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<DIV><FONT size=2 face=Arial>I have sold thousands of off-grid PV systems
and hundreds of on-grid PV systems with batteries. In 1984,
one customer located 30 miles north of New Orleans with an
off-grid PV system and T-105 batteries reported that a battery
exploded. The cause was a clogged cell cap vent that trapped H2
that was ignited by transient current from a nearby lightning strike
(that also destroyed his charge controller). About 6 months later another nearby
lightning strike fried another controller. The PV array was a few hundred
feet from the home. The owner wired the PV array and home
equipment ground rods together and made sure that cap vent holes were kept
clean. Subsequent lightning storms caused no problems.</FONT></DIV>
<DIV><FONT size=2 face=Arial></FONT> </DIV>
<DIV><FONT size=2 face=Arial>The only exploded battery that I actually
saw was also in the 1980s at a Sears service station. An automobile
battery had exploded and tore a hole in the car engine hood.</FONT></DIV>
<DIV><FONT size=2 face=Arial></FONT> </DIV>
<DIV><FONT size=2 face=Arial>Joel Davidson</FONT></DIV>
<DIV> </DIV>
<DIV>----- Original Message ----- </DIV>
<BLOCKQUOTE
style="BORDER-LEFT: #000000 2px solid; PADDING-LEFT: 5px; PADDING-RIGHT: 0px; MARGIN-LEFT: 5px; MARGIN-RIGHT: 0px">
<DIV
style="FONT: 10pt arial; BACKGROUND: #e4e4e4; font-color: black"><B>From:</B>
<A title=dana@solarwork.com href="mailto:dana@solarwork.com">Dana</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 8:10
AM</DIV>
<DIV style="FONT: 10pt arial"><B>Subject:</B> [RE-wrenches] Battery based
hydrogen incidents</DIV>
<DIV><BR></DIV>
<DIV class=WordSection1>
<P class=MsoNormal><SPAN
style="FONT-FAMILY: 'Century Gothic','sans-serif'; COLOR: windowtext; FONT-SIZE: 14pt">Ken
<o:p></o:p></SPAN></P>
<P class=MsoNormal><SPAN
style="FONT-FAMILY: 'Century Gothic','sans-serif'; COLOR: windowtext; FONT-SIZE: 14pt"><o:p> </o:p></SPAN></P>
<P class=MsoNormal><SPAN
style="FONT-FAMILY: 'Century Gothic','sans-serif'; COLOR: windowtext; FONT-SIZE: 14pt">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-FAMILY: 'Century Gothic','sans-serif'; COLOR: windowtext; FONT-SIZE: 14pt"><o:p> </o:p></SPAN></P>
<P class=MsoNormal><SPAN
style="FONT-FAMILY: 'Century Gothic','sans-serif'; COLOR: windowtext; FONT-SIZE: 14pt"><o:p> </o:p></SPAN></P>
<P class=MsoNormal><SPAN
style="FONT-FAMILY: 'Century Gothic','sans-serif'; COLOR: windowtext; FONT-SIZE: 14pt">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-FAMILY: 'Century Gothic','sans-serif'; COLOR: windowtext; FONT-SIZE: 14pt"><o:p> </o:p></SPAN></P>
<P class=MsoNormal><SPAN
style="FONT-FAMILY: 'Century Gothic','sans-serif'; COLOR: windowtext; FONT-SIZE: 14pt">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-FAMILY: 'Century Gothic','sans-serif'; COLOR: windowtext; FONT-SIZE: 14pt"><o:p> </o:p></SPAN></P>
<P class=MsoNormal><SPAN
style="FONT-FAMILY: 'Century Gothic','sans-serif'; COLOR: windowtext; FONT-SIZE: 14pt"><o:p> </o:p></SPAN></P>
<P class=MsoNormal><SPAN
style="FONT-FAMILY: 'Century Gothic','sans-serif'; COLOR: windowtext; FONT-SIZE: 14pt"><o:p> </o:p></SPAN></P>
<DIV>
<P class=MsoNormal><SPAN
style="FONT-FAMILY: 'Century Gothic','sans-serif'; COLOR: windowtext">Dana
Orzel<o:p></o:p></SPAN></P>
<P class=MsoNormal><SPAN
style="FONT-FAMILY: 'Century Gothic','sans-serif'; COLOR: windowtext">Great
Solar Works, Inc<o:p></o:p></SPAN></P>
<P class=MsoNormal><SPAN
style="FONT-FAMILY: 'Century Gothic','sans-serif'; COLOR: windowtext">E -
dana@solarwork.com<o:p></o:p></SPAN></P>
<P class=MsoNormal><SPAN
style="FONT-FAMILY: 'Century Gothic','sans-serif'; COLOR: windowtext">V -
970.626.5253<o:p></o:p></SPAN></P>
<P class=MsoNormal><SPAN
style="FONT-FAMILY: 'Century Gothic','sans-serif'; COLOR: windowtext">F -
970.626.4140<o:p></o:p></SPAN></P>
<P class=MsoNormal><SPAN
style="FONT-FAMILY: 'Century Gothic','sans-serif'; COLOR: windowtext">C -
970.209.4076<o:p></o:p></SPAN></P>
<P class=MsoNormal><SPAN
style="FONT-FAMILY: 'Century Gothic','sans-serif'; COLOR: windowtext">web -
www.solarwork.com<o:p></o:p></SPAN></P>
<P class=MsoNormal><SPAN
style="FONT-FAMILY: 'Century Gothic','sans-serif'; COLOR: windowtext"><o:p> </o:p></SPAN></P>
<P class=MsoNormal><SPAN
style="FONT-FAMILY: 'Century Gothic','sans-serif'; COLOR: windowtext">"Responsible
Technologies for Responsible People since 1988"</SPAN><SPAN
style="FONT-FAMILY: 'Calibri','sans-serif'; COLOR: windowtext; FONT-SIZE: 11pt"><o:p></o:p></SPAN></P>
<P class=MsoNormal><SPAN
style="FONT-FAMILY: 'Century Gothic','sans-serif'; COLOR: windowtext">Do not
ever belive anything, but seriously trust through
action.<o:p></o:p></SPAN></P></DIV>
<P class=MsoNormal><SPAN
style="FONT-FAMILY: 'Century Gothic','sans-serif'; COLOR: windowtext; FONT-SIZE: 14pt"><o:p> </o:p></SPAN></P>
<DIV>
<DIV
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<P style="MARGIN-LEFT: 0.5in" class=MsoNormal><B><SPAN
style="FONT-FAMILY: 'Tahoma','sans-serif'; COLOR: windowtext; FONT-SIZE: 10pt">From:</SPAN></B><SPAN
style="FONT-FAMILY: 'Tahoma','sans-serif'; COLOR: windowtext; FONT-SIZE: 10pt">
re-wrenches-bounces@lists.re-wrenches.org
[mailto:re-wrenches-bounces@lists.re-wrenches.org] <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 style="MARGIN-LEFT: 0.5in" class=MsoNormal><o:p> </o:p></P>
<P style="MARGIN-LEFT: 0.5in" class=MsoNormal>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">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>
<P>
<HR>
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