Solar Laptop Charger
Tour a middle-class home in the U.S., and you're sure to come across an old computer collecting dust in a closet. Not so in developing countries, where families have little hope of using a PC to get a weather forecast or do research for school.
Getting laptops to these regions is just part of the solution. The United Nations estimates that 1.5 billion people around the world still live far from their country's electric grid, which means powering electronics is almost a bigger problem than getting them in the first place [source: Rosenthal]. Small-scale renewable energy, especially solar, can provide a viable solution. Many families in Africa have installed small solar power systems on their huts, enabling them to charge a cell phone and run a few lights.
It's also possible to harness the sun's energy to charge a laptop, and a few off-the-shelf products make it easy to do. A typical offering comes with a 16-watt solar panel and a battery integrated into a laptop bag. You can make the same thing if you're handy and have access to a few tools. You'll need to acquire the core components of the charger: the solar panel, 12-volt battery packs, a 12-volt car power outlet and an old suitcase or briefcase slightly larger than the laptop. Then you'll need to remove the padding from the case to make some extra room. Next, mount the solar panel, the solar charge controller and the car power adapter to the outside of the case. You'll need to drill into the case frame to accommodate attachment screws and to create holes for wiring. After that, disassemble each battery pack and reconfigure the 10 cells so that they form long flat packs that fit easily in the case. Attach leads to the packs a, link all of them together and attach them to the positive and negative terminals on the solar charge controller. You can find detailed instructions here.
When the device is done, set it in the sun and let the batteries charge for several hours. Then you'll be ready to charge your laptop and anything else that can be plugged into a car adapter.