Thanks Lee. Dennis
-----Original Message----- From: [email protected] [mailto:[email protected]] On Behalf Of Lee Hart Sent: Wednesday, May 07, 2014 1:37 PM To: Electric Vehicle Discussion List Subject: Re: [EVDL] Peukert # with Lithium Batteries Pestka, Dennis J wrote: > So let me ask another question. > > Using this E-Meter to track the state of my pack, am I better to watch: > - Kwhr's used > - Ahr's used > - % Remaining > - Voltage at state of rest. > - Something else ? When you don't know much about the pack, I would watch voltage under load. I'd set the battery capacity to about 80% of what it is advertised to be. Set the E-meter/Link-10 low battery alarm for something conservative like 2.75v per cell. If you have a BMS, then it should also provide a warning when any cell drops to some low voltage cutoff. On charge, I'd set the E-meter/Link-10 for a CEF of 0.99. Depending on how much current your BMS uses for balancing, you may have to change the CEF to get it to reset to "full" at the end of a charge cycle. I'd start with Peukert set to 1.1. If the empty-full lights indicate "empty" before the low voltage alarm, decrease the Peukert value. If you reach the low voltage alarm before the empty-full lights show empty, then increase the Peukert exponent. You can set all of these more accurately with measurements, of course. The whole point is to find a set of values that accurately estimates your battery capacity, at either high or low currents. -- Ring the bells that still can ring Forget your perfect offering There is a crack in everything That's how the light gets in. -- Leonard Cohen, from "Anthem" -- 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) _______________________________________________ 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)
