I've been able to continuously power an 80 watt device for approximately three hours without interruption and it could have gone much longer, as well as run an electric drill under load with no hesitation or slowing. This is one powerful machine!
Remember as you construct your device that Volts x Amps = Watts.
There are a couple things to note before proceeding.
1) This is my first Instructable, I hope I get it right.
2) I am not an electrician or a handyman. I'm just an average Joe who used resources available to me and figured out something cool. This Instructable involves wiring. If you are not comfortable doing it or if you don't know what you're doing, learn before doing and don't blame me if you zap yourself.
What you'll need:
1) Battery (I used a 12V 26AH battery that I ordered off the internet for about $65)
2) Inverter (I used a 410 continuous watt inverter that I bought at Wal-Mart for about $35)
3) Charge Controller (I bought one off the internet for about $18)
4) Solar Panels (I used the garden lights that I bought from Wal-Mart for $0.97 each)
5) Electrical wire
6) Soldering Iron and solder
7) Wire strippers
8) Something to bracket everything down
9) "Normal tools" (needlenosed pliers, screwdrivers, stapler, drill, etc.)
10) Dremel tool or sandpaper
Step 1: Prep the panels
Remove the top of the garden lights and expose the screws.
Unscrew the "lid" and set aside (don't throw it away). You should see some hardware (battery connectors, wires, LED, battery).
Remove all the unneeded hardware - this would the battery, the wires for the battery (make sure you don't pull out the panel wiring), battery connector and LED.