The math is actually pretty straightforward. As mentioned before, you can expect to get full L2 charging rate at pretty much any starting state of charge as L2 charging is pretty linear regardless of the pack size.
This formula will get you the time in minutes to add y number of kWh to the pack:
time in minutes to charge = (y kWh x 60 mins/hr) ÷ 6.6 kW
So, if y is 1 kWh, then expect charging to take about 9 minutes. Also, each kWh of energy adds about 4 miles of range (this varies a lot based on driving conditions, but it's a decent ballpark number).
For simplicity sake, I round up the charge time per kWh to 10 minutes. So, if you plan to eat lunch at a restaurant while charging for 30 minutes, you'll know you'll have added roughly 3 kWh to the pack (and added roughly 12 miles of range).
Vancouver, CA owner of a 2013 Ocean Blue SV + QC, purchased 01/2017 in WA
Zencar 12/20/24/30A L1/L2 portable EVSE
1-1/4" Curt #11396 hitch
After market, DIY LED DRLs
LeafSpy Pro + Konnwei KW902 ELM327 BT OBDII dongle
Loving my first BEV