the bmw i3 takes 40 minutes to charge to 80% at a rapid charge station 100% takes an hour and 15mins which isnt inconveniant on a long journey i would be wanting a break around then anyway.
4 hours on standard charge to 100% on your home charger. most people have an overnight cheap rate.
in my case as the longest journey i normally do is about 60 miles round trip i would only need to charge once a week.