I've though about solar panels, but it's not realistic because it just trickle charges the battery. Maybe if you had two batteries and left one charging all day it would work.
I was thinking more along the lines of kenetic energy...
The weza freeplay... that lever in the back is actually a foot pump the recharges the battery....
and it has a solar port too, if you wanna plug one of those in for added support. Think about it, you could just stand there pumping to the beat if you just need that little bit more juice to end the show.
"A Must Have Essential energy power source for:
Cabins, Travel Trailers, Year-Round Campsites, Wilderness Guide Services and Expeditions and living Off-The-Grid.
The Weza FreeCharge is a portable power supply putting out 12V DC through a standard "cigarette lighter" style plug. It puts out enough power to jump-start a car or boat, but can also recharge most portable devices.
But what's so cool about it is the way that you charge it, You step on it. More precisely, you use the "step treadle," meaning that you step up and down on it for a short while to bring the battery back up to full. If that doesn't sound fun, the Weza step-powered generator is designed to be charged with solar panels and small wind turbines (Freeplay recommends a 30 watt rating). You can even recharge it from a wall outlet, but that's cheating.
The Preparedness Center is proud to work with Freeplay, a company where quality and long-life durability are built-in values. Freeplay's new Weza has a feel to it like a warm, dependable wood stove. This solid, foot-powered energy source really pumps out the juice at up to a 30-watt rate to charge its own internal battery for direct 12-volt power. To charge it, you simply step down on the pedal and the generator spins.
Charging to full power takes modest dedication. When combined with one of our power stations you can use it to run and recharge emergency lights, small power tools, or power a computer system or watch a mid-size TV for hours while losing weight. Power outputs include negative and positive posts with an excellent set of beefy jumper cables and a cigarette lighter output. A line of LED's gives you your charge rate while pedaling and battery level with the touch of a button. AC adapter included for couch potato charging.
Freeplay's first non-dedicated charger is a very attractive alternative for well-off-the-grid use, and would be a good companion to a small photovoltaic system such as those found in remote cabins, travel trailers, year-round campsites, wilderness guide services and expeditions.
Weight: 20.5 lbs.
Size: 8.5" W x 11.1" H x 17.25" D.
66" jumper cables.
Two-Year Warranty."
"Features & Benefits
No disposable batteries required
Self-sufficient power - AC/DC, step treadle
Powers products via 12 V DC cigarette lighter adapter
LED display bar for battery level indication
Can jump start automobile motors, boats, ATV's
Recharge from AC or DC power sources
Includes: jumper cables, AC/DC charger, service tool kit & waterproof carrying bag
Weight: 17.75 lbs. with battery
Specifications
Human powered input 25W - 40W with effort indication
7Ah sealed lead acid battery
Heavy duty jumper cables
12V cigarette lighter adapter output socket
110V - 240V DC charge input
12V - 18V DC receive charge capability
Battery level indicator"