br clear="all"><br>-- <br>Bill Hoffer PE<br>NABCEP Certified Solar PV Installer™<br>Sunergy Engineering Services PLLC<br>2504 Columbia Ave NW<br>East Wenatchee WA 98802-3941<br><a href="mailto:SunEngSer@gmail.com">SunEngSer@gmail.com</a> Cell:(509)679-6165<br>
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