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<DIV><FONT face=Arial size=2>I was hesitant to reply because I surely will look
foolish, but perhaps it may help someone in the future. </FONT><FONT
face=Arial size=2>I did something very stupid back in 2001 that caused an
explosion. </FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2>The battery bank (12 volt, 660AH) was located in a
metal cargo container next to the wall and set in a plastic container. The
container had open doors on both ends. The battery was in the absorption cycle
with heavy gassing. I noticed that the positive terminal was slightly loose.
Fully aware of the danger of the task I was performing, I grabbed my socket
wrench and began to carefully snug it down. Even though I carefully observed the
location of the wrench, I did not think about the steel container wall as
having a path back to battery negative. It did. I blew the top off a battery
that I was standing over. Fortunately I was wearing safety glasses or I
probably would not be here today typing this. There was a water hydrant
near and I was able to flood my face and body for about 15 minutes. No
facial scares but a lessen very well learned: Do NOT work on batteries that
are off gassing. Gassing begins at about 2.3 volts per cell.
</FONT><FONT face=Arial size=2>If you are a battery novice, I encourage you to
thoroughly educate yourself and do not neglect your safety gear when working on
batteries.</FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2>Another event I witnessed: In 2007 I was at a
campground and heard an explosion. The owner of an RV a few spaces down from me
was opening the battery compartment as I walked up. Inside he had
un-vented batteries in the same compartment as the inverter and other switch
gear. His batteries were obviously gassing when something sparked it off. The
top was blown off a 6 volt battery and he had electrolyte everywhere and a
damaged cargo door. </FONT><FONT face=Arial size=2>We work on hundreds of RV's
and sadly I see this kind of poor "workmanship" every week at our
service center.</FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2>Larry Crutcher</FONT></DIV>
<DIV><FONT face=Arial size=2>Starlight Solar Power Systems</FONT></DIV>
<DIV><FONT face=Arial size=2>928-342-9103</FONT></DIV>
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<DIV style="FONT: 10pt arial">----- Original Message ----- </DIV>
<DIV
style="BACKGROUND: #e4e4e4; FONT: 10pt arial; font-color: black"><B>From:</B>
<A title=kent@coveoregon.com href="mailto:kent@coveoregon.com">Kent
Osterberg</A> </DIV>
<DIV style="FONT: 10pt arial"><B>To:</B> <A
title=re-wrenches@lists.re-wrenches.org
href="mailto:re-wrenches@lists.re-wrenches.org">RE-wrenches</A> </DIV>
<DIV style="FONT: 10pt arial"><B>Sent:</B> Wednesday, December 15, 2010 10:21
AM</DIV>
<DIV style="FONT: 10pt arial"><B>Subject:</B> Re: [RE-wrenches] Battery based
hydrogen incidents</DIV>
<DIV><BR></DIV>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 cite=mid:003601cb9c72$8db6bfc0$a9243f40$@com type="cite">
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<DIV class=WordSection1>
<P class=MsoNormal><SPAN
style="FONT-SIZE: 14pt; COLOR: windowtext; FONT-FAMILY: 'Century Gothic','sans-serif'">Ken
– <O:P></O:P></SPAN></P>
<P class=MsoNormal><SPAN
style="FONT-SIZE: 14pt; COLOR: windowtext; FONT-FAMILY: 'Century Gothic','sans-serif'"><O:P></O:P></SPAN></P>
<P class=MsoNormal><SPAN
style="FONT-SIZE: 14pt; COLOR: windowtext; FONT-FAMILY: 'Century Gothic','sans-serif'">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.<O:P></O:P></SPAN></P>
<P class=MsoNormal><SPAN
style="FONT-SIZE: 14pt; COLOR: windowtext; FONT-FAMILY: 'Century Gothic','sans-serif'"><O:P></O:P></SPAN></P>
<P class=MsoNormal><SPAN
style="FONT-SIZE: 14pt; COLOR: windowtext; FONT-FAMILY: 'Century Gothic','sans-serif'"><O:P></O:P></SPAN></P>
<P class=MsoNormal><SPAN
style="FONT-SIZE: 14pt; COLOR: windowtext; FONT-FAMILY: 'Century Gothic','sans-serif'">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.<O:P></O:P></SPAN></P>
<P class=MsoNormal><SPAN
style="FONT-SIZE: 14pt; COLOR: windowtext; FONT-FAMILY: 'Century Gothic','sans-serif'"><O:P></O:P></SPAN></P>
<P class=MsoNormal><SPAN
style="FONT-SIZE: 14pt; COLOR: windowtext; FONT-FAMILY: 'Century Gothic','sans-serif'">Q
- How many battery based hydrogen incidents have happened in our collective
experience?<O:P></O:P></SPAN></P>
<P class=MsoNormal><SPAN
style="FONT-SIZE: 14pt; COLOR: windowtext; FONT-FAMILY: 'Century Gothic','sans-serif'"><O:P></O:P></SPAN></P>
<P class=MsoNormal><SPAN
style="FONT-SIZE: 14pt; COLOR: windowtext; FONT-FAMILY: 'Century Gothic','sans-serif'"><O:P></O:P></SPAN></P>
<P class=MsoNormal><SPAN
style="FONT-SIZE: 14pt; COLOR: windowtext; FONT-FAMILY: 'Century Gothic','sans-serif'"><O:P></O:P></SPAN></P>
<DIV>
<P class=MsoNormal><SPAN
style="COLOR: windowtext; FONT-FAMILY: 'Century Gothic','sans-serif'">Dana
Orzel<O:P></O:P></SPAN></P>
<P class=MsoNormal><SPAN
style="COLOR: windowtext; FONT-FAMILY: 'Century Gothic','sans-serif'">Great
Solar Works, Inc<O:P></O:P></SPAN></P>
<P class=MsoNormal><SPAN
style="COLOR: windowtext; FONT-FAMILY: 'Century Gothic','sans-serif'">E - <A
class=moz-txt-link-abbreviated
href="mailto:dana@solarwork.com">dana@solarwork.com</A><O:P></O:P></SPAN></P>
<P class=MsoNormal><SPAN
style="COLOR: windowtext; FONT-FAMILY: 'Century Gothic','sans-serif'">V -
970.626.5253<O:P></O:P></SPAN></P>
<P class=MsoNormal><SPAN
style="COLOR: windowtext; FONT-FAMILY: 'Century Gothic','sans-serif'">F -
970.626.4140<O:P></O:P></SPAN></P>
<P class=MsoNormal><SPAN
style="COLOR: windowtext; FONT-FAMILY: 'Century Gothic','sans-serif'">C -
970.209.4076<O:P></O:P></SPAN></P>
<P class=MsoNormal><SPAN
style="COLOR: windowtext; FONT-FAMILY: 'Century Gothic','sans-serif'">web -
<A class=moz-txt-link-abbreviated
href="http://www.solarwork.com">www.solarwork.com</A><O:P></O:P></SPAN></P>
<P class=MsoNormal><SPAN
style="COLOR: windowtext; FONT-FAMILY: 'Century Gothic','sans-serif'"><O:P></O:P></SPAN></P>
<P class=MsoNormal><SPAN
style="COLOR: windowtext; FONT-FAMILY: 'Century Gothic','sans-serif'">"Responsible
Technologies for Responsible People since 1988"</SPAN><SPAN
style="FONT-SIZE: 11pt; COLOR: windowtext; FONT-FAMILY: 'Calibri','sans-serif'"><O:P></O:P></SPAN></P>
<P class=MsoNormal><SPAN
style="COLOR: windowtext; FONT-FAMILY: 'Century Gothic','sans-serif'">Do not
ever belive anything, but seriously trust through
action.<O:P></O:P></SPAN></P></DIV>
<P class=MsoNormal><SPAN
style="FONT-SIZE: 14pt; COLOR: windowtext; FONT-FAMILY: 'Century Gothic','sans-serif'"><O:P></O:P></SPAN></P>
<DIV>
<DIV
style="BORDER-RIGHT: medium none; PADDING-RIGHT: 0in; BORDER-TOP: rgb(181,196,223) 1pt solid; PADDING-LEFT: 0in; PADDING-BOTTOM: 0in; BORDER-LEFT: medium none; PADDING-TOP: 3pt; BORDER-BOTTOM: medium none">
<P class=MsoNormal style="MARGIN-LEFT: 0.5in"><B><SPAN
style="FONT-SIZE: 10pt; COLOR: windowtext; FONT-FAMILY: 'Tahoma','sans-serif'">From:</SPAN></B><SPAN
style="FONT-SIZE: 10pt; COLOR: windowtext; FONT-FAMILY: 'Tahoma','sans-serif'">
<A class=moz-txt-link-abbreviated
href="mailto:re-wrenches-bounces@lists.re-wrenches.org">re-wrenches-bounces@lists.re-wrenches.org</A>
[<A class=moz-txt-link-freetext
href="mailto: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<O:P></O:P></SPAN></P></DIV></DIV>
<P class=MsoNormal style="MARGIN-LEFT: 0.5in"><O:P></O:P></P>
<P class=MsoNormal style="MARGIN-LEFT: 0.5in">Fellow Wrenches,<BR><BR>The
discussion about battery venting reminds me of a useful and inexpensive
program, <A
href="http://pocketengineer.design.officelive.com/battery_ventilation.aspx"
moz-do-not-send="true">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<O:P></O:P></P></DIV><PRE wrap=""><HR width="90%" SIZE=4>
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