dgpcolorado wrote: ↑
Wed Dec 02, 2020 1:35 pm
Your assumption of 20% as a lower limit to preserve the battery isn't reasonable. Occasionally going down to 5% or so is no big deal, as is charging to 100% just before setting out on a trip. Setting artificial limits on battery use to limit usable range is not reasonable for road trips. That's simply not how it works (nor should it). Keeping the battery in that 20% to 80% temperate zone for local driving is fine. So is using the whole battery on occasion when needed, so long as it isn't left at high or low charge.
I'm not aware of any Li-ion chemistry that is comfortable being depleted semi-routinely to 5%, although you can of course do so if you choose. But that implies what is to me an inadequate reserve: 5% of 178 is only 8.9 miles. Personally, I want a soft reserve of 20%, and a hard reserve of the greater of 15% or 30 miles. That latter number has long been used by CR as a reserve when calculating a car's range, but is often wholly inadequate for BEVs given the current spacing of stations.
Perhaps our different attitude to what we're willing to do to a battery depends on a different attitude towards a car's expected usable lifetime. For me, that's >= 15 years.
As to what range is adequate on trips, you're retired and thus can afford to spend more time enroute. Even if that weren't the case, I suspect you possess far more patience than I do.
And while your S60's range is far too limited for me, it does at least charge considerably faster than the Bolt I drove across the Sierra and back, including having to spend over an hour gnashing my teeth in a Walmart parking lot while it charged from 77 to 100%. Given better charging site locations, closer spacing and more reliability of charging I wouldn't have had to do that, but lacking all of the above on that trip, especially the latter, it proved to be essential that I did so.
All that being said, I don't think 300 EPA miles will be enough for the general public, because in their mind those miles come with a whole host of understood conditions common to ICEs, most of which don't now, and in some cases may never apply to BEVs. For example, to provide a practical range for the life of a BEV roughly comparable to a "300 mile" (HWY+ reserve) ICE, the BEV would need something around 700 miles of range. This is based on the following, and only covers 8 rather than 15 years, as that's the longest capacity warranty currently offered): 700 x .7 (degradation) = 490 x .6 = 294 miles. Note I'm not including any allowance for HVAC use or adverse conditions, all of which are included in the ICE's "300 mile + reserve" range.
To me, the above calc indicates that the most important factors in an improved battery are reducing degradation over time, and also allowing a wider SoC range to be used without hastening degradation. Failing that, battery leasing.