I suggest that high rate recharge could be safely done but only with a charge algorithm more sophisticated than what is commonly found in renewable energy gear.
The chargers typically found in our industry deliver the same "bulk" charge amperage from initiation of the recharge all the way to when the absorption voltage is reached. So...if you set that for a high value the same high rate would be present not only when the battery is highly depleted but also when the battery is approaching 80% state of charge. That seems scary to me. The electric vehicle industry may offer some good choices in chargers specifically for "rapid recharge". These would deliver highest amps at first but would diminish the amperage as the battery voltage ramps up--without waiting for the absorption voltage to be reached before the amperage taper begins. You might like to ask the technicians at your battery manufacturer to make sure they're OK with your intended recharge method. Regards to all, Mick Abraham, Proprietor www.abrahamsolar.com Voice: 970-731-4675 On Tue, Sep 15, 2009 at 9:11 AM, Walt Ratterman < wratter...@sunenergypower.com> wrote: > Peter, > > > > The DEKA charging manual that I have been working from for their sealed > batteries (AGM and Gel) quote 30% of C20. > > > > And….DEKA’s literature also has a maximum charging voltage of 2.35 VPC. > > > > Not sure about the other brands. > > > > Thanks, > > > > Walt > > > > *From:* re-wrenches-boun...@lists.re-wrenches.org [mailto: > re-wrenches-boun...@lists.re-wrenches.org] *On Behalf Of *Peter Parrish > *Sent:* Tuesday, September 15, 2009 7:33 AM > *To:* 'RE-wrenches' > *Subject:* [RE-wrenches] Charging AGM Batteries > > > > I have been told that AGM batteries can withstand pretty aggressive > charging rates, with a bulk rate being ½ of C/20. For example a MK 8A8D, > with a C/20 of 245 A-h, would start with 122 A. If this is okay, can I still > use the standard 14.6 V value for switching from Bulk to Absorb? What about > ambient temperature effects at high charge rates? > > > > We have need from time to time to charge AGMs as quickly as we can safely > do so, so any information on high charge rates would be appreciated. > > > > - Peter > > > > > Peter T. Parrish, Ph.D., President > California Solar Engineering, Inc. > 820 Cynthia Ave., Los Angeles, CA 90065 > CA Lic. 854779, NABCEP TM Cert. 031806-26 > peter.parr...@calsolareng.com > Ph 323-258-8883, Mobile 323-839-6108, Fax 323-258-8885 > > > > > _______________________________________________ > 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 > > >
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