We were talking about a constant current draw. By definition a lead-acid cell is empty (at a given current) when it's voltage drops to 1.75V. A 120V (nominal) pack has 60 cells so, when used at a constant current, it is empty when it reaches 105V.
Thomas Shay wrote: >----- Original Message ----- >From: "Peter VanDerWal" <[EMAIL PROTECTED]> >To: <[EMAIL PROTECTED]> >Sent: Tuesday, September 03, 2002 9:17 PM >Subject: Re: EV Newbie -- 3 > > >>> >>>So, if I have a 120 volt battery pack of T-105s, I multiple 120x124 and >>> >get > >>>15,500 watts, or 15.5kW (VxA=W) of power on a fully charged battery pack. >>> >>Sort of. The pack voltage will sag under that kind of current, drop >>continuously -though slowly- until it gets down to 105V at which point >>the pack is empty (by definition a 120V pack is empty when it reaches >>105V). >> > >A 120 volt pack isn't empty when its voltage drops to 105. There's >nothing sacred about 105 volts. A conservative driver wanting to >be kind to his batteries would do well to avoid frequent drops >below 105. A less conservative but still reasonable limit is 90 volts >for short bursts of acceleration or hill climbing. A 120 volt pack that >can't maintain 105 volts at 400 amps can still go a considerable >distance if the current drain is reduced or if the pack is given a rest. >Unlike a tank of gasoline, a battery pack doesn't suddenly go >empty. > >Tom Shay > > >
