On May 14, 2015, at 10:47 AM, Ben Goren via EV <ev@lists.evdl.org> wrote:
> dump pack Thinking this through a bit more...I'm not sure that it would make sense for a rapid-charging station to operate without a substantial dump pack of its own. Without one, you're left needing a grid connection able to meet your peak demand, which will be truly insane. Imagine a not-too-distant future where luxury EVs come with 100 kWh packs that people expect to charge in ten minutes; that's over half a megawatt. Now imagine a convoy of such traveling together on a road trip, all of them simultaneously pulling up to each of the 36 slots in the station. No way is that station going to have a 20 MW feed from the grid...that's about 5% - 20% of the output of a utility-scale generating unit. And even the utilities themselves would have problems running such a facility because of the sharply peaking nature of the load. But if, on average over the course of a day including times when all slots are empty, the station only "sees" one or two stalls in use at a time...well, a megawatt utility connection is still pretty freakin' huge -- 1 kV @ 1 kA, or however you want to balance the two -- but much more manageable. You'd keep a constant rate (or, perhaps, varying per utility feedback but averaged to a constant) of charge going into your massive dump pack, and each of the slots would feed from the dump pack, rapidly depleting it for just a short period of time as the grid constantly trickle-fills it back up again. Again...the scale of such operations pretty much demands that they be insanely expensive, especially compared against a 110V / 15A overnight charge that'll more than satisfy almost all of almost everybody's needs once vehicles can reliably get over 200 miles on a full charge. 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/20150514/b3cbd469/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)
