Huh? Wow... Remember, we are talking about ENERGY, not the cost of the battery. It seems crazy to me that one would invest tens of thousands of dollars in a SOLAR energy production system, and be happy then with throwing away 50% right off the top in a poor efficiency battery system just to save a few dollars in battery cost. (Given that a battery is a wasted investment anyway as far as energy production is concerned compared to grid-tie).
Although this is an EV list, where efficiency of batteries is not of top priority (maximum capacity is), be careful trying to carry that experience over to solar energy systems, where efficiency (getting the most energy at the highest value) with the least waste is the priority. That's why the 100% storage efficiency of the grid, with unlimited capacity and at zero cost* beats battery storage 10,000 to one (see the earlier numbers). *plus the minimum account charge ($8/mo in Maryland). Bob, WB4APR -----Original Message----- From: Ben Goren [mailto:b...@trumpetpower.com] Sent: Tuesday, December 23, 2014 4:29 PM To: Robert Bruninga; Electric Vehicle Discussion List Subject: Re: [EVDL] OT: batteries for solar PV off-grid On Dec 23, 2014, at 2:21 PM, Robert Bruninga via EV <ev@lists.evdl.org> wrote: > Giving them terrible efficiency. That's almost 50%. Given that an > electron-in to charge at 70 volts comes out at 36 volts is a 50% loss of > "power" and hence efficiency. Such batteries are great for standby back > up systems where efficiency is of no concern. But for a daily solar > cycle, adds another 50% loss factor on top of an already abisymal 30% > performance per dollar. If battery A has half the efficiency of battery B, but battery A has a service lifetime of a century and battery B only has a service lifetime of several years, it's battery B with the abysmal performance per dollar. Unless, of course, battery B costs a tiny fraction of battery A, especially if battery C with superior performance to either A or B is expected to appear on the market by the end of battery B's lifetime. b& _______________________________________________ UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub http://lists.evdl.org/listinfo.cgi/ev-evdl.org For EV drag racing discussion, please use NEDRA (http://groups.yahoo.com/group/NEDRA)
