Re: [RE-wrenches] Battery based hydrogen incidents

[Kent Osterberg]

Sounds like, in general, that the off-grid industry has been fortunate to not have hydrogen explosions.  That's good.  No explosions here either.  But one shouldn't take that as evidence that it couldn't happen.  I don't believe this is a circumstance where it is better to be lucky than good.  That's why I recommend doing the calculations. Kent Osterberg Blue Mountain Solar Dana wrote: Ken –   To meet the flow have run 2 and 3 fans to meet the flow. 2” output from the fan into a 4” header with a matching 2.5” inlet as far away on the lowest portion of the battery box.     In 22+ years in off grid installations I have yet to see or even hear of one hydrogen explosion. I get repeatedly asked why we have to go to the efforts we go to for box and venting. I am not able to provide even one incident that I have heard rumor of.   Q - How many battery based hydrogen incidents have happened in our collective experience?       Dana Orzel Great Solar Works, Inc E - d...@solarwork.com V - 970.626.5253 F - 970.626.4140 C - 970.209.4076 web - www.solarwork.com   "Responsible Technologies for Responsible People since 1988" Do not ever belive anything, but seriously trust through action.   From: re-wrenches-boun...@lists.re-wrenches.org [mailto:re-wrenches-boun...@lists.re-wrenches.org] On Behalf Of Kent Osterberg Sent: Tuesday, December 14, 2010 12:07 PM To: Wrenches Subject: [RE-wrenches] Battery Venting   Fellow Wrenches, The discussion about battery venting reminds me of a useful and inexpensive program, BattMV, for determining ventilation requirements per EN-50272.  EN-50272 is a European standard used to determine how much air flow is needed for a room, I don't know of a equivalent standard used in the U.S.  It takes a surprising amount of ventilation.  For a 400-AH 48-volt L16 bank charged at 57.6 volts and 24 amps, it's about 7 CFM just to keep the %H2 down to 4%.  A 12-volt Zephyr vent is good for about 5 CFM!   If you think you are venting enough, take some time and study this issue. Kent Osterberg Blue Mountain Solar _______________________________________________ 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

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