This is precisely the problem that we're facing in our condo complex. For about the same money spent by the 10 owners above, there could have been 50-80 x 110v outlets installed, so that the inevitable crunch for access to any outlet for EV charging would be kicked down the line for about 10 years.
I can bet that each install involved a 208v/50 amp or greater breaker at the main panel, given the cost.
Since each of the 10 installs was for 10 individual owners, each install was a one-off and so there's no economies of scale. One install with 5-10 subpanels, with each subpanel supporting ~8-16 x 110v installed outlets would probably cost about the same.
Strata/HOA could mandate that when an EV owner wants to install a charging station, they must install a subpanel and run their outlet from the subpanel and then be prepared to share the subpanel (on a cost recovery basis) upon request from other EV owners.
The vast majority of the cost of the installation of the 10 240 volt circuits was the cost of the conduit and its installation labour. When I was last there they had installed some of the circuits, but there were no EVSE installed, and I have no idea if they installed 6-20, 14-30 or 14-50 outlets or EVSE, there was just conduit to some of the parking stalls and boxes with blank covers on them. The second biggest cost was the wire and the labour for pulling it through the conduit. The third biggest (and a distant third) was the Wall Connector or the Mobile Connector. Installing 50-80 120 volt circuits in this parking garage would have required vastly more conduit and be much more expensive, and there is no demand for that many circuits right now. This building was finished about 4 years ago. I don't know if there were EVSE with load management capabilities back then, but if someone at the building had thought through this, I think they could have limited the circuits to 20 amp 208 volt and could have stretched it out to maybe 20 or 25 circuits, but they would still eventually overload the electrical system's capabilities. I do agree with DuncanM that using sub panels in a large multi-level parking garage could definitely reduce the costs (but it wouldn't be "the same"). But please consider that using EVSE with load management capabilities, such as the Tesla Wall Connector, can further reduce the costs for large deployments as they can go as low as 6 amps, which at 208 volts is only 1,248 watts (less than 120 volt 12 amp charging) when necessary, but will usually charge much faster than 6 amps, with the benefit of being more efficient (perhaps even more than "marginally efficient" as I said above, it depends on the definition of "marginal)) and able to bill for the energy used with no additional hardware, and the wiring required is exactly the same as for a 120 volt circuit, except no GFCI outlets or breakers to pay for and fool with.
If I was planning such a system today, I would try and figure out a way to maximize the number of EVs that could be accommodated without having to increase the power coming into the building, whilst installing wiring, conduit, sub panels, EVSE, etc., that would not be wasted at the time, say 10, 20, whatever, years from now that the building's power capability eventually had to be increased.
It depends on what those 10 installs were. If they were 50A each, that is 500A of capacity which could support ~66 15A 120v outlets.
But there is no way that the cost to install 10) 14-50 outlets would be the same as 66) 15A 120v outlets. There is going to be a whole lot more wire and labor involved, as well as requiring a larger panel.
The way I see it, the only economical way to have a large number of effective charging spots is to use load-balanced EVSEs.
Going with so many 120v outlets would really require a way for people to pay for what they use. Something like Orange outlets, but they cost $500/each and then they charge $20/month plus 5% for the billing services. (~$16k/year + 5% for those 66 outlets.) And they still have to provide their own EVSE, which is way less convenient than having an EVSE with the cable right on the wall. Which makes it very not cost effective, at that point you are better off going with the Tesla Wall Connector for $475/$595 where Tesla only charges $0.01/kWh for the billing services. And yes, that same 500A of capacity can support 66 load-balanced Wall Connectors.
I do not know the amp capacity of the ~10 circuits, but it would not require 500 amps x 208 volts or 104 kW of capacity just due to the diversity effect of the way loads are not all on at the same time.
The manager told me the existing installations are grandfathered, but if those installations do put a load of 50 to 100 kW on the building (the building has a 1500 kVa transformer), that amount of power could be used much more efficiently by installing a system that uses EVSE that manage the load, although the exiting owners who were early adopters might have a thing or two to say about giving up what they have. Might require quite a bit of work by someone someday to straighten this out.
OK, using yourself as an example, if you're charging was limited to 110v/10a x 10hrs/nightly, and starting from Monday at 100% SOC, where would your SOC be on Friday?
When I have talked to our strata council, anything that involves EV owners cooperating is a non-starter. Self owned metered reporting and/or a flat fee per EV charging outlet based upon average weekly driving is OK. Strata will not manage access to a shared on-site charging station.
Some buildings may be different than yours. For example, the building I mentioned will reserve various club rooms for residents. They may be willing to do that for a couple of EVSE that would be used when needed, and why would anyone who has the 120 volt charging that you say is adequate for most people want to go to the trouble of doing that except for when they need it? This particular building has a full time front desk, and valet(s) who could manage and enforce the communal EVSE.
This discussion will never end. Each building has its own unique situation which is how much reserve capacity, if the HOA board is willing to work with the EV owners, and so on, but right now no HOAs (or very few) are forward thinking enough to want to deal with this issue.
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