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." <[email protected]> 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 <[email protected]> > *To:* RE-wrenches <[email protected]> > *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:* [email protected] [mailto: > [email protected]] *On Behalf Of *Allan Sindelar > *Sent:* Monday, April 02, 2012 1:46 PM > *To:* [email protected] > *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* > [email protected] > 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:* [email protected] [ > mailto:[email protected]<[email protected]>] > *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:* [email protected] [mailto: > [email protected]] *On Behalf Of *John DeBoever > *Sent:* Monday, April 02, 2012 12:14 PM > *To:* [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 > > 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 > > [email protected] > > www.trojanbattery.com > > > > -----Original Message----- > From: [email protected] [ > mailto:[email protected]<[email protected]>] > On Behalf Of [email protected] > Sent: Sunday, April 01, 2012 7:20 PM > To: [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! > > _______________________________________________ > > List sponsored by Home Power magazine > > > > List Address: [email protected] > > > > 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 > > > > Check out participant bios: > > 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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