You don't believe it makes it more complicated ? Comparing price per kWh (simple) versus price per kWh plus price per minute (more factors). One is clearly more complicated than the other. You are right we do not have to add up the billing for the machine, but it would be a fool that didn't check it.
Fair ? So a vehicle that can charge faster than mine usually a more expensive one, will be able to charge quicker and therefore more cheaply than me for the same goods.
Fair ? We all know charging rates vary depending on many circumstances, SOC, temperature of battery, temperature of weather, so the price would vary depending on weather as it would take longer to charge the same amount in winter compared to summer. - Perhaps we should all get a winter fuel allowance.
I fear you are trying to solve a problem by creating another. Overstaying is easily solved by simply charging for overstaying, not by fiddling with the cost of the commodity. The best solutions are often the simplest.
We'll have to agree on having differing opinions on this one.
I do think it is very fair to also bill by time.
From a business perspective, companies installing/operating the chargers, need to make a profit otherwise they will not install them - and we need them to install more. Their costs are fixed and variable, covering their fixed costs is proportional to the amount of time the unit is available.
An overstay £charge sorts out people leaving their cars connected once they are fully charged, but it doesn't discourage people from charging at a really slow rate and tying up the unit when at the higher SOC.
In theory by also billing by the minute, the costs for normal folk like ourselves using these chargers to only usually charge to around 80%ish, would be lower than they are currently, as the companies can make the same overall profit with lower £per kWh&minute.
IMHO I do not think the mentioned super market analogy is appropriate. Unless you add in a restriction that only a few people are allowed in the shop at any one time (the same as only 1 car can use a charger at a time), if this were the case supermarkets would change the way that they charge.
I know this actually makes things more complicated!!!!! which no one wants, but I can imagine it going one stage further and the following happening at some point:-
Charger units have more than one CCS cable/plug so multiple cars can charge concurrently should there be enough capacity.
It billing at X pence per kWh PLUS the customer chooses the charging rate
Xpence per minute up to 25kWh
Xpence per minute up to 50kWh
Xpence per minute up to 75kWh....etc
From a setup costs perspective, it wouldn't cost much to add additional CCS cables to the unit; DC chargers have multiple converters fitted within them to get the kW allowable output, the more of these the higher the unit cost, so these could be routed individually to each car and therefore get the additional investment back (thus the rate price banding based on the number of/size of the converters)
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