I was recently sent a sample of the new Sanyo Pedal Juice, a rechargeable lithium-ion battery for powering effects pedals. I've had a few chances to use it on gigs, and I'm ready to tell you about it.
The setup I used on these gigs was pretty basic: my Strat through a Boss TU-2 tuner and Blues Driver to my amp. I almost never use 9V batteries in my pedals, as I fear that I'll forget to change one out and get caught with a dead pedal mid-set. I always prefer to use AC power, so my usual plan with this setup was to use the tuner's AC adapter and its built-in AC out jack to daisy-chain power to my other pedals. The Pedal Juice basically fills that latter role of the AC out jack without the need to find a wall outlet. The setup for this little rig is painless and quick. I just take my two pedals and Pedal Juice out of my backpack, plug in my guitar cable and push the power button. The Pedal Juice takes some extra space, but there's no more issue of tapping the wall power.
I had one problem with it on my first night. I was using the same AC daisy chain cable that I'd used with my tuner, and I'd occasionally get a crack and no more power. I remembered from the manual that letting two of the power connectors touch while the unit is on is like crossing the streams. Oops. I swapped out the messy daisy chain for the two provided single AC cables, and all was well. So using a daisy chain with eight connectors for just a couple pedals might be unworkable, as the free connectors are liable to touch, torching your tone.
Sanyo claims that the Pedal Juice provides up to 50 hours of play time powering a single pedal. That's much longer than batteries would last, and it's much easier to recharge the unit than swap out batteries, but my essential fear of forgetting to maintain the power source hasn't been solved, only delayed. One feature helps though: the LED power light turns from green to orange to red as the available juice diminishes. It's at orange now, so I better take note when it turns red.
It's not a perfect solution to the pedal power problem, but the Pedal Juice does make things a little more convenient. I'll keep using it.