Ok, I've pondered the previous emails, and pulled some info off http://www.baaction.org/ev_project/batteries_1.html which seems to make sense, though there is one "mystery" number I'd like you to ponder.
First, here are some amp hour specs for Trojan 6 volt batteries: T-105 217 (20-amp hour rating) T-125 235 (20-amp hour rating) T-145 244 (20-amp hour rating) And here's the amp hour conversion factor provided by Trojan for a one-hour rating, which should be used because of the faster draw of current when the batteries are used in an EV: X hr Conversion rate factor 1 hour rate is multiplied by .57 2 .67 3 .74 4 .77 5 .82 6 .84 7 .86 8 .87 9 .89 10 .91 20 hour rate is multipled by 1.00 So, a T-105, rated at 217 amps is really able to produce .57x217=124 amps at an EV one-hour rate. 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. Now comes the mystery formula. According to the website, a Geo Metro using a DC motor will use about 200 Watt hours per mile at 60mph. This number supposedly came from a series of tests. Can anyone confirm/challenge? Anyway, if I divide 15,500 watts by 200 watts/mile, I get a range of 77.5 miles at 60 mph -- I assume this means the batteries are completly drained at the end. I know that isn't a good idea, so I'll by .80, to allow .20 left in the batteries, and get 62.24 miles on a full charge at 60mph, which seems to be in the ballpark for EVs. So, does this math look right? Now for the final question for tonight -- does all this mean that the vehicle will be using energy at the rate of 200 watts per mile at 60mph? Is that an appropriate way to look at the "fuel consumption"? In other words, once the car reaches 60mph, it theoretically takes 200 watts per hour to keep it going, assuming a flat road and no other external variables entering the picture. Is that right? As always, thanks for the help. Bruce Chapel Hill, NC "Dead fish go with the flow..." Anon.
