[RE-wrenches] Charge Rate (Hot Trojan Batteries)

Tue Apr 3 07:31:27 PDT 2012

5 strings says it all!  now would be a good opportunity to replace with
higher capacity cells and fewer strings for long lasting
performance......Kirpal
On Apr 3, 2012 7:21 AM, "All Solar, Inc." <allsolar at scswifi.net> wrote:

> **
> With 5 strings installed, I figured the charge rate to be about 3.3% (of
> C20 rate) for 5 years or so. Actually since it was installed in 2002, and
> now on its second set of batteries.
> We added some PV and an MX60 a year ago, and now this.  I think he
> had heavily sulfated batteries which eventually led to shorted cells. ?
> Jeremy
>
> ----- Original Message -----
> *From:* Jason Szumlanski <jason at fafcosolar.com>
> *To:* RE-wrenches <re-wrenches at lists.re-wrenches.org>
> *Sent:* Monday, April 02, 2012 1:43 PM
> *Subject:* Re: [RE-wrenches] Hot Trojan Batteries
>
>  There are a lot of forums and circles where C/20 refers to the capacity
> divided by 20, or 5% of the battery capacity. This may be the more informal
> interpretation of the term, but you will find many examples where people
> consider C/20 to be 5% of the capacity (wrong or right). For example, look
> at the most frequently accessed deep cycle charging FAQ on the Internet:
> http://www.windsun.com/Batteries/Battery_FAQ.htm
>
>
>
> To be clear perhaps we should just use plain English and say “the
> recommended charging rate is 10-15% of the capacity of the battery at the
> 20 hour discharge rate.”
>
>
>
> Jason Szumlanski
>
> Fafco Solar
>
>
>
>
>
> *From:* re-wrenches-bounces at lists.re-wrenches.org [mailto:
> re-wrenches-bounces at lists.re-wrenches.org] *On Behalf Of *Allan Sindelar
> *Sent:* Monday, April 02, 2012 1:46 PM
> *To:* re-wrenches at lists.re-wrenches.org
> *Subject:* Re: [RE-wrenches] Hot Trojan Batteries
>
>
>
> Wrenches,
> I attended John DeBoever's Friday afternoon presentation on battery
> technology and care at the NABCEP Continuing Education conference this past
> weekend. It quickly became clear to me that John seriously knows his
> batteries, at all levels: chemistry, physics, RE use and care, etc. It was
> an advanced-level presentation, and I learned a lot.
>
> The first thing John told us was that English is not his native language;
> he's a Belgian raised in South Africa (and more that I didn't catch). He
> was bursting with knowledge and good information, but occasionally we in
> his class would back him up to better explain a point.
>
> In short, I think he will be a real asset to the Wrenches list as a
> manufacturer's representative. And occasionally there will be something
> confusing, such as what just happened here. I too wondered about C20 versus
> C/20. I appreciate that he quickly cleared up the confusion, and look
> forward to learning quite a bit from his posts about battery issues.
> Allan
>
> *Allan Sindelar*
> Allan at positiveenergysolar.com
> NABCEP Certified Photovoltaic Installer
> NABCEP Certified Technical Sales Professional
> New Mexico EE98J Journeyman Electrician
> *Positive Energy, Inc.*
> 3201 Calle Marie
> Santa Fe, New Mexico 87507
> *505 424-1112*
> www.positiveenergysolar.com
>
>
>
>
>
>
> On 4/2/2012 11:00 AM, John DeBoever wrote:
>
> Jason, Wrenches,
>
>
>
> C/20 means C over 20 hours discharge rate = capacity @ the 20 hours
> discharge rate. C/20 often is mentioned as C20, so the confusion here.
>
> Max recommended is 10& to 15% of C20 of the battery bank.
>
>
>
> John
>
> Trojan Battery Company
>
>
>
> *From:* re-wrenches-bounces at lists.re-wrenches.org [
> mailto:re-wrenches-bounces at lists.re-wrenches.org<re-wrenches-bounces at lists.re-wrenches.org>]
> *On Behalf Of *Jason Szumlanski
> *Sent:* Monday, April 02, 2012 12:53 PM
> *To:* RE-wrenches
> *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-bounces at lists.re-wrenches.org [mailto:
> re-wrenches-bounces at lists.re-wrenches.org] *On Behalf Of *John DeBoever
> *Sent:* Monday, April 02, 2012 12:14 PM
> *To:* allsolar at 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
>
>
>
> 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
>
> jdeboever at trojanbattery.com
>
> www.trojanbattery.com
>
>
>
> -----Original Message-----
> From: re-wrenches-bounces at lists.re-wrenches.org [
> mailto:re-wrenches-bounces at lists.re-wrenches.org<re-wrenches-bounces at lists.re-wrenches.org>]
> On Behalf Of allsolar at scswifi.net
> Sent: Sunday, April 01, 2012 7:20 PM
> To: re-wrenches at 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!
>
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