How to Transfer Solar Energy From a Solar Panel

A solar panel will generate direct current (DC) electricity when placed in the sun.

Roof-mounted solar panelsRoof-mounted solar panels
This electricity can be used to power some DC appliances directly, but more often the electricity is run through wires to a charge controller and then to a battery where it is stored as 12-volt DC power. To use this electricity to power regular household appliances, an inverter is used to convert the 12-volt DC electricity from the battery to 110-volt alternating current (AC).

Inspect the back of the solar panel and note the maximum power voltage and the maximum power current produced by the panel. This information will also be in the installation manual that came with the panel when you bought it. Check that the panel produces a voltage less than 20 volts. This means that the panel can be used for a 12-volt system.

Decide what kind of battery you want to use. There are batteries that are specifically designed for solar photovoltaic (PV) systems. They are called deep-cycle batteries. A 12-volt car battery will also work, but it will not last as long as a deep-cycle battery. Many deep-cycle batteries are 6-volt. If you are going to use two 6-volt batteries, connect them in series by connecting the positive terminal of one battery to the negative terminal of the other battery with a battery interconnect cable.

Decide where you are going to install the solar panel and the battery. The solar panel should obviously be in a place that gets plenty of sunshine -- most often on the roof of a building. The battery, on the other hand, should be inside the building in a well-ventilated space. But the solar panel and the battery should not be too far apart. Keep the connecting wires as short as possible. Measure and write down the distance in feet between the solar panel and the battery.

Buy a charge controller for the 12-volt battery. A charge controller will ensure that the battery is not overcharged by the solar panel, which could seriously damage the battery. Go to a store that sells this kind of equipment or check out one of the many websites on the Internet. Select a charge controller for a 12-volt system that is designed for the maximum current generated by the solar panel.

Determine the AWG gauge of the wires that will connect the solar panel to the charge controller and the battery. Read carefully the instruction manual for the charge controller. It will usually tell you what gauge copper wire you will need to buy. Double the distance you measured between the solar panel and the battery and buy this length of wire.

Cut the copper wire into two equal lengths with wire cutters. Take one of the wires and make a mark in red at each end of the wire on the insulation. This will be the positive wire. The other wire will be the negative wire. Cover the solar panel so it is not producing electricity. Connect each wire to one of the terminals on the back of the solar panel. Connect the positive wire to the positive terminal and the negative wire to the negative terminal.

Install the charge controller on a wall close to the battery. Run the two wires from the solar panel down to the charge controller, attaching the wires to the wall at various points if necessary. Cut the wires so that there is just enough wire to connect to the charge controller. Set aside the remaining length of the two wires.

Open up the charge controller and look at the instruction manual. The controller will have three sets of two terminals. One pair will be labeled "solar panel" or "PV," one pair will be labeled "battery," and one pair will be labeled "load." Each pair of terminals will have a positive and a negative terminal. Connect the positive wire from the solar panel to the positive terminal of the pair labeled "PV," and the other wire from the panel to the negative terminal.

Take the length of positive wire that remains and connect one end to the positive terminal of the pair marked "battery" on the charge controller. Connect the other end of this wire to the positive terminal of the battery. Repeat this procedure for the other wire, connecting one end to the negative terminal on the charge controller and the other end to the negative terminal of the battery. Remove the cover from the solar panel.

Things You Will Need

  • 12-volt battery
  • Battery interconnect cable (optional)
  • Tape measure
  • Charge controller
  • Insulated copper wire
  • Red marker
  • Wire cutters
  • Basic tools

Tip

  • Many solar panels now come with pre-wired output connectors designed to make connection easier. Common types are called MC3, MC4 and Tyco locking connectors. If the solar panel has pre-wired connectors, contact a qualified electrician to help you to connect the solar panel to the charge controller.

Warning

  • The electricity produced by a single solar panel is not dangerous. But if you are planning on using several solar panels, be much more careful. If you are not sure about how to install the panels, the charge controller and the batteries, consult a qualified electrician.

About the Author

Peter Johnson has managed development programs in Africa and the Caribbean since 1985. Focusing on community management of natural resources, renewable energy and sustainable economic development, he has worked in Djibouti, Sudan, Egypt, Mali, Madagascar, Guinea and most recently in Haiti. He has postgraduate degrees in chemical engineering and fuel technology, as well as protected landscape management.