<html><head></head><body style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space; ">Hi Dan,<div><br></div><div>I've see this as well, but I don't put it down to a enclosure problem but a build up inside a individual battery cell,( plugged cap, etc) which IMHO even if the batteries were outside wouldn't help prevent it.</div><div>Never the less, why I use eye protection every time I go see batteries.</div><div><br></div><div><br></div><div><br></div><div>Jay</div><div><br></div><div>peltz power</div><div><br></div><div><br><div><div>On Dec 15, 2010, at 9:56 AM, Exeltech wrote:</div><br class="Apple-interchange-newline"><blockquote type="cite"><table cellspacing="0" cellpadding="0" border="0"><tbody><tr><td valign="top" style="font: inherit;">38+ years in RE. Knowledge of one incident (an off-grid friend).<br><br>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.<br><br>Had the incident occurred only minutes earlier, injuries could have resulted. He has since relocated his batteries to a dedicated (and vented) battery space.<br><br>Dan<br><br><br>--- On <b>Wed, 12/15/10, Kent Osterberg <i><<a href="mailto:kent@coveoregon.com">kent@coveoregon.com</a>></i></b> wrote:<br><blockquote style="border-left: 2px solid rgb(16, 16, 255); margin-left: 5px; padding-left: 5px;"><br>From: Kent Osterberg
<<a href="mailto:kent@coveoregon.com">kent@coveoregon.com</a>><br>Subject: Re: [RE-wrenches] Battery based hydrogen incidents<br>To: "RE-wrenches" <<a href="mailto:re-wrenches@lists.re-wrenches.org">re-wrenches@lists.re-wrenches.org</a>><br>Date: Wednesday, December 15, 2010, 11:21 AM<br><br><div id="yiv1034715313">
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.<br>
<br>
Kent Osterberg<br>
Blue Mountain Solar<br>
<br>
<br>
<br>
Dana wrote:
<blockquote type="cite">
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<div class="yiv1034715313WordSection1"><p class="yiv1034715313MsoNormal"><span style="font-size: 14pt; color: windowtext;">Ken
– </span></p><p class="yiv1034715313MsoNormal"><span style="font-size: 14pt; color: windowtext;"><br> </span></p><p class="yiv1034715313MsoNormal"><span style="font-size: 14pt; color: windowtext;">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.</span></p><div><span style="font-size: 14pt; color: windowtext;"> </span><br class="webkit-block-placeholder"></div><div><span style="font-size: 14pt; color: windowtext;"> </span><br class="webkit-block-placeholder"></div><p class="yiv1034715313MsoNormal"><span style="font-size: 14pt; color: windowtext;">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.</span></p><div><span style="font-size: 14pt; color: windowtext;"> </span><br class="webkit-block-placeholder"></div><p class="yiv1034715313MsoNormal"><span style="font-size: 14pt; color: windowtext;">Q
- How many battery based hydrogen incidents have happened in our
collective experience?</span></p><div><span style="font-size: 14pt; color: windowtext;"> </span><br class="webkit-block-placeholder"></div><p class="yiv1034715313MsoNormal"><span style="font-size: 14pt; color: windowtext;"><br></span></p>
<div><p class="yiv1034715313MsoNormal"><span style="color: windowtext;">Dana
Orzel</span></p><p class="yiv1034715313MsoNormal"><span style="color: windowtext;">Great
Solar Works, Inc</span></p><p class="yiv1034715313MsoNormal"><span style="color: windowtext;">E
- <a rel="nofollow" class="yiv1034715313moz-txt-link-abbreviated" ymailto="mailto:dana@solarwork.com" target="_blank" href="x-msg://1192/mc/compose?to=dana@solarwork.com">dana@solarwork.com</a></span></p><p class="yiv1034715313MsoNormal"><span style="color: windowtext;">V
- 970.626.5253</span></p><p class="yiv1034715313MsoNormal"><span style="color: windowtext;">F
- 970.626.4140</span></p><p class="yiv1034715313MsoNormal"><span style="color: windowtext;">C
- 970.209.4076</span></p><p class="yiv1034715313MsoNormal"><span style="color: windowtext;">web
- <a rel="nofollow" class="yiv1034715313moz-txt-link-abbreviated" target="_blank" href="http://www.solarwork.com/">www.solarwork.com</a></span></p><div><span style="color: windowtext;"> </span><br class="webkit-block-placeholder"></div><p class="yiv1034715313MsoNormal"><span style="color: windowtext;">"Responsible
Technologies for Responsible People since 1988"</span><span style="font-size: 11pt; color: windowtext;"></span></p><p class="yiv1034715313MsoNormal"><span style="color: windowtext;">Do
not ever belive anything, but seriously trust through action.</span></p>
</div><div><span style="font-size: 14pt; color: windowtext;"> </span><br class="webkit-block-placeholder"></div>
<div>
<div style="border-style: solid none none; border-color: rgb(181, 196, 223); border-width: 1pt medium medium; padding: 3pt 0in 0in;"><p class="yiv1034715313MsoNormal" style="margin-left: 0.5in;"><b><span style="font-size: 10pt; color: windowtext;">From:</span></b><span style="font-size: 10pt; color: windowtext;">
<a rel="nofollow" class="yiv1034715313moz-txt-link-abbreviated" ymailto="mailto:re-wrenches-bounces@lists.re-wrenches.org" target="_blank" href="x-msg://1192/mc/compose?to=re-wrenches-bounces@lists.re-wrenches.org">re-wrenches-bounces@lists.re-wrenches.org</a>
[<a rel="nofollow" class="yiv1034715313moz-txt-link-freetext" ymailto="mailto:re-wrenches-bounces@lists.re-wrenches.org" target="_blank" href="x-msg://1192/mc/compose?to=re-wrenches-bounces@lists.re-wrenches.org">mailto:re-wrenches-bounces@lists.re-wrenches.org</a>] <b>On Behalf Of </b>Kent
Osterberg<br>
<b>Sent:</b> Tuesday, December 14, 2010 12:07 PM<br>
<b>To:</b> Wrenches<br>
<b>Subject:</b> [RE-wrenches] Battery Venting</span></p>
</div>
</div><div style="margin-left: 0.5in; "> <br class="webkit-block-placeholder"></div><p class="yiv1034715313MsoNormal" style="margin-left: 0.5in;">Fellow Wrenches,<br>
<br>
The discussion about battery venting reminds me of a useful and
inexpensive program, <a rel="nofollow" target="_blank" href="http://pocketengineer.design.officelive.com/battery_ventilation.aspx">BattMV</a>,
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.<br>
<br>
Kent Osterberg<br>
Blue Mountain Solar</p>
</div>
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