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Ok EV wizards it’s time to educate the ol’ Lou-ace here. “Red Sparky” is officially on the road, that is my 1994 Mazda b2300 truck conversion, 120 volt, AMD 9’ motor, Crown GC225 (6volt) pack, Curtis 1231c charger. I’ve made a few runs now and am trying to figure out my performance. Here are my assumptions, please feel fee (as I know you guys will!!) to check them. According to Bob Brant, a depleted cell measures 1.75 volts and a nominal fully charged cell measures 2.1, therefore my swing, at 60 cells is from 105v to 126 volts. #2 if my pack is 225 amps, than a drop of 1 volt =10.75 amps, with 105v being “empty” and 126v being full. My last run ( on hilly terrain) was 13 miles and after 30” equalization I read 122.3 volts remaining before charging therefore I used 42.8 amps or 5136kwt, using these assumptions, this works out to 395wts/mi. Like I said I’m just starting to calc. my performance but this sounds too good to be true. Of course I will be tracking and trending all of my trips to get more data, but if these numbers hold than my theoretical range is 68 mi. this seems also to be too good to be true. I realize that floodies don’t like to give up their last 20% therefore 225amps really becomes 205 amps useable, and makes the theoretical range 62 miles. Am I doing any of this right ? thanks again. Ps the temp here is only 40F. and my batteries are brand new.
Hi Lou,
First, congratulations for getting on the road.
A good source for understanding batteries is There you can find State-of-Charge vs. voltage and temperature. Your ending voltage of 122.3 at 40F indicates just over a 50% SOC, so your range when driven as you did will be about 25 miles. Remember that this is Peukert effect corrected capacity, so you probably used 50 A-hr of charge.
PS study up a little so you can distinguish Amps and Amp-hr and similarly watts from watt-hours.
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