Yes, it does.Aakee, I’m a little confused by your graphs and conclusions. According to the first graph, it looks like keeping the battery below 55% helps with calendar aging.
We need to understand the magnitudes.But the second graph seems to show that cycling 50% to 100% kept the most battery health when compared to 0% to 50%.
The calendar aging will have a 10x impact compared to the cyclic aging during the first ~ 5-8 years of the battery life.
For the 50-100% and 0-50%, we see a degradation in the worst case (50-0%) that equals about 1.25% cyclic wear in average until 25% is lost (which would take ~ 20years of average driving).
No one will drive like that (0% displayed is ~4.5% real SOC).
The 100-50% would loose about 25% after ~ 3000 FCE cycles so ~ about 0.45% each year.
Calendar aging will degrade the battery (in an average climat) about 5.5% in calendar aging the firat year if high SOC is used (above 55% mainly), se the chart (there is a similar for model 3 cells).
After 4 years we have lost 11% in calendar aging and after 16 years 22%
If we instead ise low SOC, we cut the calendar aging in haft, getting 2.75% first year and 5.5% after four years, and 11% after 16 years.
The first eight years will ”cost” ~8% calendar aging if low SOC is used, plus another 1.25% for cyclic aging each year= 18% total degradation.
If high SOC is used we double the calendar aging to ~16%, and the cyclic aging will be ~ 3.6% so in total ~20%.
IRL, the cycles will not end up with 50-0% in the car, and this research was performed with 1C load, which is equal to 75-80kW in the 3/Y.
We can see from other research (using nore representative power that low SOC is rather good. Part of this researchs result was due to the high current and charge discharge to the end point.
Again, the magnitude most be noticed and considered.The 3rd graph shows that cycling 5% to 15% did much worse than cycling 85% to 95%, which goes against the conclusion that lowest SOC is best above all.
5-15% equals 0-10% displayed SOC.
Still, being the worst case scenario the cells lost ~17-18% after 3000 FCE. This equals 3000 x 400 km driving range, so 1.200.000
The 1.2 million km is sufficient for ~60 years of average driving. So 17-18% /60 years = 0.29% in average for one year.
Compared to the 2.75% or 5.5% calendar aging the first year, 0.29% calendar aging each year is very low.
I guess you understand that cyclic aging is only a fraction of the total and that you should not look at cyclic aging mainly whenMaybe I am interpreting the graphs wrong, but according to graphs 2 and 3 it looks like cycling at the high range is better than a low range, but that goes against the first graph and the conclusion that you want to keep the SOC low to prevent calender aging.
The middle graph with cyclic aging at 100-50% and 50-0% use the extremes, and are not really representative, as the cyclic charge and discharge current are much higher than for real driving/charging.For reference, I typically use 30% during my commute. I’m trying to figure out if I should:
Cycle 25% to 55% (keeps battery below that 55% “cliff” in graph one)
Cycle 35% to 65% (keeps median SOC around 50%, which seems to do best in graph 3, but goes over the 55% “cliff” that also seems to cause a penalty in graph 3 in the 55-65 result vs the 25-35 result).
Regardless, I will definitely start using the departure scheduling.
Each 0.1V is about 10% SOC.
4.2V = 100%
2.5V = 0% true SOC.
3.2V = close to 0% displayed.
You can see that small cycles are better and that lower SOC also is better for the cyclic wear
You can see that we have the lowest degradation per cycle between 35-55%.
And that 25-35% is comparable with 55-65,65-75,75-85 and 85-95%.
So, even if any of this curves actually are showing degradation small enough to be disregarded, the best option for calendar aging, to charge to 55% any time thats sufficient will also cause very little cyclic aging
You should only consider calendar aging for normal average driving, as cyclic wear is negligible. And if you still wish to consider it, the best SOC range matches the max 55% charging level.
This is how to think:
- Do not charge more than you need until the next charge.
- Charge often (reduces the need above and reduces cycle size)
-charge late (reduces calendar aging, specially the times you need to charge higher than 55%.