When I pull into a location with a level 3 or level 2 charging station on my long journey I am looking for an opportunity to take a break and get something to eat while my car charges.
Depending on the charger, the car will need to be plugged in somewhere between 15 minutes and a couple of hours.
I don’t want to hang around while this happens, I want to do something else.
In order to make this convenient for me, my car will likely be sitting there more than is necessary.
However if it is, it may block someone else who wants to charge.
Either it is plugged in and not charging, or an attendant disconnects the cable when I am done.
The most sensible solution in my opinion is to have more spaces than there is charging capacity.
Suppose 200kW of charging is available and there are 20 parking spots and 20 cables. Each cable has a maximum output of 50kW.
You pull into an available spot and plug in, but there are 4 cars ahead of you, all pulling 50kW.
When one of them is done, 50kW will flow to your car.
When your car is done, the charging stops and you receive an email or text telling you your car is done.
Of course if you leave your car connected long after t is done, you should be charged extra for that time.
At the absolute minimal manually operated level 2 charging station, a single cable could easily reach 6-8 parking spaces.
Here it may make sense to have an attendant move the cable from car to car, as he is notified that charging is complete.
I would expect to find this kind of scenario at a shopping mall or other urban setting.
In this scenario there are several cars that are all going to be parked for several hours, and each needs only a fraction of that time ( an hour or so ) of charging.
I think that it makes the most sense to have an abundance of cables and all the cars plug in.
You enter in to a system how much time you expect to be there and how much charge you want.
The charge station budgets its power to all the cars that want it.
Because it knows how long each car intends to stay, it can maximize the energy to everyone. If the system is billing by how much energy you get, then it is also maximizing its revenue.