EVDL Administrator wrote:
Unless you plan to disconnect and reconnect every single cell every time you charge, which would be pretty tedious, you'd need a contactor for each cell, one that's capable of handling full driving current. For a ~140v battery, that's 40 contactors!
Well, you could use the method that Bob Schneeviess used in his "Sno White" EV race car. The batteries were placed in regular battery boxes. There was *no wiring* to the cells!
The hinged cover of this box had spring contacts. When closed, they connected all the batteries in series for driving.
For charging, he had a *different* hinged cover that connected the batteries in a different arrangement. For lithiums, you could connect them all in parallel if you like, and charge them all with a 3.6v 500 amp supply. :-) That would automatically keep them balanced.
Such an arrangement also makes it trivially easy to replace batteries. Schneeveiss did it so his pit crew could quickly replace batteries during pit stops during a race.
-- ICEs have the same problem as lightbulbs. Why innovate and make better ones when the current ones burn out often enough to keep you in business? -- Hunter Cressall -- Lee Hart's EV projects are at http://www.sunrise-ev.com/projects.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)
