<div dir="auto">Put the fan at the intake near floor level and a passive vent at the ceiling <div dir="auto"><br></div><div dir="auto"><br></div></div><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">re-wrenches@lists.re-wrenches.org</a>> wrote:<br></div><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><u></u>

  
    
  
  <div>
    <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">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>
      <fieldset></fieldset>
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