Peter, AGM batteries account for over 50% of our battery sales. One of the beautiful aspects of AGM's is that you can hammer them very hard during the initial bulk charge stage. Their low impedance makes this easy to do. More than likely you can't make enough current to come close to the maximum in-rush this battery can handle. As long as you control voltage, hit with ALL you can! Don't try this with flooded batteries, though.
For complete details, download the technical manual from the Sun Xtender website and see section 5.4: http://www.sunxtender.com/pdfs/Sun_Xtender_Battery_Technical_Manual.pdf Man I love AGM's. Larry Crutcher Starlight Solar Power Systems www.starlightsolar.com 928-342-9103 Store and Shipping Address: 2998 Shari Ave. Yuma, AZ 85365 Mailing Address: 11881 S Fortuna Road, #210 Yuma, AZ 85367 ----- Original Message ----- From: "Peter Parrish" <[email protected]> To: <[email protected]>; "'RE-wrenches'" <[email protected]> Sent: Sunday, February 27, 2011 1:35 PM Subject: [RE-wrenches] Bulk Chrging Rate for AGM Batteries We have a portable "demo-off grid" system (24 Vdc, 120 Vac, 1kW-ac) and occasionally we end the day with a fairly deep discharge 11.6-11.7 V (80% DoD). I like to get a deeply discharged battery back up to 100% capacity as soon as possible (as opposed to letting the 850 W PV / charge controller system charge it up over a several days) and I have a AC battery chargers with "20A', "10A" and "2A" bulk settings along with being able to choose, "wet", "gel" and "AGM" settings. Our battery of choice is a SunXtender AGM battery (PVX-2120L, 12V 253 amp-hr (C/120). My question: Starting with this battery at say 11.6 volts (open circuit), is it safe to begin the bulk charge at ~8% of its C/120 capacity (i.e. 20A), and let the charger go into absorption at 14.4 V (with temperature correction of course) and finish at 2A? How high could I safely start the bulk charge? Peter T. Parrish, Ph.D., President California Solar Engineering, Inc. 820 Cynthia Ave., Los Angeles, CA 90065 CA Lic. 854779, NABCEP Cert. 031806-26 [email protected] Ph 323-258-8883, Mobile 323-839-6108, Fax 323-258-8885 _______________________________________________ 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 _______________________________________________ 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
