Lighting Systems

In home power sytems, there are two main types of lighting utilized - low voltage and high voltage.

Low voltage lighting is powered directly by the batteries. The advantages of this type of system include:

High efficiency: Using low voltage flourescent and halogen bulbs, satisfactory results can be obtained with very little electricity. Reliability: With a DC lighting system, the lights can be operated until there is no more electricity in the battery bank. Period.

Disadvantages:

In houses with an AC wiring system, separate wiring runs must be made for the DC lights. Long wire runs must use a heavier guage wire than their AC counterparts. DC lightbulbs and compatible fixtures are more limited in variety and typically more expensive than AC types. DC lightbulbs are not as readily available as 120V AC bulbs. in many areas, replacement bulbs must be ordered in.

High voltage lighting utilizes an inverter connected to the battery bank to provide the required voltage. Although this type of lighting has many advantages, having the electricity conditioned by the inverter on the way to the fixtures wastes 5 - 20% of the energy right off the top. In many larger systems this loss is tolerable because of the prohibitive cost of installing a separate large DC wiring system, but in small systems it is often wise to use DC for lighting.

The advantages of AC high voltage lighting include: There are a wide variety of readily available lamps and fixtures located in your local hardware store. Easy installation using off the shelf components. Easy code compliance Components for AC wiring systems are relatively inexpensive. Long wire runs are no problem.

Disadvantages: Relatively lower efficiencies than DC systems In an otherwise all DC system,installation of AC lighting would require the purchase of an inverter.

In a nutshell

DC lighting is preferrable in small systems, but AC usually proves more cost effective for medium to larger systems.