Steve Heath wrote: > The best mile/Kw I have got has been 180 and the worst is 230. Average > is 190 and this measurement is based on coulomb counting over the > distance.
I think you are meaning to state 180-230 Wh/mi? 180-230 mile/kWh would be extremely unusual efficiency for an on-road EV, and mile/kW just doesn’t make any sense ;^> > If I use the capacity used based on voltage then it can get very silly. > I was getting figures of 600-700 w/mile because the voltage vs soc is > non linear. I could drive 25% of the range and the capacity would drop > to 50%. This did not make sense so I stopped using them and fitted > coulomb counters. I do use the voltage to predict low battery but the > rest of the data is just a rough guide. The gauge does look pretty on > the dash though. I understand your reasoning for not using battery voltage to estimate state of charge, but when you quote any efficiency values involving Wh or kWh (Wh/mi or mi/kWh), you are, of course, taking battery voltage into account because power depends upon both the battery voltage and current, and so, therefore, does energy in Wh or kWh. Pure coulomb-counting will only give you energy usage in mi/Ah, which may be useful in the context of your own EV, but does not allow comparison to the usage of other EVs. Cheers, Roger. _______________________________________________ UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub http://lists.evdl.org/listinfo.cgi/ev-evdl.org Please discuss EV drag racing at NEDRA (http://groups.yahoo.com/group/NEDRA)
