It's very important to get a sample bill from someone in your same billing area with your same electrical provider. Others are just data points for you. Here is my Duke Energy costs from Saint Petersburg, FL. If you also have Duke Energy in Jax, it's likely close but may not be the same.
CUSTOMER CHARGE ENERGY CHARGE - $11.40 per month then..
ENERGY CHARGE
FIRST 1000 KWH @ 8.144c
ABOVE 1000 KWH @ 9.859c
FUEL CHARGE
FIRST 1000 KWH @ 2.811c
ABOVE 1000 KWH @ 3.811c
ASSET SECURITIZATION CHARGE
PER KWH @ 0.251c
Below 1000KWH, my price is 11.206c and then it's 13.921c after that.
If you are looking for generalities for your HOA, a Model S is 100KWH so it's $11.206 to completely fill up a Model S from dead using the first 1000KWH number (ignoring charging loss) and $13.92 after. I would probably give them a general cost around 8 bucks for a 20-80% "fill-up".
I didn't know whether or not to post this....but If they want worst case number and they have a wall charger installed, that's 48A x 240V x 24 hours which is 276 KWH per day. Multiple that by 31 days and you get ~8500 KWHr consumed. 8500KWhr for me in Saint Petersburg is $11.206 + 7500*.13921 = ~$1000. Note this will NEVER happen but it's the absolute worse case if people are lining up day and night and immediately go from one car to the next, which won't happen at night. On the flip side, it does not include charging inefficiencies. They could always turn down the max amp from 48A to limit their exposure until they get a feel for it (move it to 24A and you'll have a $500 exposure, etc).
Two more things.
First, I heard the gen 3 wall chargers with wifi will be getting some sort of billing capability in the future. They've been out for over a year already so I wouldn't hold my breath but that would be perfect for places like your condo. Then they could charge back.
Second, there's a good chance Tesla will give wall chargers to them. Please see
Charging Partners | Tesla....