<table cellspacing="0" cellpadding="0" border="0" ><tr><td valign="top" style="font: inherit;"><DIV>Some really good lessons here, thanks Larry </DIV>
<DIV> </DIV>
<DIV>I forgot to mention one of my explosions, I was checking connections and found one loose but I had turned off the battery bank. but there were four parallel strings connected I believe the string I was working on had a small current flowing or some thing because moving the cable to test connection caused expolision. <BR></DIV>
<DIV>Inside the battery is hydrogne and oxygen in the perfect ratio, it detonates, with almost any spark, I am sure the flame kernel is much smaller than gasoline in air for example. </DIV>
<DIV>Darryl<BR>--- On <B>Wed, 12/15/10, Starlight Solar, Larry Crutcher <I><larry@starlightsolar.com></I></B> wrote:<BR></DIV>
<BLOCKQUOTE style="BORDER-LEFT: rgb(16,16,255) 2px solid; PADDING-LEFT: 5px; MARGIN-LEFT: 5px"><BR>From: Starlight Solar, Larry Crutcher <larry@starlightsolar.com><BR>Subject: Re: [RE-wrenches] Battery based hydrogen incidents<BR>To: "RE-wrenches" <re-wrenches@lists.re-wrenches.org><BR>Date: Wednesday, December 15, 2010, 1:35 PM<BR><BR>
<DIV id=yiv774257597>
<DIV><FONT size=2 face=Arial>I was hesitant to reply because I surely will look foolish, but perhaps it may help someone in the future. </FONT><FONT size=2 face=Arial>I did something very stupid back in 2001 that caused an explosion. </FONT></DIV>
<DIV><FONT size=2 face=Arial></FONT> </DIV>
<DIV><FONT size=2 face=Arial>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 size=2 face=Arial>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 size=2 face=Arial></FONT> </DIV>
<DIV><FONT size=2 face=Arial>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 size=2 face=Arial>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 size=2 face=Arial></FONT> </DIV>
<DIV><FONT size=2 face=Arial>Larry Crutcher</FONT></DIV>
<DIV><FONT size=2 face=Arial>Starlight Solar Power Systems</FONT></DIV>
<DIV><FONT size=2 face=Arial>928-342-9103</FONT></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">----- Original Message ----- </DIV>
<DIV style="FONT: 10pt arial; BACKGROUND: #e4e4e4"><B>From:</B> <A title=kent@coveoregon.com href="http://us.mc393.mail.yahoo.com/mc/compose?to=kent@coveoregon.com" rel=nofollow target=_blank ymailto="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="http://us.mc393.mail.yahoo.com/mc/compose?to=re-wrenches@lists.re-wrenches.org" rel=nofollow target=_blank ymailto="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 type="cite">
<STYLE> _filtered #yiv774257597 {
font-family:Calibri;}
_filtered #yiv774257597 {
font-family:Tahoma;}
_filtered #yiv774257597 {
font-family:Century Gothic;}
_filtered #yiv774257597 {margin:1.0in 1.0in 1.0in 1.0in;}
#yiv774257597 P.yiv774257597MsoNormal {
FONT-SIZE:12pt;MARGIN:0in 0in 0pt;COLOR:black;FONT-FAMILY:"serif";}
#yiv774257597 LI.yiv774257597MsoNormal {
FONT-SIZE:12pt;MARGIN:0in 0in 0pt;COLOR:black;FONT-FAMILY:"serif";}
#yiv774257597 DIV.yiv774257597MsoNormal {
FONT-SIZE:12pt;MARGIN:0in 0in 0pt;COLOR:black;FONT-FAMILY:"serif";}
#yiv774257597 A:link {
COLOR:blue;TEXT-DECORATION:underline;}
#yiv774257597 SPAN.yiv774257597MsoHyperlink {
COLOR:blue;TEXT-DECORATION:underline;}
#yiv774257597 A:visited {
COLOR:purple;TEXT-DECORATION:underline;}
#yiv774257597 SPAN.yiv774257597MsoHyperlinkFollowed {
COLOR:purple;TEXT-DECORATION:underline;}
#yiv774257597 SPAN.yiv774257597EmailStyle17 {
FONT-WEIGHT:normal;COLOR:windowtext;FONT-STYLE:normal;FONT-FAMILY:"sans-serif";TEXT-DECORATION:none;}
#yiv774257597 .yiv774257597MsoChpDefault {
FONT-SIZE:10pt;}
#yiv774257597 DIV.yiv774257597WordSection1 {
}
</STYLE>
<DIV class=yiv774257597WordSection1>
<P class=yiv774257597MsoNormal><SPAN style="FONT-FAMILY: 'sans-serif'; COLOR: windowtext; FONT-SIZE: 14pt">Ken – </SPAN></DIV>
<P class=yiv774257597MsoNormal><SPAN style="FONT-FAMILY: 'sans-serif'; COLOR: windowtext; FONT-SIZE: 14pt"></SPAN></DIV>
<P class=yiv774257597MsoNormal><SPAN style="FONT-FAMILY: '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.</SPAN></DIV>
<P class=yiv774257597MsoNormal><SPAN style="FONT-FAMILY: 'sans-serif'; COLOR: windowtext; FONT-SIZE: 14pt"></SPAN></DIV>
<P class=yiv774257597MsoNormal><SPAN style="FONT-FAMILY: 'sans-serif'; COLOR: windowtext; FONT-SIZE: 14pt"></SPAN></DIV>
<P class=yiv774257597MsoNormal><SPAN style="FONT-FAMILY: '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.</SPAN></DIV>
<P class=yiv774257597MsoNormal><SPAN style="FONT-FAMILY: 'sans-serif'; COLOR: windowtext; FONT-SIZE: 14pt"></SPAN></DIV>
<P class=yiv774257597MsoNormal><SPAN style="FONT-FAMILY: 'sans-serif'; COLOR: windowtext; FONT-SIZE: 14pt">Q - How many battery based hydrogen incidents have happened in our collective experience?</SPAN></DIV>
<P class=yiv774257597MsoNormal><SPAN style="FONT-FAMILY: 'sans-serif'; COLOR: windowtext; FONT-SIZE: 14pt"></SPAN></DIV>
<P class=yiv774257597MsoNormal><SPAN style="FONT-FAMILY: 'sans-serif'; COLOR: windowtext; FONT-SIZE: 14pt"></SPAN></DIV>
<P class=yiv774257597MsoNormal><SPAN style="FONT-FAMILY: 'sans-serif'; COLOR: windowtext; FONT-SIZE: 14pt"></SPAN></DIV>
<DIV>
<P class=yiv774257597MsoNormal><SPAN style="FONT-FAMILY: 'sans-serif'; COLOR: windowtext">Dana Orzel</SPAN></DIV>
<P class=yiv774257597MsoNormal><SPAN style="FONT-FAMILY: 'sans-serif'; COLOR: windowtext">Great Solar Works, Inc</SPAN></DIV>
<P class=yiv774257597MsoNormal><SPAN style="FONT-FAMILY: 'sans-serif'; COLOR: windowtext">E - <A class=yiv774257597moz-txt-link-abbreviated href="http://us.mc393.mail.yahoo.com/mc/compose?to=dana@solarwork.com" rel=nofollow target=_blank ymailto="mailto:dana@solarwork.com">dana@solarwork.com</A></SPAN></DIV>
<P class=yiv774257597MsoNormal><SPAN style="FONT-FAMILY: 'sans-serif'; COLOR: windowtext">V - 970.626.5253</SPAN></DIV>
<P class=yiv774257597MsoNormal><SPAN style="FONT-FAMILY: 'sans-serif'; COLOR: windowtext">F - 970.626.4140</SPAN></DIV>
<P class=yiv774257597MsoNormal><SPAN style="FONT-FAMILY: 'sans-serif'; COLOR: windowtext">C - 970.209.4076</SPAN></DIV>
<P class=yiv774257597MsoNormal><SPAN style="FONT-FAMILY: 'sans-serif'; COLOR: windowtext">web - <A class=yiv774257597moz-txt-link-abbreviated href="http://www.solarwork.com/" rel=nofollow target=_blank>www.solarwork.com</A></SPAN></DIV>
<P class=yiv774257597MsoNormal><SPAN style="FONT-FAMILY: 'sans-serif'; COLOR: windowtext"></SPAN></DIV>
<P class=yiv774257597MsoNormal><SPAN style="FONT-FAMILY: 'sans-serif'; COLOR: windowtext">"Responsible Technologies for Responsible People since 1988"</SPAN><SPAN style="FONT-FAMILY: 'sans-serif'; COLOR: windowtext; FONT-SIZE: 11pt"></SPAN></DIV>
<P class=yiv774257597MsoNormal><SPAN style="FONT-FAMILY: 'sans-serif'; COLOR: windowtext">Do not ever belive anything, but seriously trust through action.</SPAN></DIV></DIV>
<P class=yiv774257597MsoNormal><SPAN style="FONT-FAMILY: 'sans-serif'; COLOR: windowtext; FONT-SIZE: 14pt"></SPAN></DIV>
<DIV>
<DIV style="BORDER-BOTTOM: medium none; BORDER-LEFT: medium none; PADDING-BOTTOM: 0in; PADDING-LEFT: 0in; PADDING-RIGHT: 0in; BORDER-TOP: rgb(181,196,223) 1pt solid; BORDER-RIGHT: medium none; PADDING-TOP: 3pt">
<P style="MARGIN-LEFT: 0.5in" class=yiv774257597MsoNormal><B><SPAN style="FONT-FAMILY: 'sans-serif'; COLOR: windowtext; FONT-SIZE: 10pt">From:</SPAN></B><SPAN style="FONT-FAMILY: 'sans-serif'; COLOR: windowtext; FONT-SIZE: 10pt"> <A class=yiv774257597moz-txt-link-abbreviated href="http://us.mc393.mail.yahoo.com/mc/compose?to=re-wrenches-bounces@lists.re-wrenches.org" rel=nofollow target=_blank ymailto="mailto:re-wrenches-bounces@lists.re-wrenches.org">re-wrenches-bounces@lists.re-wrenches.org</A> [<A class=yiv774257597moz-txt-link-freetext href="http://us.mc393.mail.yahoo.com/mc/compose?to=re-wrenches-bounces@lists.re-wrenches.org" rel=nofollow target=_blank ymailto="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</SPAN></DIV></DIV></DIV>
<P style="MARGIN-LEFT: 0.5in" class=yiv774257597MsoNormal></DIV>
<P style="MARGIN-LEFT: 0.5in" class=yiv774257597MsoNormal>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" rel=nofollow target=_blank>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</DIV></DIV><PRE><HR SIZE=4 width="90%">
_______________________________________________
List sponsored by Home Power magazine
List Address: <A class=yiv774257597moz-txt-link-abbreviated href="http://us.mc393.mail.yahoo.com/mc/compose?to=RE-wrenches@lists.re-wrenches.org" rel=nofollow target=_blank ymailto="mailto:RE-wrenches@lists.re-wrenches.org">RE-wrenches@lists.re-wrenches.org</A>
Options & settings:
<A class=yiv774257597moz-txt-link-freetext href="http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org" rel=nofollow target=_blank>http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org</A>
List-Archive: <A class=yiv774257597moz-txt-link-freetext href="http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org" rel=nofollow target=_blank>http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org</A>
List rules & etiquette:
<A class=yiv774257597moz-txt-link-abbreviated href="http://www.re-wrenches.org/etiquette.htm" rel=nofollow target=_blank>www.re-wrenches.org/etiquette.htm</A>
Check out participant bios:
<A class=yiv774257597moz-txt-link-abbreviated href="http://www.members.re-wrenches.org/" rel=nofollow target=_blank>www.members.re-wrenches.org</A>
</PRE></BLOCKQUOTE>
<DIV>
<HR>
<DIV></DIV>_______________________________________________<BR>List sponsored by Home Power magazine<BR><BR>List Address: RE-wrenches@lists.re-wrenches.org<BR><BR>Options & settings:<BR>http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org<BR><BR>List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org<BR><BR>List rules & etiquette:<BR>www.re-wrenches.org/etiquette.htm<BR><BR>Check out participant bios:<BR>www.members.re-wrenches.org<BR><BR></BLOCKQUOTE></DIV><BR>-----Inline Attachment Follows-----<BR><BR>
<DIV class=plainMail>_______________________________________________<BR>List sponsored by Home Power magazine<BR><BR>List Address: <A href="http://us.mc393.mail.yahoo.com/mc/compose?to=RE-wrenches@lists.re-wrenches.org" ymailto="mailto:RE-wrenches@lists.re-wrenches.org">RE-wrenches@lists.re-wrenches.org</A><BR><BR>Options & settings:<BR><A href="http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org" target=_blank>http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org</A><BR><BR>List-Archive: <A href="http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org" target=_blank>http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org</A><BR><BR>List rules & etiquette:<BR>www.re-wrenches.org/etiquette.htm<BR><BR>Check out participant bios:<BR>www.members.re-wrenches.org<BR><BR></DIV></BLOCKQUOTE></td></tr></table><br>