<i>At some point later I got around to playing with DC fast charging ... That market still has a long way to go as far as sorting out its business model, as billing based on time vs energy is completely unfair ... An excuse that's offered less and less often is that pricing by kilowatt-hours delivered is prohibited in some states by utility regulatory rules.</i><p>I didn't know they were billing for DC charging in the US based on Time instead of kwh. Thats odd. In Europe its just kwh.
> In Europe its just kwh.<p>In the EU, yes. When you go to those dark corners of Europe that never achieved the membership, all bets are off.<p>In Montenegro and Serbia they charge per minute because the only entity allowed to sell kwh's is the national electricity company (in Serbia it's owned by Russia, so it is heavily legally protected).
In Italy there are enough chargers that charge for both kWh and time connected. kWh for what you use and connected to discourage being connected all the time.
No need to go further than dead center EU to see chargers where the cost has a time component, and an energy component, and even a (small) one time fee. Sometimes the charger is inside a paid parking, there that comes on top. These aren't shady operators either either, just the way they saw fit to prevent abuse and make more money.<p>Some have reasonable limits to prevent abuse [0], others just charge the customer as much as they can get away with.<p>[0] <a href="https://www.tanke.io/oeffentliche-ladestationen/" rel="nofollow">https://www.tanke.io/oeffentliche-ladestationen/</a>
It's almost all by the kWh here, but perusing PlugShare I've seen a few level 2 chargers here and there that charge by the minute. Usually that's a sign of a charger that was set up a while ago and is owned by someone who hasn't checked on it since.
I've never paid by the minute. Tesla Superchargers often deliver less energy per minute when they're busy (sometimes much less!) and it would be frustrating if they charged per-minute.<p>Other systems I've seen (Chargepoint) also seem to be energy-based.<p>The Supercharger network is well done. It's a shame that they took this long to open up to other car models because they really do get a lot of things right.
Arguably it should be both. Sitting and occupying a DC fast charging booth, especially once you're not charging at the full rate, represents an opportunity cost since someone else could be using it.
I used a Tesla charger (as a non-Tesla driver) recently. I think their pricing model is pretty good: pay per kWh (varies between peak and off-peak), and if the station is busy they can impose a "congestion charge" for anyone occupying a charger and not charging, or charging above 80% when it's not necessary for their journey (presumably only works for Teslas where the satnav knows about your journey and charge locations).
> especially once you're not charging at the full rate<p>I don't think you want that as no car will be able to charge at 250kW for very long for example.<p>And I believe we're starting to see even higher peak charging rates. As always, there's no simple answers
I think fast chargers in rush hour times will also bill for time to discourage long/slow charges on them. Naturally that'll vary on whoever sets the costs, but it does exist in EU as well.
I’ve charged in 30 states, it’s kwh every single time.
In Europe, sometimes it's just kWh, other times it's kWh and time. After charging is done, it's just time.