The solar panels are available at Northern Tool. These panels are not very efficient but are great for the hobbyist. I have one and I use it to charge reused UPS batteries. It takes forever to charge them. The price has come down some and I’ve seen them for $75.
http://www.northerntool.com/shop/tools/category_alternative-renewable-energy+solar-panels-accessories+amorphous-solar-panels
Here are a couple more web sites that sell better panels.
http://www.solar-electric.com/1to39wasopa.html While this site is not the cheapest, they provide great service and a excellent solar forum.
http://www.ecodirect.com/40-Watt-Solar-Panels-s/26.htm This site has some cheaper panels. I purchased two of the 80 W Sharp panels to provide lights… power to my shed. Shop the prices and you can find what you are looking for.
Keep in mind that you may want to combine more than one panel but that is more real estate. One higher wattage panel may be a better option because it is easier to mount and usually provides more amperage. I would also recommend making an adjustable mount to adjust for the angle of the sun. This changes depending on the season.
Another thought, most of us have weather stations, place the panels angle to match your latitude. Mine is 34 degree’s. This will help make the panel more efficient.
Have Fun
Marshall