I agree a simple meter like the one Jimmy linked to may well be sufficient, especially while EVs are not common. That is what I have on a line from a neighbour’s unit that is conveniently next to our shared parking area. That works while my neighbour’s electricity tariff is flat rate. If there had been a way to have the line run back to my unit’s meter box I would have preferred that. I am on a time of use tariff (voluntarily) so I can run mostly discretionary loads such as the electric boost for solar hot water or the dishwasher on off-peak most of the time and save some money while having the option if necessary to run them any time. It would be nice to charge the cars that way too; usually on cheaper off peak but able to charge at any time if I need to. It is not really a big deal since an electric car is cheap to run anyway but the time of use tariff would save me enough money for an extra meal out occasionally.