The team concluded that the things guitarists dislike most about batteries are their brief lifespans, the hassle and cost of changing them, and the need to carry spares. Their solution was to make the Fluence battery rechargeable via a standard mini-USB plug. The battery runs for 250 hours on a single two-and-a-half hour charge. Unplugging the instrument cable turns Fluence off, conserving juice. (The “off” feature means you may have to replace your existing output jack with a stereo jack.) With a 250-hour charge, you could forget to unplug your guitar, go away for a week, and still have three continuous days of non-stop playing before recharging.