The electrical system in your car, in most cases, provides 12V DC, which is different from the AC power you use at home. The options for powering devices in a car include using an existing cigarette lighter outlet (also known as a 12V accessory outlet) or installing a power inverter. The primary methods of using 12-volt car power to run your electronic devices on the road include 2V adapter and hard-wired plugs, universal 12V USB adapters, and car power inverters.
Using 12V DC Outlets to Power Electronics
The easiest way to power an electronic device in your car is via the cigarette lighter receptacle or a dedicated 12V accessory outlet. One of these two types of 12V sockets is available in almost every modern car and truck. As the name implies, these sockets started as cigarette lighters, which worked by applying current to a coiled metal strip. This current flow caused the coiled metal strip to become red hot—hot enough to light a cigarette on contact. It didn’t take long for inventive minds to find another use for cigarette lighter sockets, which are now also known as 12V accessory outlets. Since the sockets apply battery voltage to the center contact and ground to the cylinder, according to ANSI/SAE J563 specifications, 12V devices can be powered by a plug that makes electrical contact with those two points. The standards are a little different from one part of the world to another, and the specifications for a cigarette lighter socket and a 12V accessory socket aren’t precisely the same. Still, 12V plugs and adapters are designed to work within a range of tolerances. The fact that these sockets originated as cigarette lighters and the corresponding sloppy tolerances means potential issues can arise from using them as power sockets. Today, some cars ship with a plastic plug or USB outlet in the dash instead of the traditional cigarette lighter. Some sockets are physically incapable of accepting cigarette lighters, often because they’re too narrow in diameter or too shallow. Plastic plugs are also available via the aftermarket for owners of older vehicles who prefer not to have a cigarette lighter in their car.
Powering Devices With Built-In 12V DC Plugs
While a cigarette lighter or 12V accessory outlet is the easiest way to power an electronic device in a car, the situation is simplified if the device has a hard-wired 12V DC plug. These devices are designed for use in cars, so you typically don’t need to worry about power consumption or blowing fuses. Devices that sometimes ship with hard-wired 12V DC plugs include:
CB radios GPS units DVD players Video systems Plug-in inverters
Powering Devices With 12V DC Power Adapters
Devices that don’t have hard-wired DC plugs sometimes have 12V DC adapters or are compatible with adapters that you can buy separately. GPS navigation units, cellphones, tablets, and laptops often fall into this category. And while you do have to be careful about how much amperage you draw with these devices, it’s still a relatively simple plug-and-play solution. Devices that are often compatible with proprietary 12V DC adapters include:
Cellphones Laptop computers GPS units DVD players LCD screens
Powering Devices With 12V USB Adapters
In the past, 12V DC adapters used a variety of incompatible plugs in addition to a range of voltage and amperage outputs. This was particularly true of the cellular phone industry, where two phones from the same manufacturer often required different DC adapters. Many phones and tablets have moved toward using the USB standard instead of proprietary connectors in recent years. That means that most modern devices can use generic 12V USB adapters for power. Common devices that can use 12V USB adapters include:
CellphonesTabletsGPS unitsFM broadcastersBluetooth hands-free devices
Powering Devices With 12V Car Power Inverters
Although car power inverters are more complicated to use than 12V adapters and plugs, they are also more versatile. Since these devices convert 12V DC power to AC power (the electricity from a standard wall plug), they can be used to run most electronic devices off car power. Whether you want to plug in a crockpot, dry your hair, or microwave a burrito in your car, you can do it with a car power inverter. There are inherent limitations involved when working with car inverters. First, the simple ones that plug into a cigarette lighter or 12V accessory outlet are limited in their utility. Since cigarette lighters are typically wired with 10A fuses, you can’t power a device via a plug-in inverter that draws more than 10 amps. Even if you wire an inverter directly to the battery, you’re limited by the alternator’s maximum output. If you want to run a device using car power, and it’s not listed in the categories above, a car power inverter is your best bet. Consider how much power you need and the amount of power that your electrical system can produce. Although the power for your electronics comes from the alternator whenever your car is running, the battery is the source when the engine is off. If you want to run your devices when you aren’t driving, consider installing a second battery. In some cases, it can be helpful to add a cutoff switch to the main battery to prevent your electronic devices from draining it while the car is parked.
