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 <ev@lists.evdl.org> 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
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