Peukert's law was developed for Lead-Acid batteries, and works well in that application.
It does not necessarily apply to other battery chemistries, especially Lithium-Ion batteries. Lithium-Ion batteries tend to self-heat during rapid discharge, and the Nernst Equation predicts battery voltage will increase with temperature. Thus, the effect of increased resistance is offset by the self-heating effect. This advantage of Lithium-Ion batteries is a well-known advertised feature. In a research paper, a 50Ah lithium-ion battery tested was found to give about the same capacity at 5A and 50A; this was attributed to possible Peukert loss in capacity being countered by the increase in capacity due to the 30◦C temperature rise due to self-heating, with the conclusion that the Peukert equation is not applicable. https://www.google.com/amp/s/www.researchgate.net/publication/245106038_A_critical_review_of_using_the_Peukert_equation_for_determining_the_remaining_capacity_of_lead-acid_and_lithium-ion_batteries/amp Sent from my iPhone > On Mar 14, 2019, at 10:19 PM, Lee Hart via EV <email@example.com> wrote: > > Michael Ross via EV wrote: >> I am not sure about previous discussions and you may know this: Peukert's >> Law is not applicable to Li ion cells in any way. It only relates to lead >> acid cells. > > I agree with the rest of what you said, but not with this. Peukert's law says > nothing about the chemistry involved; it applies to *all* types of batteries > and all chemistries. > > Peukert's equation applies to any battery or cell that has internal > resistance, and that has a minimum "cutoff" voltage below which it is harmed. > It simply states that the higher the load current, the lower the apparent > amphour capacity. High currents cause a larger voltage drop, so you reach the > "cutoff" voltage before the cell is truly dead. > > The amphours are not "missing"; you just can't get them without reducing the > load current, or pulling its voltage below the safe minimum. If you're > willing to shorten the life of the cell, you can still get it. > > Peukert matters more for lead-acids because they typically have a higher > internal resistance. In particular, lead-acid internal resistance goes up a > lot as the cell approaches dead. Most other chemistries do not have this > large change in internal resistance as a function of state of charge. > > -- > Any intelligent fool can make things bigger, more complex, and more > violent. It takes a touch of genius, and a lot of courage, to move > in the opposite direction. -- Albert Einstein > -- > Lee Hart, 814 8th Ave N, Sartell MN 56377, www.sunrise-ev.com > _______________________________________________ > 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) > -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://lists.evdl.org/private.cgi/ev-evdl.org/attachments/20190315/23251fe5/attachment.html> _______________________________________________ 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)