Battery backed DC fast chargers only work as planned if there's low utilization of the charger, so it works when there are only a few vehicles that use it unless the battery is HUGE, but when plug in EV use increases even more in the next few years the complex will have a lot of frustrated users that will take several hours to charge after the battery power is depleted after the first user does a 10 to 80% charge.
It may be better for the property owners to put in a system of battery backed, load balanced, lower powered DC or L2 chargers with multiple outlets to limit peak power usage on their power limited distribution system so charge times are slower, but more consistent.
Plus efficient use of shared chargers depend on users being responsible and moving their vehicle when they're done and creating a practical queuing system, which in real life isn't something that people do well.
