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<DIV><FONT face=Arial size=2>The room has adequate passive ventilation. The roof
vent is needed just to actively increase the air flow. The
Solatube vent should do the job unless someone can suggest something
better.Thank you all for your help.</FONT></DIV>
<DIV><FONT face=Arial size=2>Best regards,</FONT></DIV>
<DIV><FONT face=Arial size=2>Joel Davidson</FONT></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=kent@coveoregon.com href="mailto:kent@coveoregon.com">Kent
Osterberg</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> Wednesday, April 08, 2009 12:59
PM</DIV>
<DIV style="FONT: 10pt arial"><B>Subject:</B> Re: [RE-wrenches] Solar vent for
flat roof</DIV>
<DIV><BR></DIV>Allan,<BR><BR>I recently studied this battery room venting
issue when an inspector challenged me to show that a Zephyr vent was adequate
to vent a room with a 48-volt 1700-amphour battery bank. I ended
up finding that to keep the hydrogen concentration down to 1% (1/4 the
explosive limit) required 75 CFM. The Zephyr vent at 5 CFM wasn't
anywhere near sufficient; we ended up putting in a 100 CFM vent fan that is
activated when the battery voltage exceeds 2.4 volts/cell.<BR><BR>Using a
solar vent fan is probably a good solution as long as the only charging source
is solar. If there are any other charging sources, a solar vent fan
wouldn't be adequate. <BR><BR>Kent Osterberg<BR>Blue Mountain
Solar<BR><BR> <BR><BR>Allan Sindelar wrote:
<BLOCKQUOTE cite=mid:013d01c9b868$c6bb19f0$7000a8c0@pelapallan type="cite"><PRE wrap="">We have twice used pairs of Zephyr Power Vents to successfully vent large
banks, up to around 2200A/hr @48V. A 12V unit exits roof or wall with a 2"
pvc stack; 48V is 3"; thus they flash just like standard plumbing vents.
Note that the charge rate is more important than battery capacity, as it
determines the amount of gassing that must be exhausted.
Allan at Positive Energy
-----Original Message-----
Wrenches,
Our client has 48 IBE 85N-15 batteries in a room with a flat roof. What is
your recommendation for a solar powered vent that works well and flashes
well so that it does not leak? Thanks in advance for your advice.
Joel Davidson
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