The Peukert effect is there and while the final discharge (0%) capacity is very similar, Yes the effect under these conditions is about 1.05 as you say. However the discharge curves for different discharge rate are quite different in shape and this in combination with BMS can cause the Peukert effect to apparently increase.

The cutoff point on most BMS to prevent a 0% discharge happens earlier with higher drain currents. The resulting capacity reduction can be as much as 20-30% depending on the individual cell. Battery University and have the curves which show this. If there was no BMS to protect the battery then this would not happen but the downside is the potential damage to the cell.

On 15/03/2019 03:27, Bill Dube via EV wrote:
Diffusion rates are vastly less in Li-Ion. Thus, Puekert exponents are very near unity (1.0). Yes, there is some tiny effect, but no, the Puekert equation is not really applicable.

The one hour capacity is essentially the same as the 20 hour capacity in Li-Ion.

Bill D.

On 3/15/2019 3:19 PM, Lee Hart via EV 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.

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