I’m interested in the possibility of using my son’s video game console (with a small TV) in our SUV during vacation trips. It’s my understanding a power inverter can be plugged into the cigarette lighter to power these things. Can you please shed a little light on how these can be used?

Morris Talbot, San Jose, Calif.

Power inverters have become quite popular with on-the-go folks, and, in really large applications, have even replaced gasoline-powered generators. These devices convert 12 volts DC into 115 volts AC power, which is needed for most household devices.

Small inverters, up to about 300 watts, can be plugged into a vehicle’s lighter socket, while larger inverters require a direct connection to the battery.

Choosing the right inverter requires a bit of planning. You’ll need to add up your anticipated electrical usage, factor in a safety margin and determine if a modified sine wave or true sine wave inverter is best for your needs. The power requirement of most AC devices can be found on a specification sticker or plate, generally on the back or bottom of the device, and is listed in either watts or amps at 120V AC. To convert amps to watts, multiply by 120.

It’s important to remember appliances containing inductive motors, such as refrigerators or pumps, can draw as much as three to five times their normal consumption during start-up.

Most inverters are rated by continuous power and surge (start-up) power – be sure your usage falls at least 10 to 20 percent below these values.

One final fly in the ointment: Inexpensive and moderately priced inverters produce a modified sine wave. This refers to the manner in which the current alternates back and forth. A modified sine wave inverter cleverly imitates the smooth curve of true AC power with a series of rectangular steps. This works well for most appliances, but can cause interference or operational problems with sensitive electronic devices such as computers, TVs, variable-speed control tools, fluorescent lights and, you guessed it, game consoles. True sine wave inverters are available in a wide range of sizes, although at about double to triple the cost of their less sophisticated peers.

A properly chosen and installed power inverter can be a marvelous addition to a vehicle, and might one day become standard equipment. Your planned usage appears to slightly surpass the lighter socket inverter category. The 12-volt cables connecting larger inverters to the battery must be large in diameter and as short as possible, and adequate ventilation and protection is needed for the inverter.

One important consideration is battery depletion, if operation is planned while the vehicle is parked. If this is likely to occur for more than brief periods, you should add a second, deep-cycle battery, with an isolation device. Occasional operation of the engine is also needed to recharge the battery, perhaps 10 minutes for each hour of use, more so for larger loads. Check out www.donrowe.com.

Brad Bergholdt teaches automotive technology at Evergreen Valley College in San Jose, Calif.

E-mail him at under-the-hoodjuno.com or write to him in care of Drive, Mercury News, 750 Ridder Park Drive, San Jose, Calif. 95190.)

—

(c) 2005, San Jose Mercury News (San Jose, Calif.).

Visit MercuryNews.com, the World Wide Web site of the Mercury News, at http://www.mercurynews.com.

Distributed by Knight Ridder/Tribune Information Services.

AP-NY-07-15-05 1424EDT