On Jul 25, 2014, at 3:21 PM, Cor van de Water via EV <ev@lists.evdl.org> wrote:
> Why on the world would you need over 200kW unless you are doing a race > car? Well, each AC-51 is rated for ~80 kW; I'm assuming a pair is ~160 kW -- which is about the same as the 260 motor in the car already. Seemed to me that that it doesn't make sense to have the motor(s) wanting more electricity than the batteries can deliver, so I've been trying to reach at least 180 kW...but maybe that's not the way I should approach this? Um...maybe I should back up again. The only practical place to add an electric motor is along the driveshaft, after the transmission and before the differential -- which means a direct-drive setup. It's my understanding that that means lots of electric motor to be able to live with the gear ratios, with a pair of AC-51s or WarP 9s as the likely candidates. Based on that, I assumed that the batteries would, in turn, have to supply as much electricity as the motors could take -- else there wouldn't be a need for so much motor in the first place. > My suggestion: use half your pack size (are there 90 Ah cells that you > can use instead of 3 strings of 60?) which gievs half the cost and > capacity, as you indicated that is what you need. See, this is why I'm bugging y'all. As many times I've been over the various pages, I've often been looking for something different each time, and I've apparently missed something yet again. <sigh /> No 90 Ah cells are leaping out at me with a quick search, but I now see CALB 70 Ah 10C cells for $80.40 here: http://www.electriccarpartscompany.com/70Ah-32V-10C-br-SE70AHA-br-CALB-EV-Lithium-LiFePO4-Prismatic-Cell-Batteries-br-USA-or-China-Stock-br-44L-24W-81H-in-br-113-60-206-mm-br-55-lbs-25-kg_p_287.html Two strings of 45 gets 200 kW with 20 kWh at 500 pounds for $3900 -- something *much* more reasonable than anything I had calculated earlier. So...maybe this isn't hopeless after all. Thanks! ...and now back to do yet still even more research.... 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/20140725/d0b9bf98/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)
