Best way to measure battery degradation

[Esprit1st]

That's the question. What's the best/easiest/most accurate way to measure battery degradation on the Kona?

I guess options are:
- torque pro
- driving measuring energy used

What else? The driving method I believe is not necessarily the easiest because of regenerative breaking which will always happen in the Kona. I suppose using torque pro to note CEC and CED before the trip and after might be the best way to measure energy usage, then using SOC to determine degradation?

Any thoughts?

 

[hieronymous]

Any method would require a baseline for comparison.
Cars are fundamentally for transportation of humans and their cargo from A to B then back again, so what better measure than driven range?
Any degradation that is measurable needs also to be meaningful - if range reduction is 0.5km, does that have meaning?
Lifetime usability is defined within the constraints of the SoC construct, with unknown capacity outside of that, so degradation can only be measured relative to SoC, and takes place over years, not a trip or two ..

 

[Esprit1st]

Well of course, it obviously takes place over a long period of time. However, EVs of different manufacturers display different data so it needs to be calculated differently.

A Tesla will always show you the driving distance on the GOM according to the EPA rating, no personal driving habits calculated into the equation, so it's actually not really a GOM.

Our GOM is calculates a custom distance which will obscure any degradation.

I guess the Leaf had done kind of bar system that shows degradation. But I have no clue as how it works.

I figure for the Kona, the most accurate way is to charge to 100% and take the. CEC and CED numbers, drive for as long as possible and lowest SOC possible, then using CEC and CED again to calculate the total energy used (without Regen) vs SOC. Then do the same procedure once a year or so to determine changes in degradation. You're establishing you own baseline by checking the first time (100%).

Interestingly enough, in theory the Kona could hide degradation by expanding usable energy into the unusable part on top/bottom of the battery. I doubt that would be the case, though, since it's there to protect the battery from/minimize degradation on the first place.

 

[KiwiME]

The best I can suggest is that if the increase in CED minus 0.96 times the increase in CEC totals 64kWh while driving from 100% to 0%, then that matches the capacity advertised by Hyundai. I believe CED/CEC is about an accurate a measure of energy transfer as you going to get and CEC (charging energy) has to be factored by the battery efficiency to normalise it with delivered energy. My measurement is that it's 96% on average.

It's not certain you can extrapolate from using a portion of the SoC range because you would have to assume it linearly represents capacity and it might not.
Somewhere I recall that TP's SoH value is valid if the car is charged from under 20% to 100% but no one has seen anything under 100% yet.