I think it's more important to think how the user benefits from the battery sizing.
While it might sound irrational to have 150kWh onboard it would enable stressless driving with longer useful lifetime. The vehicle it self will have better resale value as it remains more usable even after 10 or 15 years. Also people need to charge their cars only as much as they use. It has nothing to do with the battery size. But... 1C charging with 20kWh pack is 333Wh/minute. 1C charging for 150kWh pack is 2.500Wh/minute. If it takes 250Wh/km (400Wh/mi) you either gain 0,83mi/minute or 6,25mi/minute. A DC-dumping with 300kW will stress less the larger pack as it has more mass to absorb the losses and there's less temperature rise during use. Also the discharge side has to be considered. You might not need more than 20kW to move one econobox but see how Model S P85D puts the EV's on the map. Our budget conversions could not do that. We need to admit that. Sorry. What makes all the difference for the business is how much does the battery cost. We will see less than $100/kWh before 2020. Or at least it is possible but if demand is high it sets the price level. On the other hand Tesla may provide Model 3 as a service and they will own the cars always. Then it does not matter how much the cells cost. You just pay that 10c/mi and nothing else. So it does not matter if it weights 2, 3 or 5 tons. Even less if the car drives itself. :) -Jukka http://www.google.com/profiles/jarviju#about 2015-09-28 23:39 GMT+03:00 Peri Hartman via EV <[email protected]>: > I think the key factor is the Cd of .16. While I think lighter vehicles > are better for many reasons, it doesn't seem to make that much difference > in efficiency unless you are spending most of your time on slow speed city > streets. > > For example, my Leaf gets about 1.5 - 2.5 miles per kWh (depending on > accessories and temperature) on city streets where I live. But if I go > 60mph on the freeway, I can sometimes get 4 miles per kWh. > > Peri > > ------ Original Message ------ > From: "Lawrence Rhodes via EV" <[email protected]> > To: "[email protected]" <[email protected]>; "[email protected]" < > [email protected]> > Sent: 28-Sep-15 1:31:45 PM > Subject: [EVDL] EVLN: The Big EV Debate> Go for Small or Big Battery Pack? > > The debate should be about light or heavy vehicles and efficiency. If >> you have an efficient vehicle that is light you might draw 55wh per mile. >> The typical heavy conversion like the I3 , Leaf, Rav4, IMEV, or any other >> of the currently available EV's are just too heavy to give good range with >> a small pack. They all draw 200 or more wh per mile. The I3 is going in >> the right direction. It has a relatively small pack and is more efficient >> than all the other competitors. If however you have a light vehicle >> around a thousand pounds your range will be close to 350 miles with a 16kw >> battery pack. The vehicle needs to have a CD of about .16. With these >> specifications you don't have to have a big pack. It will charge in 2.5 >> hours with a 6.6kw charger. Efficiency and charging time should be the >> goal. Smaller the pack the quicker the charge. Also the packs will last >> longer as they are not stressed as much by carrying large weights. >> Engineering the right combination is what is needed. Not 85kw packs in >> 5000 pound cars...however they are very comfortable and useful as is and >> better than the ICE alternative. Lawrence Rhodes >> -------------- next part -------------- >> An HTML attachment was scrubbed... >> URL: < >> http://lists.evdl.org/private.cgi/ev-evdl.org/attachments/20150928/dcb4a2f9/attachment.htm >> > >> _______________________________________________ >> UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub >> http://lists.evdl.org/listinfo.cgi/ev-evdl.org >> Read EVAngel's EV News at http://evdl.org/evln/ >> Please discuss EV drag racing at 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 > Read EVAngel's EV News at http://evdl.org/evln/ > Please discuss EV drag racing at NEDRA ( > http://groups.yahoo.com/group/NEDRA) > > -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://lists.evdl.org/private.cgi/ev-evdl.org/attachments/20150929/a3ec98fb/attachment.htm> _______________________________________________ UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub http://lists.evdl.org/listinfo.cgi/ev-evdl.org Read EVAngel's EV News at http://evdl.org/evln/ Please discuss EV drag racing at NEDRA (http://groups.yahoo.com/group/NEDRA)
