Ok guys, most of you are probably familure with my build, the 1995 Mazda truck b2300 FB 4001c motor, curtis 1231c controller, Zivan charger, 120 volt ( #20 crown GC 225 amp 6 volt batts.), 2-0 welding cable, top mount copper connectors. I now have 200 miles on various trips and am comfortable that 1: no wiring problems seem to exist, all cables and connections are cool and tight after a run. 2: the Zivan top charges to 2.75 volts per cell, and all cells measure to within 1/10th volt after charging and after a run. My original goal when I built the EV was to use it as a work vehicle ( 28 mi one way, mostly freeway, 110 v. plug available at work ), but now I realize with the lead batteries, that probably won’t work ( not at freeway speeds!!). I don’t think that I have driveline drag or brake drag. I switched the, transmission and 3rd member to 40wt synthetic motor oil. I raised the rear end and ran to 55 mph, it took about 3 seconds for the wheel to coast to stop ( this seemed a little quick, no clicking or grinding was noticed.), I also replaced/lubed the front bearings, and they turn nicely no sign of brake or other drag.
Now here’s how she runs, when I start out the amp meter will spike at 500 amps than settle down to 100-200 amps with increased rpms, this happens through out 2nd and third gears with good acceleration in 1st and 2nd, top speed in 2nd is 45 mph, but she struggles to hit 55 or 60mph. Voltages at full charge will sag to 106-110 and rebound with decreased throttle, of course the sag becomes more pronounced with less juice in the batts, probably within 5-8 miles at this point I’ve seen sags to below 100volts that usually rebound quickly after acceleration. Does this sound about right to everyone?
On the one long run that I attempted ( 30 miles round trip, mostly freeway, running hard!) it was cold ( 36 F) and windy, and the batteries were new, as I was doing the return leg my sags got lower and lower, 90-80-70v and the amps started dropping too! I pulled over at 28 miles for 5 minutes ( 2 miles from home!!), by than the batts. Had recharged enough to get home. After 2 hours my pack measured 121.8 and they hygrometered at 50%.
My last run was more optimistic! It was 55 degrees, and calm I went to town up and down many hills, and kept my speed to less than 45 mph, in 2nd gear. After I returned home, 18 miles. With good power to spare, I let the Batt. Eq. for 2 hours and they read 123.5 volts ( or 32.25% used) and hygrometered to between ½ and ¾ .
Now my math is still a little fuzzy! The battery stats are 20 AH 225, with a RC of 115” at 75 amps or 143 Ah.
So, does one use the 20ah rating or the RC in estimating usage and range? i.e.
143X .3225 =45,795 Ah used 2.54 A/ mile, .30 Kwt/mi, or
225X .3325=72.56 AH used 4.03 Amp/mi, .48 Kwt/mi and:
how does this data relate to the predicted range of my truck?
I would like to think that, using the RC rate which is load rated that I should safely be able to go 75% of 143 amps, or 107.25 Ah / 2.54/mi. = 42.22 mile range. That’s only a total usage of 12.6 Kwt. Kind of wimpy for a 27 kwt system. Is this the reality of lead batteries? And how does it differ from lipo’s? thanks to all again.