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I've seen batteries get very hot from deficit charging, where batteries
are cycled rapidly and never fully charged. <br><br>
<br>
At 10:15 PM 4/12/2012, you wrote:<br>
<blockquote type=cite class=cite cite="">I have seen very hot batteries
infact batteries that melted. and caught fire. the problem
was that the string was several strings in parallel, and one of the
strings had thermal runaway. during charge one battery got hot, and
it has lower voltage and gets more current. then it get hotter because of
the more curent. soon it is so hot the other batteries start to discharge
through the hot battery. <br>
<br>
A similar event will occur when one battery in a string of batteries
develops a bad cell, and the othe batteries in parallel strings will
force current backwards through the cell. and thermal runaway
occcurs in the hot battery. <br><br>
<font size=2><b>From:</b> Jason Szumlanski
<jason@fafcosolar.com><br>
<b>To:</b> RE-wrenches <re-wrenches@lists.re-wrenches.org> <br>
<b>Sent:</b> Monday, April 2, 2012 11:53 AM<br>
<b>Subject:</b> Re: [RE-wrenches] Hot Trojan Batteries<br>
</font><br>
There must be some confusion here about the charging rate. C/20 refers to
capacity divided by 20, so in the case of a 325aH battery (capacity @ the
20 hour discharge rate) we’re talking about charging at a 16.25 amp
rate. I’m sure John is not referring to a maximum rate of 10-15% of
16.25 amps, but 10-15% of the 325aH capacity.<br>
<br>
Jason Szumlanski<br>
Fafco Solar<br>
<br>
<br>
<b>From:</b>
<a href="mailto:re-wrenches-bounces@lists.re-wrenches.org">
re-wrenches-bounces@lists.re-wrenches.org</a>
[<a href="mailto:re-wrenches-bounces@lists.re-wrenches.org" eudora="autourl">
mailto:re-wrenches-bounces@lists.re-wrenches.org</a>] <b>On Behalf Of
</b>John DeBoever<br>
<b>Sent:</b> Monday, April 02, 2012 12:14 PM<br>
<b>To:</b>
<a href="mailto:allsolar@scswifi.net">allsolar@scswifi.net</a>;
RE-wrenches<br>
<b>Subject:</b> Re: [RE-wrenches] Hot Trojan Batteries<br>
<br>
Jeremy, Wrenches,<br>
<br>
165°F is definitely too high and you should stop immediately any charge
to avoid further major problems. I recommend you contact our Trojan Tech
Support for help at
<a href="http://www.trojanbatteryre.com/Tech_Support/Tech_Support.html?tab=0#TabbedPanels1top" eudora="autourl">
http://www.trojanbatteryre.com/Tech_Support/Tech_Support.html?tab=0#TabbedPanels1#top</a>
<br>
<br>
Below are few perspectives to help the diagnostic:<br>
<br>
o System issues: <br>
ü Check Charger setting: the C/20 rate mentioned is definitely too
high and will damage the battery. The maximum recommended current rate is
10-15% of C/20 for a deep-cycle flooded lead acid battery. Other C/rates
are possible but are application specific and not typical.<br>
ü Check Voltage settings: these are provided on Trojan datasheets,
see here:
<a href="http://www.trojanbatteryre.com/Tech_Support/literature.html" eudora="autourl">
http://www.trojanbatteryre.com/Tech_Support/literature.html</a> <br>
ü Check Temperature compensation: -0.028VPC for every 10°F above
77°F (add 0.028 VPC for every 10°F below 77°F or subtract 0.020VPC for
every 10°F above 77°F. See here:
http://www.trojanbatteryre.com/PDF/Signature_Trojan_ProductLineSheet.pdf
<br>
ü Check Voltage sensor status and connection. Dedicated wiring is
recommended<br>
ü Check temperature sensor. It shall be well positioned, typically
in the middle of the battery bank at the warmest point.<br>
ü Check if air circulation between the battery units. <br>
ü Check if adequate air ventilation of the battery room.<br>
<br>
o Battery issues:<br>
ü C/20 charging rate is too high (see above)<br>
ü How old are the batteries? Ageing batteries will face
micro-shorts that will decrease the battery turnaround efficiency over
time that translates in higher temperature generation. Typically the
battery temperature range is about 20<sup>o</sup>F above ambient
temperature, and typical min and max limit are -4°F to 113°F. <br>
See here:
<a href="http://www.trojanbatteryre.com/PDF/Signature_Trojan_ProductLineSheet.pdf">
http://www.trojanbatteryre.com/PDF/Signature_Trojan_ProductLineSheet.pdf</a>
<br>
165°F is way too high and will damage the units<br>
ü Maybe you are facing one or more shorted units: check the
voltage and it will quickly indicate if a unit is shorted. Shorted
units will generate heat and will jeopardize the charging of other units.
Remove shorted units and consult tech support your charger supplier if
possible to reconfigure of your battery bank with fewer units, configured
at a lower battery bank voltage, using same voltage settings recommended
by Trojan Battery Company. Typically 1 to 3 units less would be
acceptable, depending the charger manufacturer settings.<br>
ü Maybe you are facing sulfated batteries, resulting from low
charging, thus resulting in lower overall turnaround efficiency. This
will heat some healthier units of the battery bank, accelerating
corrosion damages. The max temperature acceptable being 113°F, please
consult Trojan Tech Support:
<a href="http://www.trojanbatteryre.com/Tech_Support/Tech_Support.html?tab=0#TabbedPanels1#top">
http://www.trojanbatteryre.com/Tech_Support/Tech_Support.html?tab=0#TabbedPanels1#top</a>
<br>
ü Please deal directly off-Wrenches list, with Trojan Tech Support
for better fine tune resolution:
<a href="http://www.trojanbatteryre.com/Tech_Support/Tech_Support.html?tab=0#TabbedPanels1#top">
http://www.trojanbatteryre.com/Tech_Support/Tech_Support.html?tab=0#TabbedPanels1#top</a>
<br>
<br>
I hope this help,<br>
<br>
John<br>
John F. DeBoever<br>
Global Technical Director – Renewable Energy<br>
<b>Trojan Battery Company<br>
</b> <br>
12380 Clark Street <br>
Santa Fe Springs, CA 90670<br>
Tel: +1-562-236-3000 Ext. 3139<br>
<b>Cell: +1-845-514-7600 – NY office time zone: USA EST
(GMT-5)</b><<br>
Skype: john.f.deboever<br>
Fax: +1-562-236-3239<br>
<a href="mailto:jdeboever@trojanbattery.com">
jdeboever@trojanbattery.com</a><br>
<a href="http://www.trojanbattery.com/" eudora="autourl">
www.trojanbattery.com</a><br>
<br>
-----Original Message-----<br>
From:
<a href="mailto:re-wrenches-bounces@lists.re-wrenches.org">
re-wrenches-bounces@lists.re-wrenches.org</a>
[<a href="mailto:re-wrenches-bounces@lists.re-wrenches.org" eudora="autourl">
mailto:re-wrenches-bounces@lists.re-wrenches.org</a>] On Behalf Of
<a href="mailto:allsolar@scswifi.net">allsolar@scswifi.net</a><br>
Sent: Sunday, April 01, 2012 7:20 PM<br>
To:
<a href="mailto:re-wrenches@lists.re-wrenches.org">
re-wrenches@lists.re-wrenches.org</a><br>
Subject: [RE-wrenches] Hot Trojan Batteries<br>
<br>
Wrenches,<br>
Can anyone explain why an L16 bank would be at 165F at rest. Over a
C20 charge rate, but I have a feeling there might be an internal short
<br>
<br>
Jeremy<br>
All Solar<br>
Sent via BlackBerry. Sorry for typos and shorthand!<br>
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