One of the biggest issues I find w/ battery installations is instead of using larger capacity 2 volt cell batteries, there are “installers” that install string after string of 6VDC batteries and wire them without buss bars, so the last string contributes very little during discharge & gets very little charging. Who really wants to take service 144 battery filler wells? (2100 Ahr when using L16s@ 350Ahr for 48 vdc.) Its no wonder why battery banks suffer from neglect. According to Surrette's battery installation and warrantee guide for # of maximum strings per battery bank; Preferably 2 no more then 3 strings. ( Steve please correct me here). Buss bars are cheap, when amortized over the life cycle of an installation and are easily configured W/ shunts if one choses to install multiple strings. Buss bars also improve battery performance both during discharging & charging, & they also facility the installation of an inline class “T” fuse > On Jul 18, 2018, at 9:33 PM, William Miller <[email protected]> wrote: > > Colleagues: > > I believe that circulating currents in multi-string battery installations are > a major cause of premature failure of such a system. I think it is important > to monitor these currents. Most telling would be checking these currents in > an at-rest scenario. It would be helpful to have a baseline at install and > then check periodically. > > Measuring these currents with any type of DC clamp-on meter can be inaccurate > at best. In a conversation with Steve Higgins at a recent trade show I came > up with this idea that may have some merit: If an install has more than one > string of batteries, install an appropriately sized shunt in the negative > lead of each string. At any later date you can apply any decent voltmeter > with a millivolt scale and check for battery string imbalance with some > degree of accuracy. Shunts are cheap and readily available and if you avoid > the brand that Outback uses in the Radian GSLC cabinets, they are relatively > rugged. > > We will be trying this in any future install with multiple strings, although > we avoid this if at all possible. > > William Miller > > <image002.jpg> > Lic 773985 > millersolar.com <http://www.millersolar.com/> > 805-438-5600 > > From: RE-wrenches [mailto:[email protected] > <mailto:[email protected]>] On Behalf Of John > Blittersdorf > Sent: Wednesday, July 18, 2018 6:24 PM > To: RE-wrenches > Subject: Re: [RE-wrenches] Electrolyte Dilution vs Voltage > > Mac, > I was about to ditto Ray with his more common than I would like scenario of > battery death when I saw your mention of the 2nd string not connected. It is > always nice to see > a solution that is simple and should have been considered, but wasn't. The > assumption with battery issues usually is that they are actually hooked up! > I often thought that it would be worth the money to supply a cheap AC/DC > clamp meter with every installation so that a phone consultation could > quickly determine if the strings were unbalanced and what might be the > reason. Bad cells and bad connection will usually show up in a current > check and then a quick voltage check of each battery with a load on the > system will show the culprit if a bad cell and corrosion present might find > the bad connection. I use Interstate L16's most of the time and find that > the life is typically 6 years. I used to call them a 7 to 10 year battery > but kept racheting back the claim until I now call them a 5 to 7 year battery > with more if properly maintained. I have seen 10 years but it is rare. > > John Blittersdorf > _______________________________________________ > List sponsored by Redwood Alliance > > List Address: [email protected] > <mailto:[email protected]> > > Change listserver email address & settings: > http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org > <http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org> > > List-Archive: > http://www.mail-archive.com/[email protected]/maillist.html > <http://www.mail-archive.com/[email protected]/maillist.html> > > List rules & etiquette: > www.re-wrenches.org/etiquette.htm <http://www.re-wrenches.org/etiquette.htm> > > Check out or update participant bios: > www.members.re-wrenches.org <http://www.members.re-wrenches.org/> > [email protected] > <blocked::mailto:[email protected]%22%20%5Co%20%22blocked::mailto:[email protected]> > www.SWNL.net > <blocked::http://www.swnl.net/%22%20%5Co%20%22blocked::http://www.swnl.net/> > Solarwinds Northernlights > Serving Mid Coast Maine & Northern California > 207-832-7574 Cl. 610-517-8401 > > Blair "TUMP" May > ******** MAINE'S CHARTER ******** > NABCEP "Certified PV Installer" > > ******** MAINE'S CHARTER ******** > Trace Xantrex "Certified" Dealer / Installer" >
_______________________________________________ List sponsored by Redwood Alliance List Address: [email protected] Change listserver email address & settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://www.mail-archive.com/[email protected]/maillist.html List rules & etiquette: www.re-wrenches.org/etiquette.htm Check out or update participant bios: www.members.re-wrenches.org
