Wrenches, Good points. To recap: Max recommended strings in parallel on cyclic applications is 1 to 3. More than 3 strings in parallel will over time promote unbalanced charge of the strings. Unbalanced charge will promote sulfatation (lead sulfate crystals hardening) of the plates on the units not getting enough charge, and, promote corrosion (due to loosing water) & possibly thermal challenges on the “boiling” overcharged units, while accelerating batteries ageing on all.
In addition to the issue of the max number of strings in parallel, batteries need to see full charge (system design) to stay in good health. FLA batteries need to see equalization when the S.G delta between cells are reaching 30 points difference. Equalization on FLA batteries addresses S.G. unbalance and acid stratification, both of which are challenging the battery health. John Trojan Battery Company From: re-wrenches-boun...@lists.re-wrenches.org [mailto:re-wrenches-boun...@lists.re-wrenches.org] On Behalf Of Drake Sent: Friday, April 13, 2012 9:41 AM To: Darryl Thayer; RE-wrenches Subject: Re: [RE-wrenches] Hot Trojan Batteries 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 <ja...@fafcosolar.com<mailto:ja...@fafcosolar.com>> To: RE-wrenches <re-wrenches@lists.re-wrenches.org<mailto:re-wrenches@lists.re-wrenches.org>> 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) 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. Jason Szumlanski Fafco Solar From: re-wrenches-boun...@lists.re-wrenches.org<mailto:re-wrenches-boun...@lists.re-wrenches.org> [ mailto:re-wrenches-boun...@lists.re-wrenches.org] On Behalf Of John DeBoever Sent: Monday, April 02, 2012 12:14 PM To: allso...@scswifi.net<mailto:allso...@scswifi.net>; 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<http://www.trojanbatteryre.com/Tech_Support/Tech_Support.html?tab=0#TabbedPanels1top> 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 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 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 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 jdeboe...@trojanbattery.com<mailto:jdeboe...@trojanbattery.com> www.trojanbattery.com<http://www.trojanbattery.com/> -----Original Message----- From: re-wrenches-boun...@lists.re-wrenches.org<mailto:re-wrenches-boun...@lists.re-wrenches.org> [ mailto:re-wrenches-boun...@lists.re-wrenches.org] On Behalf Of allso...@scswifi.net<mailto:allso...@scswifi.net> Sent: Sunday, April 01, 2012 7:20 PM To: re-wrenches@lists.re-wrenches.org<mailto:re-wrenches@lists.re-wrenches.org> 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! _______________________________________________ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org<mailto:RE-wrenches@lists.re-wrenches.org> Options & settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules & etiquette: www.re-wrenches.org/etiquette.htm<http://www.re-wrenches.org/etiquette.htm> Check out participant bios: www.members.re-wrenches.org<http://www.members.re-wrenches.org> This e-mail message and any attachments that accompany it may contain information that is confidential, privileged, or protected from disclosure. It is intended solely for the use of the individual(s) to whom it was intended to be addressed. If you have received this e-mail by mistake, or you are not the intended recipient, any reading, disclosure, copying or other use of this communication is strictly prohibited. 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Thank you. _______________________________________________ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org<mailto:RE-wrenches@lists.re-wrenches.org> Options & settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules & etiquette: www.re-wrenches.org/etiquette.htm<http://www.re-wrenches.org/etiquette.htm> Check out participant bios: www.members.re-wrenches.org<http://www.members.re-wrenches.org/> _______________________________________________ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org<mailto:RE-wrenches@lists.re-wrenches.org> Options & settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules & etiquette: www.re-wrenches.org/etiquette.htm<http://www.re-wrenches.org/etiquette.htm> Check out participant bios: www.members.re-wrenches.org<http://www.members.re-wrenches.org/> Drake Chamberlin ATHENS ELECTRIC LLC OH License 44810 CO license 3773 NABCEP Certified PV This e-mail message and any attachments that accompany it may contain information that is confidential, privileged, or protected from disclosure. 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