Solar Electricity

Electricity, Made In Your Own Home

When sunlight hits the photovoltaic cells in your solar panels, they generate solar electricity that you can use.

In strong sunlight and with no load to the circuit, it is not uncommon for a 12 volt solar panel to pump out 18 volts or more of DC electrical current. Small solar-powered electric pond pumps are typical of the simple solar-powered electric systems which work in this manner.

And while those systems are designed to handle higher voltages without complaint, most domestic electric systems will not. The over-voltage can fry the delicate circuitry in most electronic devices, such as radios, TV sets and home Hi Fi systems.

So you need to tame the beast (solar electricity). That's all very well, you may say, but how to achieve this?

The first way is to use rechargeable storage batteries in your circuit. This has two advantages:

1. Having a storage battery in the circuit limits the maximum voltage seen in the circuit. So while the panel may put our 18 Volts DC, the battery will only put out a maximum of 13.8 volts, or thereabouts. (The exact voltage depends on the type of storage battery, and also on its state of charge or discharge.) Typical rechargeable battery types include lead acid, gel cell, Nickel Metal Hydride (NIMH) and others.
2. Having a storage battery allows you to make use of that stores electricity even at night or while the sun is obscured by heavy clouds. Now you can have solar electricity available 24 hours a day, 7 days a week.

Of course, you will need enough solar panels to gather slightly more power each day than you will use. Otherwise the storage battery will be run flat, and will be unable to recharge sufficiently — even when the sun is shining. The result will soon be a dead battery you cannot recharge or revive.

The life of your storage batteries will also be extended if you place a regulator into the circuit to ensure that your rechargeable storage battery (or bank of storage batteries) is never over-charged. You also want to make sure your storage batteries are never over-discharged, for that too will kill them off.

Next: Battery Regulator