It's never zero because of conservation of energy. I think Tesla says their electronics are only 80% efficient so you loose 20% on acceleration and another 20% on regen.
Not counting other losses such as wind. ________________________________ From: Michael Ross via EV <[email protected]> To: Robert Bruninga <[email protected]>; Electric Vehicle Discussion List <[email protected]> Sent: Thursday, November 6, 2014 10:10 AM Subject: Re: [EVDL] Range vs Speed I should have graphed it out for myself as a reminder. When you accelerate to speed up, the work done (velocity is changed) is in one "direction,"and when you slow down in the other. You sum positive and negative acceleration, and when you have stopped the sum is zero. But the differences in acceleration do make difference when regen and wind are considered. More likely you slow down harder than you speed up, and at lower wind speeds, with some fractional recovery from regen. De-accelerating is actually enhanced at higher speeds by air drag, but regen loses out when the wind does the work. I wonder if you regen hard from high speeds - to beat the wind to the punch, then take it easy for the slower de-acceleration, at lower wind speeds, what that does? On Thu, Nov 6, 2014 at 8:49 AM, Robert Bruninga via EV <[email protected]> wrote: > Energy used in driving is simple physics: > > Everything you put into acceleration you get back in Momentum. > Everything you put into a hill, you get back as potential energy. > Everything you put into braking is LOST (regen gains some back). > Wind resistance goes up as the cube of speed. > > So the only real control you have over energy is keeping the speed (wind > resistance) down. > > Gas cars are actually MORE efficient at high acceleration when the > throttle plate is wide open and the pumping losses are minimized. So > creeping away from a traffic light does not really gain anything. BUT, if > it is a typical gas car and the engine then keeps running during the coast > phase, that too is 100% waste (engine running but doing nothing). > > When people say go "light on the accelerator" they are not talking about > the rate of acceleration at all. They are talking about DON'T OVER > ACCELERATE beyond what it takes to coast to the next stop without having > to use the brakes. > > Bob, WB4APR > > -----Original Message----- > From: EV [mailto:[email protected]] On Behalf Of John Lussmyer via > EV > Sent: Thursday, November 06, 2014 12:44 AM > To: Electric Vehicle Discussion List > Subject: [EVDL] Range vs Speed > > I'm not seeing much difference in power usage at different speeds. > Last night, I drove 60 miles on the highway/freeway, almost entirely at > 60mph. > used 125AH out of my freshly charged pack. > Tonight, I drove the return trip, taking almost an hour longer due to > horrible slow traffic on the freeway. Often stopped or below 10mph. > Same power usage. > > -- > Tigers prowl and Dragons soar in my dreams... > _______________________________________________ > 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) > > -- Put this question to yourself: should I use everyone else to attain happiness, or should I help others gain happiness? *Dalai Lama * Tell me what it is you plan to do With your one wild and precious life? Mary Oliver, "The summer day." To invent, you need a good imagination and a pile of junk. Thomas A. Edison <http://www.brainyquote.com/quotes/quotes/t/thomasaed125362.html> A public-opinion poll is no substitute for thought. *Warren Buffet* Michael E. Ross (919) 550-2430 Land (919) 576-0824 <https://www.google.com/voice/b/0?pli=1#phones> Google Phone (919) 631-1451 Cell (919) 513-0418 Desk [email protected] <[email protected]> -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://lists.evdl.org/private.cgi/ev-evdl.org/attachments/20141106/c07ac7ee/attachment.htm> _______________________________________________ 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 -------------- An HTML attachment was scrubbed... URL: <http://lists.evdl.org/private.cgi/ev-evdl.org/attachments/20141106/ecee185a/attachment.htm> _______________________________________________ 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)
