djp
Model 3 Performance
In general I agree CAC is just an estimate and it can overshoot the true capacity of the pack, but it is the best number we have. The only time that CAC gets accurately measured is when the car is driven from a full charge down to close to zero. If you're only using the middle of the range the CAC slowly drifts upward and overstates the true capacity.
As far as I've seen the displayed range is a simple multiplier of CAC and SOC LIM. The pack reaches a higher SOC LIM when charging on 120V. I usually see a Standard charge SOC LIM of 83% on 240V and 84% on 120V, which accounts for the difference in displayed range.
Disagree on this one. The NREL study has a graph of degradation rates at various temperatures and SOCs. I agree with Martin that the biggest step is from 100% to 80%, but there are still meaningful benefits in maintaining a lower average SOC. For example, at 25C the graph shows it would take 11 years to lose 20% capacity at 80% SOC and 17.5 years at 60% SOC. I'll take the extra 6.5 years.
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The range numbers supplied by the car are apparently calculated from the same information used to calculate the CAC, as the two move in the same direction. We do know the relationship between the two is not just a simple multiplier. My guess there is that how you charge, and from what initial charge, has more of an effect on reported Ideal Range than on CAC.
As far as I've seen the displayed range is a simple multiplier of CAC and SOC LIM. The pack reaches a higher SOC LIM when charging on 120V. I usually see a Standard charge SOC LIM of 83% on 240V and 84% on 120V, which accounts for the difference in displayed range.
Not doing a full Standard Charge is not worth the effort unless you're not going to be using your Roadster for months (plural) and/or is being stored in very high ambient temperatures.
Disagree on this one. The NREL study has a graph of degradation rates at various temperatures and SOCs. I agree with Martin that the biggest step is from 100% to 80%, but there are still meaningful benefits in maintaining a lower average SOC. For example, at 25C the graph shows it would take 11 years to lose 20% capacity at 80% SOC and 17.5 years at 60% SOC. I'll take the extra 6.5 years.
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