Many online stores as well as local hardware stores have the required equipment to charge a battery with a solar panel. A small system is both efficient and portable. It can be installed in your yard, near a tent, on a boat or in any location that has direct sunlight.
Four pieces of equipment are required for this solar power system to work:
Select a solar panel with the highest possible power rating while still being easy to carry and handle. Solid panels are more rugged and produce more power than the flexible ones, but are not as portable.
Most panels are rated at 12 volts and are fairly inexpensive. For better performance, a 16 volt panel will produce more current and will charge the battery faster.
For smaller systems, a charge controller is not necessary, but the relatively inexpensive cost more than justifies the added performance and protection. These units will automatically disconnect the battery from the solar panel once the battery is fully charged. A unit with a maximum power point tracking (MPPT) circuit will also maximize the energy from solar panel.
Make sure that the controller can handle more than the peak amount of current from the solar panel. If more than one panel is used, make sure that it can handle the total amount of current from all of the solar cells put together.
The larger the battery, the more energy it can store. Look for a 12 V deep cycle battery that can withstand the numerous charge and recharge cycles. These batteries were designed to be fully discharge and then replenished without any damage to the electrolytes or internal plates. Car batteries are not designed to be repetitively drained and will soon fail to hold any charge if used in this manner.
The DC voltage of the battery is 12 V but most household appliances run at 120 V AC. An inexpensive inverter, similar to ones that plug into a car's cigarette lighter, can be used to make the stored energy in the battery usable to your household devices. The current rating of the device should be enough to accommodate your load. Look for one with the amount of sockets you will need.
Depending on the size of the battery, it will usually take a minimum of 5-8 hours to charge a dead battery from a solar panel that produces 1 Amp of current. In order to most effectively charge a battery with a solar panel, you need to maximize the amount of current by keeping the panel pointed directly at the sun. Try different locations in your yard or repositioning the panel ever few hours to maximize the amount of sunlight. If you really get into solar power, there is even a device called a solar tracker that will automatically turn your solar panels to the sun for maximum effectiveness!