Haha I see I ruffled a few feathers. Yes the mobile charger is great if that's your only option but if you can get away with a 14-50 I think it is the best compromise. Cheap(er) and a little bit more wiggle room if you go over 15 miles a dayAnd then it'll also depend what you do in the following days - you can "catch up" easily if most days are a light commute.
You have ~300 miles to play with.