Join Date: Sep 2005
Bikes: Windsor Fens, Giant Seek 0 (2014, Alfine 8 + discs)
LiIon batteries have gotten really cheap, and with the runtime you can get with them, you probably wouldn't have to worry that much about running out of power.
I bought a MS P7 system, and put the charger in the garage with the cord hanging right there. It has a 3 hour run time, and I run typically 40 minutes per direction, most of the year the lights are only on in one direction, so I plug in every 2 days. I could go 3 or maybe 4 but it's better for the batteries to not run them down, and it takes 10 seconds to plug the batteries in to the charger, and this way I've always got an hour in the tank so that even if I have a flat or something I'm OK.
Work: the 8 hours that separates bike rides.