Seems this 200 ah pack could put out 500 amps. The idea to extend life and reliability would be to reduce the top amp draw maybe down to 200 amps. I'm not a racer so I'm not going to miss tire shredding performance. One charger/regulator per module. Charging at a rate designed for long life. It will be doable. If worse comes to worse more cells and more limiting. Lawrence Rhodes.
>________________________________ > From: Lee Hart <[email protected]> >To: Lawrence Rhodes <[email protected]> >Sent: Tuesday, September 3, 2013 10:53 AM >Subject: Re: [EVDL] Questions about Lithium batts for a VERY light car-- under >600 lb w/o batteries > > >Lawrence Rhodes wrote: >> Thanks for the clarification. However spot welded packs have an >> advantage. I'm very interested in doing one. Seems the voltage and >> capacity of each cell must be identical when the module is put together. > >The big advantage is their higher power and energy density. A lighter and >smaller pack for the same acceleration and range. But the cells are more >dangerous in case of failures or errors, and don't have as long a life. It's >hard to find laptop cells over 3 years old that are any good. > >> Tesla is using them so a spot welder is in my future. > >Yes, they are. But they also go to heroic measures to make it work. The BMS >probably costs as much as the cells. > >The NEDRA drag racers are also using pack with many small cells. They too go >to great lengths to make it work. In their case, it only has to work for one >1/4-mile race at a time. > >So you can certainly make this method work. But it is not cheap, nor for the >inexperienced, or the faint of heart. > >-- A designer knows he has achieved perfection not when there is >nothing left to add, but when there is nothing left to take away. > -- Antoine de Saint Exupery >-- >Lee A. Hart, http://www.sunrise-ev.com/LeesEVs.htm > > > -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://lists.evdl.org/private.cgi/ev-evdl.org/attachments/20130903/bc464e8a/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)
