But even if the battery can take a high regen current, is it good for it long term? For example, Nissan recommends not to quick-charge too often. With a relatively small number of super caps, the regen spike could be distributed and recharge the battery more gently. Would that be better?
Peri -----Original Message----- From: [email protected] [mailto:[email protected]] On Behalf Of Willie2 Sent: 14 November, 2013 7:42 AM To: Electric Vehicle Discussion List Subject: Re: [EVDL] EVLN: Graphene Supercapacitors Ready For EVs On 11/13/2013 11:25 AM, EVDL Administrator wrote: > On 13 Nov 2013 at 3:33, brucedp5 wrote: > >> Conventional batteries take so long to charge that they cannot efficiently >> store braking energy. > Hold on there! A lead-acid battery can be charged at thousands of amps if > it's below 80% SOC. > > To view it from another angle, a battery can usually charge as fast as it > can discharge. I'm sure there are exceptions, but in my experience, most > drivers seldom decelerate dramatically faster than they accelerate. > > That said, supercaps have been shown to be useful in mitigating peak > currents on discharging, and maybe this would help too on charging. But I > suspect that further battery refinement - and the extra cost of the caps - > will make this a moot point. I also noticed the poor quality of the article also and intended to comment on it at the time. I guess he is thinking of not BEVs but hybrids with relatively small batteries. As far as I know, ALL BEVs with regen capture an acceptable amount of braking energy. A Tesla S (warm with a not full battery) can regen at 60kw; that covers probably more than 90% of braking needs. I have no personal experience, but I suspect even the small battery in a Volt allows an acceptable job of regen. > _______________________________________________ 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)
