Hi Mac, We fabricated and operate a similar sized (400 kWh) battery / inverter / generator hybrid system for BC Hydro, our power utility servicing a remote community. It has been online for 2 years now. Using Dekka / East Penn D-series batteries which we had custom built to our specs. A notable difference is we have 100 kW diesels and 60 kW inverter capacity in a 120/208 SMA inverter config (stepped up to 14.4 kV distribution). The system works really well and it currently 100% uptime for last 12 months. This is an unattended system we are onsite to maintain every 2 months. No renewable input at this time. The sizing you have reported seems out of ratio. ~ 20 kW of charging power into a 400 kWh battery bank ie C/5. Depending on the loads the gen is carrying along with charging that could further reduce available charge capacity. That generator is going to have to run for a very long time to charge that battery. We call this the big battery blunder syndrome - which has caused many failures of such scale of system. Kevin
-----Original Message----- From: [email protected] [mailto:[email protected]]On Behalf Of Mac Lewis Sent: March 11, 2014 7:27 AM To: RE-wrenches Subject: Re: [RE-wrenches] Huge battery bank recommendation To clarify, this is for an off-grid application, 4 Sunny Islands, 30kW generator. On Tue, Mar 11, 2014 at 9:16 AM, August Goers < [email protected]> wrote: Mac, Is this for an off grid system? We're doing our first project with a Deka Unigy II battery system but they are AGM and I believe only good for grid tied battery backup or applications where you won't have a very deep depth of discharge: http://www.dekabatteries.com/assets/base/0919c.pdf Best, August August Goers Principal Luminalt Energy Corporation o: 415.641.4000 m: 415.559.1525 www.luminalt.com On Tue, Mar 11, 2014 at 6:24 AM, Mac Lewis < [email protected]> wrote: Hi wrenches, I am consulting on a job that requires an 8000 Ahr battery bank. This is quite a bit beyond my normal battery bank realm. What would you recommend for this? Thanks in advance -- Mac Lewis "Yo solo sé que no sé nada." -Sócrates _______________________________________________ List sponsored by Home Power magazine List Address: [email protected] Change email address & 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] Change email address & 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 -- Mac Lewis "Yo solo sé que no sé nada." -Sócrates
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