Keep in mind the Gen II Volt by EPA numbers is between 5% (hwy) to 12% (city) more efficient than the Gen I Volt.OK, let's assume a battery reserve of 4.4.kilowatt-hours. I've been keeping a spreadsheet of trips in my 2015 Volt in mostly city driving, and the average miles per kilowatt-hour is 3.39. If that number is taken as a benchmark, it means that the 2011-12 Volts should have an average range of about 39.3 miles, the 2013-14 Volts should have a range of about 41.0 miles, the 2015 Volts should have a range of about 43.1 miles, and the 2016-17 Volts should have a range of about 47.5 miles. However, I should note that my average miles/kWh has a 10% standard deviation, so there's a big variation associated with these numbers.
Also on the Gen I Volt EV range usable battery was about: The unused battery on the Gen I Volt was 6KWh.
2011 - 2012 - 10KWh
2013 - 2014 - 10.5KWh
2015 - 11.1KWh