<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN">
<HTML xmlns="http://www.w3.org/TR/REC-html40" xmlns:v =
"urn:schemas-microsoft-com:vml" xmlns:o =
"urn:schemas-microsoft-com:office:office" xmlns:w =
"urn:schemas-microsoft-com:office:word" xmlns:m =
"http://schemas.microsoft.com/office/2004/12/omml"><HEAD>
<META http-equiv=Content-Type content="text/html; charset=iso-8859-1">
<META content="MSHTML 6.00.6001.18639" name=GENERATOR>
<STYLE>@font-face {
font-family: Calibri;
}
@font-face {
font-family: Tahoma;
}
@font-face {
font-family: Consolas;
}
@page WordSection1 {size: 8.5in 11.0in; margin: 1.0in 1.0in 1.0in 1.0in; }
P.MsoNormal {
FONT-SIZE: 12pt; MARGIN: 0in 0in 0pt; FONT-FAMILY: "Times New Roman","serif"
}
LI.MsoNormal {
FONT-SIZE: 12pt; MARGIN: 0in 0in 0pt; FONT-FAMILY: "Times New Roman","serif"
}
DIV.MsoNormal {
FONT-SIZE: 12pt; MARGIN: 0in 0in 0pt; FONT-FAMILY: "Times New Roman","serif"
}
A:link {
COLOR: blue; TEXT-DECORATION: underline; mso-style-priority: 99
}
SPAN.MsoHyperlink {
COLOR: blue; TEXT-DECORATION: underline; mso-style-priority: 99
}
A:visited {
COLOR: purple; TEXT-DECORATION: underline; mso-style-priority: 99
}
SPAN.MsoHyperlinkFollowed {
COLOR: purple; TEXT-DECORATION: underline; mso-style-priority: 99
}
P.MsoPlainText {
FONT-SIZE: 10.5pt; MARGIN: 0in 0in 0pt; FONT-FAMILY: Consolas; mso-style-priority: 99; mso-style-link: "Plain Text Char"
}
LI.MsoPlainText {
FONT-SIZE: 10.5pt; MARGIN: 0in 0in 0pt; FONT-FAMILY: Consolas; mso-style-priority: 99; mso-style-link: "Plain Text Char"
}
DIV.MsoPlainText {
FONT-SIZE: 10.5pt; MARGIN: 0in 0in 0pt; FONT-FAMILY: Consolas; mso-style-priority: 99; mso-style-link: "Plain Text Char"
}
SPAN.EmailStyle17 {
COLOR: #1f497d; FONT-FAMILY: "Calibri","sans-serif"; mso-style-type: personal-reply
}
SPAN.PlainTextChar {
FONT-FAMILY: Consolas; mso-style-priority: 99; mso-style-link: "Plain Text"; mso-style-name: "Plain Text Char"
}
.MsoChpDefault {
mso-style-type: export-only
}
DIV.WordSection1 {
page: WordSection1
}
</STYLE>
<!--[if gte mso 9]><xml>
<o:shapedefaults v:ext="edit" spidmax="1026" />
</xml><![endif]--><!--[if gte mso 9]><xml>
<o:shapelayout v:ext="edit">
<o:idmap v:ext="edit" data="1" />
</o:shapelayout></xml><![endif]--></HEAD>
<BODY lang=EN-US vLink=purple link=blue bgColor=#ffffff>
<DIV>If budget allows, you might check out <A
href="http://www.atticbreeze.net">www.atticbreeze.net</A></DIV>
<DIV> </DIV>
<DIV>Check out the new controller - let's you set temp and humidity parameters
for operation.</DIV>
<DIV> </DIV>
<DIV>Holt E. Kelly<BR>Holtek Fireplace & Solar Products<BR>500 Jewell
Dr.<BR>Waco TX. 76712<BR>254-751-9111<BR><A
href="http://www.holteksolar.com">www.holteksolar.com</A><BR></DIV>
<BLOCKQUOTE
style="PADDING-RIGHT: 0px; PADDING-LEFT: 5px; MARGIN-LEFT: 5px; BORDER-LEFT: #000000 2px solid; MARGIN-RIGHT: 0px">
<DIV style="FONT: 10pt arial">----- Original Message ----- </DIV>
<DIV
style="BACKGROUND: #e4e4e4; FONT: 10pt arial; font-color: black"><B>From:</B>
<A title=bteitelbaum@aeesolar.com href="mailto:bteitelbaum@aeesolar.com">Brian
Teitelbaum</A> </DIV>
<DIV style="FONT: 10pt arial"><B>To:</B> <A
title=re-wrenches@lists.re-wrenches.org
href="mailto:re-wrenches@lists.re-wrenches.org">RE-wrenches</A> </DIV>
<DIV style="FONT: 10pt arial"><B>Sent:</B> Friday, January 20, 2012 4:01
PM</DIV>
<DIV style="FONT: 10pt arial"><B>Subject:</B> Re: [RE-wrenches] best way to
connect 12v fans directly to panels with a higher voltage?</DIV>
<DIV><BR></DIV>
<DIV class=WordSection1>
<P class=MsoPlainText>Hi James,<o:p></o:p></P>
<P class=MsoPlainText><o:p> </o:p></P>
<P class=MsoPlainText>I second Jay's SNAP-Fan recommendation. They are the
highest quality DC fans that I've seen. Here's their website:<o:p></o:p></P>
<P class=MsoPlainText><o:p> </o:p></P>
<P class=MsoPlainText><A
href="http://www.snap-fan.com/index.html">http://www.snap-fan.com/index.html</A><o:p></o:p></P>
<P class=MsoPlainText><o:p> </o:p></P>
<P class=MsoPlainText>You might be able to use those Grainer fans on direct
PV, but you will have to find out what the fan's motor specs are. Many "12VDC"
motors can't handle voltages above about 15VDC, making them unsuitable for
direct PV applications. If that is the case, you will have to add batteries
(and a charge controller) to the system. You will also need to control the
fans with a thermostat or timer; otherwise the fans will just run constantly
until the battery is drained. This adds cost and complexity to what could
otherwise be a very simple set-up.<o:p></o:p></P>
<P class=MsoPlainText><o:p> </o:p></P>
<P class=MsoPlainText>The motors on the SNAP-Fans are rated up to 40VDC, so
they can run PV-direct on 12V nominal (36-cell) or 24V nominal (72-cell)
modules. At 24VDC nominal (operating at about 35VDC) they will draw almost
three times the amperage (meaning 5-6 times the wattage), and develop almost
twice the RPM as they do on a 12V nominal module (operating at about 17.5VDC).
They will also move 2-3 times the CFM at 24V nominal as they do at 12V
nominal.<o:p></o:p></P>
<P class=MsoPlainText><o:p> </o:p></P>
<P class=MsoPlainText>You can also run the SNAP-Fans with 60-cell modules of
course, and that will likely be the cheapest way to go. The fans will operate
at around 30VDC on a typical 60-cell module. I’m not familiar with the ASW
modules, but as long as they have 72 or fewer cells, you’ll be fine with the
SNAP-Fans<o:p></o:p></P>
<P class=MsoPlainText><o:p> </o:p></P>
<P class=MsoPlainText>See the installation manual on the SNAP-Fan website for
some great operating charts, and how to wire multiple fans in series-parallel
arrangements with PV (you can wire two 12VDC fans in series and power them at
24V and the fans will run at their 12V speed). Unfortunately, the charts only
show performance at 12V, 18V, and 24V, and not at 30 or 35V, but I'll bet the
manufacturer has those figures too. <o:p></o:p></P>
<P class=MsoPlainText><o:p> </o:p></P>
<P class=MsoPlainText>Of course, the faster you run the fans, the shorter the
brush life will be, so take that into consideration.<o:p></o:p></P>
<P class=MsoPlainText><o:p> </o:p></P>
<P class=MsoPlainText>One more point about running motors PV-direct: the
larger the PV array is, the more hours per day the motor will run at full
speed. A motor that draws 100W, powered by a 100W module, will only run at
full speed at noon each day. However, a 200W module will develop 100W in half
the amount of sunlight, so the fan will run at full speed for many more hours
per day, and even on cloudy days. A 100W motor will draw only 100W even with a
1000W PV array, but will run at full speed in 10% sunlight (this is a little
oversimplified, as a 100W motor would barely load down a 1kW PV array, so the
motor will operate at a higher voltage, drawing more power).<o:p></o:p></P>
<P class=MsoPlainText><o:p> </o:p></P>
<P class=MsoPlainText>As far as “Code compliant” hookup, that should be
easy…or hard. I doubt that any of the DC fans are Listed, so that’s a problem
right there. Otherwise just use good wiring methods and you’ll be fine. If you
size the wire to 156% of the max PV amps, you don’t even need overcurrent
protection, although you should have a PV disconnect. I’d use a MidNite Big
Baby box and 150VDC breakers.<o:p></o:p></P>
<P class=MsoPlainText><o:p> </o:p></P>
<P class=MsoPlainText>Brian Teitelbaum<o:p></o:p></P>
<P class=MsoPlainText>AEE Solar<o:p></o:p></P>
<P class=MsoPlainText><o:p> </o:p></P>
<P
class=MsoPlainText>__________________________________________________________________________________________________________________
<o:p></o:p></P>
<P class=MsoNormal><SPAN
style="FONT-SIZE: 11pt; COLOR: #1f497d; FONT-FAMILY: 'Calibri','sans-serif'"><o:p> </o:p></SPAN></P>
<P class=MsoPlainText>> Hi James<o:p></o:p></P>
<P class=MsoPlainText><o:p> </o:p></P>
<P class=MsoPlainText><o:p> </o:p></P>
<P class=MsoPlainText>I suggest you use Snap Fans. These are DC fans. And
super efficient. They come in a few sizes/CFM rates.<o:p></o:p></P>
<P class=MsoPlainText><o:p> </o:p></P>
<P class=MsoPlainText><o:p> </o:p></P>
<P class=MsoPlainText><o:p> </o:p></P>
<P class=MsoPlainText>Check out Greenwired.net they carry them.
<o:p></o:p></P>
<P class=MsoPlainText><o:p> </o:p></P>
<P class=MsoPlainText>Jay<o:p></o:p></P>
<P class=MsoPlainText><o:p> </o:p></P>
<P class=MsoPlainText>Peltz Power<o:p></o:p></P>
<P class=MsoNormal><SPAN
style="FONT-SIZE: 11pt; COLOR: #1f497d; FONT-FAMILY: 'Calibri','sans-serif'"><o:p> </o:p></SPAN></P>
<DIV
style="BORDER-RIGHT: medium none; PADDING-RIGHT: 0in; BORDER-TOP: #b5c4df 1pt solid; PADDING-LEFT: 0in; PADDING-BOTTOM: 0in; BORDER-LEFT: medium none; PADDING-TOP: 3pt; BORDER-BOTTOM: medium none">
<P class=MsoNormal><B><SPAN
style="FONT-SIZE: 10pt; FONT-FAMILY: 'Tahoma','sans-serif'">From:</SPAN></B><SPAN
style="FONT-SIZE: 10pt; FONT-FAMILY: 'Tahoma','sans-serif'">
re-wrenches-bounces@lists.re-wrenches.org
[mailto:re-wrenches-bounces@lists.re-wrenches.org] <B>On Behalf Of </B>James
Rudolph<BR><B>Sent:</B> Friday, January 20, 2012 8:03 AM<BR><B>To:</B>
RE-wrenches<BR><B>Subject:</B> [RE-wrenches] best way to connect 12v fans
directly to panels with a higher voltage?<o:p></o:p></SPAN></P></DIV>
<P class=MsoNormal><o:p> </o:p></P>
<P class=MsoNormal style="MARGIN-BOTTOM: 12pt">Dearest Wrenchies,<BR><BR
clear=all><SPAN style="COLOR: black">So here is the situation, we have a
customer with a passively heated kiln for drying lumber. Basically it is a
greenhouse. There is no supplemental heat, or power at the site where it is.
When it begins to be heated moisture will be driven from the lumber, which
needs to be exhausted by fans. We need PV because there is no power there, and
because we want to be completely solar. Rather than set up a charger
controller and batteries, along with humidity controls for the fans, I thought
it would be simplest to get some panels and wire them directly to the fans.
That way, when the sun is shining and the kiln is being heated, the fans will
be on to exhaust the moisture, and when the sun is not they are off. With that
said the customer has alredy bought the 4,12v/18a fans from grainger and
has some ASW 240w 37V panels. I was wondering( since my work is always
grid-tie applications) what would be the best code compliant way to hook up
all this together.<BR>Many thanks in advance for the help.<BR><BR>Sunny
Regards,<BR><BR><BR></SPAN><B>James B Rudolph<BR>NABCEP Certified PV
Installer<BR>Certified Californian Journeyman<BR><BR></B><o:p></o:p></P></DIV>
<P>
<HR>
<P></P>_______________________________________________<BR>List sponsored by
Home Power magazine<BR><BR>List Address:
RE-wrenches@lists.re-wrenches.org<BR><BR>Options &
settings:<BR>http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org<BR><BR>List-Archive:
http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org<BR><BR>List
rules & etiquette:<BR>www.re-wrenches.org/etiquette.htm<BR><BR>Check out
participant
bios:<BR>www.members.re-wrenches.org<BR><BR></BLOCKQUOTE></BODY></HTML>