Dan,
I concur with your basic assessment. After listening to an Aquion presentation, and reviewing the operating curves, this battery has a very narrow application. Most off-grid houses these days have significant surge loads. That is why we spend so much time and effort making sure our inverter is properly rated for the worst-case surges. Most batteries are relied upon, not just for energy storage, which Aquion appears to deliver, but we also must have significant surge power. Aquion essentially has no surge capability. If you have an application where a non-surge inverter will work, then you might have an Aquion application. Otherwise, stay away from Aquion until they develop a concept that allows surges. Think of the Aquion battery like a fuel cell. Fuel cells are notoriously poor at surges. Bill. Bill Brooks, PE Principal Brooks Engineering From: RE-wrenches [mailto:re-wrenches-boun...@lists.re-wrenches.org] On Behalf Of Dan Fink Sent: Friday, January 29, 2016 10:52 AM To: RE-wrenches <re-wrenches@lists.re-wrenches.org> Subject: Re: [RE-wrenches] Aquion Batteries I second Larry's concerns about Aquion's SOC/voltage curves and tripping LVD at only 40% DOD with standard PV equipment, tied in with not being able to handle high discharge C-rates and surge loads. I did some math on running a typical off-grid home with a well pump on Aquions, and it wasn't pretty, but I may not have done the math right. Very interested to hear personal experience on off-grid homes with these batteries. I was starting to envision applications for remote MET tower, repeater tower etc applications with low discharge C-rates and high charging C-rates, and then saw Aquions lowest operation temperature of -5C, 23 F. That's considered a "heat wave" during certain times of year in many areas, including here in sunny Colorado. In these applications the batteries are NOT in a heated room, instead an outdoor enclosure at the base of a tower. AGMs are serving us here just fine on these sorts of esoteric installations, and they have no problem with -29C and lower when kept at high SOC. And, cheap, easy to replace, and giving us many years of life. The ROI math on the Aquions compared to AGM is not adding up for me on these applications. My only experience with Aquion was their class at the NABCEP conference last year. Any ground truth experience and stories on Aquions and other similar technologies appreciated here also. Best regards; Dan Fink Adjunct Professor, Ecotech Institute IREC Certified Instructor™ for: ~ PV Installation Professional ~ Small Wind Installer Executive Director, Buckville Energy NABCEP Accredited Continuing Education Providers™ <tel:970.672.4342> 970.672.4342 On Fri, Jan 29, 2016 at 7:55 AM, Starlight Solar Power Systems <la...@starlightsolar.com <mailto:la...@starlightsolar.com> > wrote: I too am interested in anyone that has installed these. I had some concerns back on Nov 10, 2014. Here is a copy/past from that conversation: Something does not add up to me. The cell has a voltage discharge curve way outside that of RE equipment, 1.75 Vpc down to 0.5Vpc. I can't see how this technology could be scaled to RE applications without wasting much of the capacity. From what I see, only about 40% could be used before LVD. And this: The Aquion battery claims their 2.4kWh, 48 volt stack operates from 59 to 30 volts. Many inverters have a LBCO of 1.75 Vpc (42 volts). Depending on voltage sag, that means about half of the capacity of the Aquion battery can't be used. Even if the outback can operate down to 1.5 Vpc, you are still not able to use the full capacity of the battery unless your load is less than 800 Watts. I have reviewed their technical presentation and it looks to me like the capacity simply can't be used in the off grid environment. If you can't use it, why do they rate it at 2.4kWh? BTW, the Voltage vs.Energy chart on the spec sheet does not match the first chart I posted. On Jan 29, 2016, at 7:30 AM, Chris Schaefer <ch...@solarandwindfx.com <mailto:ch...@solarandwindfx.com> > wrote: To All, Great insight on the lithium movement. I do am looking for anyone dealing with the new Aquion batteries. I’ve got a couple of potential clients that have inquired about them. Saw them at a NABCEP training session last spring and while the idea is moving I wasn’t impressed. Perhaps it’s time to start a new thread, “Aquion batteries”. Thanks, Christopher From: RE-wrenches [mailto:re-wrenches-boun...@lists.re-wrenches.org] On Behalf Of d...@energysolarnow.com <mailto:d...@energysolarnow.com> Sent: Friday, 29 January, 2016 00:49 To: Dan Fink Cc: re-wrenches@lists.re-wrenches.org <mailto:re-wrenches@lists.re-wrenches.org> Subject: Re: [RE-wrenches] LiFePO4; WAS Availability of Powerwall Batteries Thanks for sharing your experience with these batteries, Dan. I have similar SOC issues with an off-grid customer who has the Aquion Hybrid Ion batteries. It has difficulty reaching full charge from solar, requiring the genny to kick on each morning even in the summer. This is even worse in cold winter weather. Your explanation of the change in Peukert's exponent above 80% SOC with NiFe batteries sounds like what is happening here as well. Do you have any experience with Aquion batteries that you can share? Thanks Don Barch Energy Solar d...@energysolarnow.com <mailto:d...@energysolarnow.com> _______________________________________________ List sponsored by Redwood Alliance List Address: RE-wrenches@lists.re-wrenches.org <mailto:RE-wrenches@lists.re-wrenches.org> Change listserver email address & settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://www.mail-archive.com/re-wrenches@lists.re-wrenches.org/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>
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