My commute is 23 miles, which usually leaves me with around 11 bars (9-10 in the winter, usually 12 in the summer). I fully charge every night when I'm driving the i-MiEV the next day.
Since you have level 2 charging at work, giving the car 2 hours of charging per day ought to keep it from fully charging (that top bar could take an hour or more to complete due to tapering and balancing), but still get it pretty close. What you can do is program the ON timer for 2 hours and the ON->OFF timer for 4 hours when you arrive at work and plug in. This will delay charging for two hours to let the battery cool down a bit, then charge for 2 hours, and then stop. Once the timers are set, subsequent days will remember the times, though you will have to cycle through the timers and hit the right arrow button once for each timer to enable them, and then press send. The button sequence to enable the timers after setting them the day before are:
Hold power --> Right arrow once --> Mode --> Right arrow once --> Send
What's nice with how the timers work, is that if you get to work late or early, the same button sequence will have the start and stop charge times end up being at nearly the same times of the day as normal. Even though they appear as simple timers, the car uses the values and adds it to the current time of day to set trigger times. So, a 2 hour delay set at 8 AM will start charging at 10 AM. If you get to work at 7 AM one morning and go to enable the timers, it'll say 3 hours instead, so that charging still starts at 10 AM.
"Bear" - 2012 Diamond White Pearl ES with QC - 2/21/2013
"Koorz" - 2012 Cool Silver Metallic ES with QC - 1/5/2015
"Photon" - 2017 Bolt EV LT in Orange with QC - 7/31/2017
Solar-powered since 10/10/2013