Thanks, Michael, Peter, and Cor. Your explanations are perfect. Now to do some more math and more research....
b& On Jul 24, 2014, at 3:12 PM, Cor van de Water via EV <ev@lists.evdl.org> wrote: > Ben, > Are you putting the cells in series or in parallel? > 45 cells in parallel will indeed allow you to draw 45 times as much > current - but at the same voltage as a single cell (3.2V) 3600A still > gives 11kW. > > If yo uare putting the cells in series, then each cell can only do as > much currrent as a single cell and since all cells are stacked, that > current runs through *all* the cells, so the same 80A through them all, > but at 45 times the voltage of a single cell, so the same 11kW. > It is real simple - each cell contributes a certain amount of power: > 3.2V x 80A = 256W. > So, 45 cells can do 45 times as much power: 45 x 256W = 11.5kW > Depending how you wire those cells, they can increase the total voltage > by stacking cells in series, or they can increase the current by wiring > them in parallel, you can even create a mix of series/parallel, for > example > 3 strings of 15 series cells for 15 times higher voltage (48V) and 3 > times higher current by adding up the currents through the 3 parallel > strings for a total of 3x80A = 240A. 48V x 240A = 11.5kW because the > power can never > be more than the sum of what each cell can deliver... > > Hope this clarifies, > > Cor van de Water > Chief Scientist > Proxim Wireless Corporation http://www.proxim.com > Email: cwa...@proxim.com Private: http://www.cvandewater.info > Skype: cor_van_de_water Tel: +1 408 383 7626 > > > -----Original Message----- > From: EV [mailto:ev-boun...@lists.evdl.org] On Behalf Of Ben Goren via > EV > Sent: Thursday, July 24, 2014 2:38 PM > To: Electric Vehicle Discussion List > Subject: Re: [EVDL] How crazy am I? > > On Jul 22, 2014, at 8:21 AM, EVDL Administrator via EV > <ev@lists.evdl.org> wrote: > >> For example, the CALB 40ah cells I mentioned are rated for a maximum >> discharge of 2C (80 amps). At 144v, 80a is 11.5kW. Allowing for > losses, >> that's only about 12hp from your motor! > > I think I may be a bit confused. > > If a single 40 Ah cell can provide 80 A (for a little while), shouldn't > 45 of those 40 Ah cells be able to provide 80 A * 45 = 3600 A? That 80 A > would be at 3.2 V for 256 W. All 45 cells would be at 144 V, for 518.4 > kW or ~ 500 hp. That's three times the power of the 260 Windsor engine > in the car today, and substantially more than you're going to get in a > stock muscle car of any era -- and waaaaay more than even a pair of > AC-50s or WarP 9s is rated for. > > So...does discharge scale with the number of batteries, or is it limited > by the discharge of a single cell? If the former, I should be more than > fine with a 45-cell pack of CALB 40 Ah batteries or equivalent. If the > latter...I'm likely screwed.... > > Thanks, > > b& > -------------- next part -------------- > A non-text attachment was scrubbed... > Name: signature.asc > Type: application/pgp-signature > Size: 801 bytes > Desc: Message signed with OpenPGP using GPGMail > URL: > <http://lists.evdl.org/private.cgi/ev-evdl.org/attachments/20140724/f9e0 > 34e8/attachment.pgp> > _______________________________________________ > 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) > > _______________________________________________ > 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) > -------------- next part -------------- A non-text attachment was scrubbed... Name: signature.asc Type: application/pgp-signature Size: 801 bytes Desc: Message signed with OpenPGP using GPGMail URL: <http://lists.evdl.org/private.cgi/ev-evdl.org/attachments/20140724/d8b3b1f3/attachment.pgp> _______________________________________________ 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)
