Hi Dave, We've been doing some work in this field - all of which is preliminary at this time. By no means would I consider myself an expert but a few things I have garnered over the past couple of years.
1) Most Iron Phosphate (jelly roll or prismatic) are relatively low capacity resulting in lots of cells to generate meaningful capacity. 2) Nickel Magnesium Cobalt (NMC) provides a more stable platform (less temp rise) and significantly higher capacity per cell. This allows for fewer cells resulting in easier monitoring and management of each cell. 3) To echo everyone else BMS is the key to success however, this gets increasingly more difficult if you have 100's of cells. 4) NMC technology is retailing for ~$1800 kwh or ~60k for a 700AH, 48VDC system (includes BMS). Regards, Jamie >>> "Dave Palumbo" <[email protected]> 8/21/2011 10:14 PM >>> We have a potential client for a net metered PV with battery backup system with a serious interest in using lithium ion storage batteries. I do not know of any systems that have used these batteries yet. From some quick calcs I come up with 105 LiFEYPo4 3.2 volt cells. 7 strings of 15 cells for 700 AH at 48 volts. Price is quoted at $ 125 per cell. Here’s a link the client forwarded from his research. http://currentevtech.com/Lithium-Batteries/Thundersky/Thundersky-40ah-cell-p24.html What are the reasons why these are not being used in home power systems? The web site states 3,000 cycles at 80% DOD vs. 750 cycles for typical gel storage batteries. Also, what are your favorite inverter(s) for grid tied with battery backup? David Palumbo Independent Power LLC 462 Solar Way Drive Hyde Park, VT 05655 www.independentpowerllc.com NABCEP Certified PV Installer Vermont Solar Partner 23 Years Experience, (802) 888-7194 This message contained an attachment [] that can be retrieved by visiting https://surrette.messagescreen.com/quarantine/GetAttachment?CID=81&OID=c67ea9538629411eb9ce1133c5edb36f1. Your attachment has been This email and its attachments have been scanned by iConnection E-Mail Firewall for viruses, spam, and malicious content. The information transmitted in this email is intended only for the entity or person to which it is addressed and may contain confidential/privileged material. If you received this in error, please contact the sender and delete the material from any computer. Any review, retransmission, dissemination, or other use of this information by persons or entities other than the intended recipient is strictly prohibited. %^^%
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