The Case

• To hold the parts of your DIY solar battery charger you'll need to build a sturdy case. Materials used in the case aren't important, but in keeping with the green theme, you can use recycled wood, an old TV or CRT monitor case, or flooring scraps made from bamboo which happens to be both quick growing and a renewable resource. You'll need plenty of holes in your case for airflow and a frame to hold the battery and the DC charger controller.
  
  

Internals

• The components which actually make up the charger are easy to get and inexpensive to buy, available at most electronics stores. You'll need a solar panel--5-watt 12-volt photovoltaic should do, a solar DC charge controller for the panel, a 12-volt 12AH rechargeable battery, 5 feet of 18 gauge wire, a 1/4-inch mono jack, a cigarette lighter Y adapter and a DC to AC inverter (optional).
  
  You have to connect the solar panel and battery to the charge controller. Start with removing the lighter plug from the Y adapter, and then solder it to the mono plug. Insert the mono plug into the output outlet on the DC controller. Then connect the four power leads from the solar panel and the battery to the controller input terminals using the wire, checking that positive and negative leads are connected correctly.
  
  Run the panel outside the box along with the cigarette lighter socket.
  
  

Externals

• Once you've completed the wiring inside the box you're left with a solar panel and a cigarette lighter socket. You'll need to create an adjustable mount for your solar panel for efficient positioning toward the sun. An adjustable frame can be made of a small art easel using an adjustable rod to change the frame's angle. Point the panel at the sun and wait while the 15-volt battery charges up. Charge times will vary according to the amount of sun the panel receives. You can increase the power by adding more solar panels and batteries.
  
  When the battery is charged, you can connect devices directly into the cigarette lighter socket for charging, or connect a DC to AC inverter into the socket for directly plugging items into the charged battery.