Ben Apollonio wrote:
With all due respect to Lee and his expertise in so many areas, I believe this is incorrect. Lithium Ion has a nearly unity coulometric charge/discharge efficiency. Although high discharge rates depress the voltage more, and therefore cause your battery to reach "empty" sooner, you haven't actually depleted a greater number of amp-hours.
I agree, and tried to explain this more fully with my "sponge" analogy.
1.0 is the correct number if you want accurate SoC representation
The E-meter/Link-10 shows you true amphours regardless of the Peukert setting. Peukert is only used for the empty-full "fuel gauge" LEDs at the top. Setting the correct value for the Peukert exponent and capacity allows the fuel gauge to accurately reflect that higher currents makes the battery reach its minimum voltage cutoff point sooner.
IMO, a better approach would be to simply get to know what your battery's ESR is at various temperatures and SoC.
Except that it changes too much between batteries, over time, at different temperatures and states of charge, etc.
The whole point of the Peukert business is to give you a more accurate "fuel" gauge than simply watching amphours or voltage. Suppose you can drive 60 miles in 2 hours (30 mph average), or 30 miles in 1/2 hour (60 mph average) before you hit your battery's minimum voltage. Then you pick Peukert so the empty-full "fuel" gauge reaches "empty" at the end of both drives.
-- The storage battery is one of those peculiar things which appeals to the imagination, and no more perfect thing could be desired by stock swindlers. Just as soon as a man gets working on the secondary battery, it brings out his latent capacity for lying. -- Thomas A. Edison -- Lee Hart's EV projects are at http://www.sunrise-ev.com/LeesEVs.htm _______________________________________________ UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub http://lists.evdl.org/listinfo.cgi/ev-evdl.org For EV drag racing discussion, please use NEDRA (http://groups.yahoo.com/group/NEDRA)
