Let me chime in here, Any battery will be runined if it is left discharged. If it is deeply discharged it will destroy faster. I do not think an AGM battery is the same as a cycling battery. I have always had better luck with a flooded battery for cycling. With a Flooded it can be tested with a hydrometer, you can equlize, you can over charge and just lose water. No battery can take undercharging or low state of charge. The AGM battery is excellent for backup power to a grid tied system. Where it cycles only a few times in its life, the rest of the time it is held just above resting voltage. The charge rate such that the internal recombination can keep up with the current. I have found that AGM keep there charge with very low self discharge, people have reported life expectancys of over 5 years under these conditions. However you never know the remaining capacity unless you do a discharge cycle.
For flooded batteries, Do not over charge very much, and Do not charge at over C/10 rate, faster charging will always shorten battery life. The discharge rate is not as critical but be prepared for low apparent capacity when fast discharge occurs. Darryl --- On Sun, 11/29/09, Conrad Geyser <conr...@cape.com> wrote: > From: Conrad Geyser <conr...@cape.com> > Subject: [RE-wrenches] concord batteries > To: "'RE-wrenches'" <re-wrenches@lists.re-wrenches.org> > Date: Sunday, November 29, 2009, 7:48 PM > > > In the vein > of us on grid folks who’s > heads spin when the off grid folks start talking about > charge programming and > gen set start up parameters… > > > > > I am > servicing an orphaned 48 V off grid > system that is only 1 1/2 years old, with 40 Concorde Sun > Extender batteries, > which are for the most part, shot (about half of them under > 10V after a generator > EQ charge). I’m sure the batteries have been > abused at least after > the point that someone lowered the generator start voltage > to 40V. We’re > still doing fact finding on the charge parameters for the > PV and wind, but I’m > wondering if there is anyone that has an opinion on the > Concorde batteries. > > > > > And at > least at this point, I’m glad > I had to study for some off grid questions on the NABCEP > test, not to mention > the conversations on this list. : > > > > > > > Conrad > > > Cotuit > Solar > > > > > > > > > > > > > > > > > > > > From: > re-wrenches-boun...@lists.re-wrenches.org > [mailto:re-wrenches-boun...@lists.re-wrenches.org] On Behalf Of Bob-O Schultze > > Sent: > Wednesday, November 25, 2009 > 9:59 AM > > To: > RE-wrenches > > Subject: Re: > [ > RE-wrenches ] Nabcep - grid tie---Off > grid > > > > > > William, > > > > Nice to meet you -however briefly- at > the Solar Zoo in > Anaheim . > > > > > > If you don't see the value in being > NABCEP certified, then you > shouldn't bother with it. If your state- as more than a > few have- decides to > recognize it in some way that affects your pocket, then > you'll likely change > your mind PDQ. I've personally gotten one or two jobs > that I know about because > I was Certified and the other bidder was not, but our bids > were very close in > price. Low-ballers, like head lice, are just a nasty fact > of life. > > > > > > While I generally agree with you on your > point #2, it varies a lot > state to state. I'm licensed in CA and OR. While I > understand the rules in CA > are changing, enforcement is, and has always been, a joke. > In OR, you need a > 4000 hour apprenticeship AND 256 hours of general > electrical classroom time to > get a Renewable Energy license. A general journeyman > license is twice that. > I've had inspectors come to our job site and check that > everyone is licensed. > In OR, you don't lay hands on a wire without a license. > Ever hear of the like > in CA? Maybe in the big cities, but nowhere > else. > > > > > > We're totally on the same page about > the IBEW. If you understand that > their goal is total domination of the electrical trade > everywhere, a lot of how > they operate makes sense. I'm a pro-Union kinda guy as > a rule, but, like > religion, too much of a thing is way worse than > none. > > > > > > As to experience with EMT and the like, > again it varies state to state > and certainly region to region. In this neck of the woods, > if you can't bend an > offset or saddle bend, you are either a new apprentice or > unemployed. > > > > > > Best, Bob-O > > > > > > > > > > > > On Nov 24, 2009, at 11:48 PM, William > Miller wrote: > > > > > > > > Friends: > > > > I'd like to make two brief points on the > training/NABCEP debate: > > > > 1. If I thought NABCEP certification would get me one more > job I'd normally > lose to a low-ball bidder, I'd be inclined to sit for > the test, but it won't. > > > > 2. Most solar electric installers could not be considered > electricians. > Until they learn the trade, they are not qualified to > install the most basic > grid tie system. Conversely, many electricians with > the most basic electrical > skills think they know all that needs to be known to design > and install > solar-electric. Wrong again. > > > > I don't support the IBEW concept of taking over the > solar industry by force, > but I do respect their concept of actually encouraging well > rounded electrician's > skills. How many solar installers can actually lay an > offset into a stick > of EMT? Not many. Most are glorified stereo > installers, plugging > and praying. > > > > Respectfully, > > > > William Miller > > > > > > > > > > > > > > > > -----Inline Attachment Follows----- > > _______________________________________________ > List sponsored by Home Power magazine > > List Address: 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 > > Check out participant bios: > www.members.re-wrenches.org > > _______________________________________________ List sponsored by Home Power magazine List Address: 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 Check out participant bios: www.members.re-wrenches.org
