38+ years in RE. Knowledge of one incident (an off-grid friend). Very sunny day. Very windy. My friend had both PV and a wind generator (still does). He had just stepped out of the room where the batteries were located when (as he described it) he heard something like a loud gunshot. He went back inside to find one of the L16s exploded, top completely blown off, and case broken much of the way down one side.
Had the incident occurred only minutes earlier, injuries could have resulted. He has since relocated his batteries to a dedicated (and vented) battery space. Dan --- On Wed, 12/15/10, Kent Osterberg <k...@coveoregon.com> wrote: From: Kent Osterberg <k...@coveoregon.com> Subject: Re: [RE-wrenches] Battery based hydrogen incidents To: "RE-wrenches" <re-wrenches@lists.re-wrenches.org> Date: Wednesday, December 15, 2010, 11:21 AM 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
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