The idea is to avoid running an
individual cable from each car space back to a central control/metering
point in a basement. Instead the control and metering would be at the socket, with the
sockets wired in parallel. Also the wiring would only need to carry
about one eighth* the load the sockets could theoretically supply. There
would just need to be a dumb circuit breaker for each string of sockets,
in case the automation failed and tried to power too much at once.
Smart high power chargers already have the capacity to be remotely
controlled and used for metering, but cost thousands of dollars, and require expensive high capacity circuits to be run to the building. The power also costs money. A low cost alternative would be an
ordinary domestic outlet with a smart controller built in. The
householder would simply plug their car in to charge, or if security is
needed, use an app to start. The smart system would charge only about
one in eight cars at a time*, monitoring which cars had charged, & which
would accept more.
A workable setup might use a 20 amp cable, with 16 sockets, but only two sockets ever being active at any time. A system would ration the power available, between the cars. Each smart power point would report when power is no longer being drawn from them, indicating the car no longer needs charging, and can be provided to another. The householder could have the option of only using off peak low cost power, or on-site free surplus solar power.
* Back of the envelope calculation:
The average Australian car travels about 33 km a day.
An electric car, such as the Tesla Model S, uses 19 kWh/100 km.
So that is 6.27 kWh per day per car needed.
From an Australian domestic outlet you get 2.4 kW.
So it will take 2.6 hours to charge for an average day driving. Let us round it up to 3 hours. So in 24 hours you could charge 8 vehicles from one outlet.
So it will take 2.6 hours to charge for an average day driving. Let us round it up to 3 hours. So in 24 hours you could charge 8 vehicles from one outlet.
ps (added 6 July 2023): Laws restrict what the body corporate which runs an apartment block, and companies supplying power, can do. The body corporate typically can't charge householders for electricity generated on its own roof, nor can they contract for a bulk supply, & charge for that. Also the companies who can charge, and how much they can charge, is heavily regulated, creating monopolies which can make super-profits. An alternative approach might be for the body corporate to levy householders a fixed amount in advance for car charging. This would be based on the number of car charging spots the household has. If the charging is only low rate, it may not be worth metering individual apartment use: everyone would pay the same amount per car. If it is worth metering, there could be a refund, for power not used.