A truly off-grid power system is a stand-alone, self-contained system that provides electricity. It has no interaction with the electric utility company.

A grid-tied power system is connected to, (tied to) the utility company’s power grid. The most common example is an array of solar panels on the roof of a house. The panels harvest power from the sun and move the electricity thru your house. The excess electricity goes through your electric meter and into the grid. This is how “the meter runs backward”.

Off-grid systems are more complicated and more expensive than grid-tied systems and must have the following components or assemblies:

• Batteries to store and provide the DC electricity.

• An inverter to change the DC electricity to AC electricity so you can run appliances.

• A source of electricity for recharging the battery bank, usually solar panels and/or a generator.

The source of electricity for recharging the battery bank can also be the utility grid. This is called a backup system that is kept fully charged by plugging a battery charger into your regular house outlet. When the grid goes down, you turn on the inverter to run the appliances. When the grid power returns, you use it to recharge the battery bank. Solar panels are not used in this situation. This system is not “grid-tied” because it does not run the meter backward, it is using the electricity from an outlet as if it is a generator.

There are an infinite number of off-grid system designs because they can be premade kits or customized to suit a specific purpose.