Re: [RE-wrenches] Solar vent for flat roof

[Kent Osterberg]

Dana, While the manufacturer of the Zephyr vent claims that it is explosion safe, it isn't a UL listed product and I seriously doubt that it would pass any listing agency's requirements.  Having had no explosions is a great result.  But don't fool yourself, a  pair of Zephyr vent fans cannot possibly provide sufficient ventilation to keep a battery room (or even a battery box) with a 2000-amphour 48-volt battery below the explosive limit.  It's fortunate that hydrogen, given half a chance, will dissipate quickly. When we removed the Zephyr vent and modified the venting for the battery room, we provided positive pressure to the room with the vent fan outside the room.  This avoided the issue of using a vent fan rated for explosive environments.  The ceiling vent is completely passive. Kent Osterberg Blue Mountain Solar Dana wrote: Kent –   Is your solar vent fan rated for the potential of explosive gasses and will the solar fan be working at full charge when the backup generator is running [if you have one]?   I have used 2 of the Zephyr fans on 2,000 ahr at 48 VDC battery banks and they are rated for the gasses,  and gotten great results.     Dana Orzel   Great Solar Works, Inc www.solarwork.com E - d...@solarwork.com V - 970.626.5253 F - 970.626.4140 C - 970.209.4076 “I'd put my money on solar energy… I hope we don't have to wait 'til oil and coal run out before we tackle that.” —Thomas Edison, in conversation with Henry Ford and Harvey Firestone, March 1931   From: re-wrenches-boun...@lists.re-wrenches.org [mailto:re-wrenches-boun...@lists.re-wrenches.org] On Behalf Of Kent Osterberg Sent: Wednesday, April 08, 2009 1:59 PM To: RE-wrenches Subject: Re: [RE-wrenches] Solar vent for flat roof   Allan, 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. 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. Kent Osterberg Blue Mountain Solar   Allan Sindelar wrote: 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   _______________________________________________ List sponsored by Home Power magazine   List Address: RE-wrenches@lists.re-wrenches.org   Options & settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org   List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org   List rules & etiquette: www.re-wrenches.org/etiquette.htm   Check out participant bios: www.members.re-wrenches.org           No virus found in this incoming message. Checked by AVG - www.avg.com Version: 8.0.238 / Virus Database: 270.11.45/2045 - Release Date: 04/07/09 06:41:00     _______________________________________________ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org Options & settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules & etiquette: www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.org No virus found in this incoming message. Checked by AVG - www.avg.com Version: 8.0.238 / Virus Database: 270.11.47/2047 - Release Date: 04/08/09 05:53:00

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