Arguably it should be far easier to get those economic incentives aligned as chargers are far simpler mechanically (they are just plug sockets with weird over-engineered male adapters) and most of what breaks on them is either vandalism or a small subset of existing problems of gas pumps: credit card reader malfunctions, display/screen problems, internet connectivity issues for account management/credit card transactions. (All the human UX points of contact.)
> Once EVs stop competing on range so much, it'll make sense to just designate the last 10% of battery as "reserve" and not count it in the battery level indicator.
Most already do (even while still competing for range) because it's a battery maintenance requirement. Li-Ion cells generally don't like being 100% full, especially not for long periods of time, and sometimes have a preferred "directionality" (ie, a cell should only be charging until it hits 100% and then you can draw from it and vice versa once you start drawing from the cell you should keep doing so until it hits 0%) so battery controllers already have to do a bunch of math to keep a "reserve" so that they don't violate "directionality" (you always want cells in the "charging" direction available even while driving for regenerative braking storage, for instance) and don't generally hit 100% charge for long rest periods, but instead 95% or so.
> it'll make sense to just designate the last 10% of battery as "reserve" and not count it in the battery level indicator.
Very questionable? Why would you do that?
We don't do that for gas cars either.
I once, embarrassingly, found myself on the highway with an empty tank of gas and 20 miles to the next gas station. I watched the estimated miles remaining indicator tick down mile after mile, ticking precisely my passage. At 3 miles estimated remaining, I pulled over because there was a very wide safe shoulder, and I didn't want to putter out in a less-safe spot.
I don't want to try the experiment of letting it tick down to zero and seeing if I still have 10 miles or so left.
I think the use cases for field-swapping a (part of the) battery pack are the same as for carrying extra fuel canisters with you, which I can only speculate about, because I've never been in such situation with an ICE car.
That said, it's probably a UX problem. Once EVs stop competing on range so much, it'll make sense to just designate the last 10% of battery as "reserve" and not count it in the battery level indicator.