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<p>Putting the fan on the intake causes the battery box to be at
higher pressure. You don't want the pressure in the battery box
to be higher than the surrounding room, or it will push the H2S
into the room through any cracks. You want to create a vacuum
(lower pressure) in the battery box, so that the H2S is less
likely to enter the room, and is drawn out. That's why we always
put the fan on the exhaust side. <br>
</p>
<p>Ray Walters<br>
Remote Solar<br>
</p>
<div class="moz-cite-prefix">On 5/6/2025 1:20 PM, Bradley Bassett
wrote:<br>
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cite="mid:CAEpjgH2J3KvzBzbvDa7A9r2gU5KgEh2GdyJghUJBJ0xdgsQE+Q@mail.gmail.com">
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<div dir="auto">Put the fan at the intake near floor level and a
passive vent at the ceiling
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<br>
<div class="gmail_quote gmail_quote_container">
<div dir="ltr" class="gmail_attr">On Tue, May 6, 2025, 12:09 PM
Ray Walters via RE-wrenches <<a
href="mailto:re-wrenches@lists.re-wrenches.org"
moz-do-not-send="true" class="moz-txt-link-freetext">re-wrenches@lists.re-wrenches.org</a>>
wrote:<br>
</div>
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style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
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<p>Hi William;</p>
<p>Poor ventilation could be part of it, but I've also seen
corrosion problems from:<br>
clients over filling the cells, <br>
EQing to often, <br>
absorption voltage set too high and for too long, <br>
too high a charge rate, (too large an array)<br>
too high a temperature, due to floor heating and/or
insulated battery box. <br>
</p>
<p>my best systems seem to be on the lower side of array
size relative to battery size, with batteries in a
basement or garage that stays above freezing, but below
60F most of the year. <br>
</p>
<p>Sorry I don't have a line on explosion proof fans, but I
have a client with a 120 vac radon blower for the battery
exhaust that seems to do much better than the traditional
DC battery fans. (Not my install.)</p>
<p> I've only seen batteries blow twice:<br>
1) Idiot was arc welding next to a HUP battery and
multiple large sparks went right on to a cap; result: blew
the top off the cell. He had been told to construct a
battery enclosure around the batteries, but never did. <br>
2) a loose connection at a battery terminal arced, melted
the lead until the molten lead melted through the top of
the case and ignited the hydrogen, result: burned a clear
flame for a few seconds and went out without any major
damage. <br>
</p>
<p>So my take away is that unless the ignition source is in
the cell or within an inch of the cap, the hydrogen is too
low a concentration to ignite. Actually, are lead acid
battery internal plates and their external connections
considered "explosion proof"? <br>
</p>
<p>Ray Walters<br>
Remote Solar<br>
</p>
<p><br>
</p>
<div>On 5/6/2025 12:20 PM, William Miller via RE-wrenches
wrote:<br>
</div>
<blockquote type="cite">
<div>
<p class="MsoNormal"><span
style="font-size:12.0pt;font-family:"Verdana","sans-serif"">Friends:</span></p>
<p class="MsoNormal"><span
style="font-size:12.0pt;font-family:"Verdana","sans-serif""> </span></p>
<p class="MsoNormal"><span
style="font-size:12.0pt;font-family:"Verdana","sans-serif"">I
have two flooded battery arrays that have steel
cases that are corroding. I am sure poor
ventilation is the issue even though we have passive
vents high and low. I think I need active
ventilation. </span></p>
<p class="MsoNormal"><span
style="font-size:12.0pt;font-family:"Verdana","sans-serif""> </span></p>
<p class="MsoNormal"><span
style="font-size:12.0pt;font-family:"Verdana","sans-serif"">Does
anyone have knowledge of a 120VAC explosion proof
ceiling mounted exhaust fan?</span></p>
<p class="MsoNormal"><span
style="font-size:12.0pt;font-family:"Verdana","sans-serif""> </span></p>
<p class="MsoNormal"><span
style="font-size:12.0pt;font-family:"Verdana","sans-serif"">Thanks
in advance.</span></p>
<p class="MsoNormal"><span
style="font-size:12.0pt;font-family:"Verdana","sans-serif""> </span></p>
<p class="MsoNormal"><span
style="font-size:12.0pt;font-family:"Verdana","sans-serif"">William</span></p>
<p class="MsoNormal"><span
style="font-size:12.0pt;font-family:"Verdana","sans-serif""> </span></p>
<p class="MsoNormal"><span
style="font-size:12.0pt;font-family:"Arial","sans-serif"">Miller
Solar</span></p>
<p class="MsoNormal"><span
style="font-size:12.0pt;font-family:"Arial","sans-serif"">17395
Oak Road, Atascadero, CA 93422</span></p>
<p class="MsoNormal"><span
style="font-size:12.0pt;font-family:"Arial","sans-serif"">805-438-5600</span></p>
<p class="MsoNormal"><span
style="font-size:12.0pt;font-family:"Arial","sans-serif""><a
href="http://www.millersolar.com/" target="_blank"
rel="noreferrer" moz-do-not-send="true">www.millersolar.com</a></span></p>
<p class="MsoNormal"><span
style="font-size:12.0pt;font-family:"Arial","sans-serif"">CA
Lic. 773985</span></p>
<p class="MsoNormal"> </p>
<p class="MsoNormal"> </p>
</div>
<br>
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