I've seen batteries get very hot from deficit
charging, where batteries are cycled rapidly and never fully charged.
At 10:15 PM 4/12/2012, you wrote:
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.
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.
From: Jason Szumlanski <[email protected]>
To: RE-wrenches <[email protected]>
Sent: Monday, April 2, 2012 11:53 AM
Subject: Re: [RE-wrenches] Hot Trojan Batteries
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) weâre
talking about charging at a 16.25 amp rate.
Iâm sure John is not referring to a maximum
rate of 10-15% of 16.25 amps, but 10-15% of the 325aH capacity.
Jason Szumlanski
Fafco Solar
From:
<mailto:[email protected]>[email protected]
[mailto:[email protected]] On Behalf Of John DeBoever
Sent: Monday, April 02, 2012 12:14 PM
To: <mailto:[email protected]>[email protected]; RE-wrenches
Subject: Re: [RE-wrenches] Hot Trojan Batteries
Jeremy, Wrenches,
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
http://www.trojanbatteryre.com/Tech_Support/Tech_Support.html?tab=0#TabbedPanels1#top
Below are few perspectives to help the diagnostic:
o System issues:
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.
ü Check Voltage settings: these are provided
on Trojan datasheets, see here:
http://www.trojanbatteryre.com/Tech_Support/literature.html
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
ü Check Voltage sensor status and connection.
Dedicated wiring is recommended
ü Check temperature sensor. It shall be well
positioned, typically in the middle of the battery bank at the warmest point.
ü Check if air circulation between the battery units.
ü Check if adequate air ventilation of the battery room.
o Battery issues:
ü C/20 charging rate is too high (see above)
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
20oF above ambient temperature, and typical min
and max limit are -4°F to 113°F.
See here:
<http://www.trojanbatteryre.com/PDF/Signature_Trojan_ProductLineSheet.pdf>http://www.trojanbatteryre.com/PDF/Signature_Trojan_ProductLineSheet.pdf
165°F is way too high and will damage the units
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.
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:
<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
ü Please deal directly off-Wrenches list, with
Trojan Tech Support for better fine tune
resolution:
<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
I hope this help,
John
John F. DeBoever
Global Technical Director Renewable Energy
Trojan Battery Company
12380 Clark Street
Santa Fe Springs, CA 90670
Tel: +1-562-236-3000 Ext. 3139
Cell: +1-845-514-7600 NY office time zone: USA EST (GMT-5)<
Skype: john.f.deboever
Fax: +1-562-236-3239
<mailto:[email protected]>[email protected]
www.trojanbattery.com
-----Original Message-----
From:
<mailto:[email protected]>[email protected]
[mailto:[email protected]]
On Behalf Of <mailto:[email protected]>[email protected]
Sent: Sunday, April 01, 2012 7:20 PM
To:
<mailto:[email protected]>[email protected]
Subject: [RE-wrenches] Hot Trojan Batteries
Wrenches,
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
Jeremy
All Solar
Sent via BlackBerry. Sorry for typos and shorthand!
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