LFP have a flatter voltage WRT SOC than other chemistries, but others are similar just the same. On Feb 25, 2016 9:44 PM, "Michael Ross" <[email protected]> wrote:
> My experience with LiFePO4 is they only show a sag when they are near the > low cut off. Pushing them lower would be a asking for trouble if they are > not well balanced at the bottom. > > I personally think you should stop doing that. At least be sure they are > well balanced at low voltages. > On Feb 25, 2016 9:15 PM, "Craig M. via EV" <[email protected]> wrote: > >> >> I need some feedback for anyone who has seen the following effects. >> >> I want the maximum possible range out of my EV but when the battery is >> weak (58 miles or so,) acceleration can be a problem. If I hold down the >> accelerator pedal too long the voltage drops low. The motor pulls a lot of >> current, and the motor may slow down as the battery rapidly discharges. I >> have also observed that if the motor stalls, it draws very high current and >> the battery is soon fully discharged. To get home on a weak battery I have >> had to accelerate in steps or pulses. I would lift my foot off the pedal >> for about a second and let the voltage on the battery come back up before >> pressing the pedal down again to accelerate. There is an alarm that sounds >> if the voltage on any cell is too low or too high. I have an AC-50 motor >> and controller with the regenerative feature and LIFEPO4 cells. This may >> be playing a role in this effect. I would appreciate hearing from anyone >> who has pondered the effects of voltage sag on batteries and motors. I >> have asked this same que >> stion elsewhere and I got back shrieks of how I am breaking the laws of >> physics, motion or thermodynamics. I can't break those laws so I frankly >> have stopped worrying about it. I am making observations and trying to >> learn from them. >> -------------- next part -------------- >> An HTML attachment was scrubbed... >> URL: < >> http://lists.evdl.org/private.cgi/ev-evdl.org/attachments/20160225/af92877b/attachment.htm >> > >> _______________________________________________ >> UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub >> http://lists.evdl.org/listinfo.cgi/ev-evdl.org >> Read EVAngel's EV News at http://evdl.org/evln/ >> Please discuss EV drag racing at NEDRA ( >> http://groups.yahoo.com/group/NEDRA) >> >> -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://lists.evdl.org/private.cgi/ev-evdl.org/attachments/20160226/a177006a/attachment.htm> _______________________________________________ UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub http://lists.evdl.org/listinfo.cgi/ev-evdl.org Read EVAngel's EV News at http://evdl.org/evln/ Please discuss EV drag racing at NEDRA (http://groups.yahoo.com/group/NEDRA)
