Can You Power Your Garmin With a USB Cord?by Fred Decker
Most modern GPS devices from major manufacturers such as Garmin come equipped with a USB cable. It's primarily intended for connecting the GPS to a computer, enabling users to install or back up new maps, points of interest, and tracks or routes. Garmin devices with a built-in charging circuit can also trickle-charge from the USB connection, which is slow but will extend the battery life. The supplied USB cable won't power the GPS directly, but there are alternative methods.
Standard USB cables use a four-wire connection to transfer data and low-voltage power between devices. The tiny micro-USB connectors used by cell phones, GPS devices and other compact electronics have a fifth wire. It's not connected between the devices, but is used instead for a small circuit that determines how the multi-purpose connector is used. This is what tells your Garmin device whether to use the USB connector for data, power or charging. Garmin's own supplied cable works for data transfer or trickle-charging. Generic USB cables will perform data transfer only. Powering the Garmin requires an AC or DC power supply with a micro-USB connector, or a specialized USB power cable.
AC Power Adaptors
Garmin's product line includes a range of power supplies designed to plug into AC or DC outlets and provide the 5-volt DC input required by the handheld device. These fall into three basic categories. AC adapters consist of a small block to plug into the wall outlet, and a cable with a micro-USB connection at the end for the GPS. North American models have a U.S.-style plug and accept 120-volt input. International models accept either 120- or 240-volt input, and have the European-style two-prong plug built in. Adapters for other plug arrangements, including three-prong North American plugs, are included.
DC Power Cables
DC power cables are available from Garmin in two styles. One has the familiar oblong 12-volt cigarette lighter plug at one end, and a micro-USB connection at the other. Its built-in circuitry steps down from 12-volt DC to 5-volt DC to power the GPS device. The second style of power cord has bare wires at one end, and can be wired directly to the car's fuse block or spliced into its electrical system. The other end has a standard micro-USB connection for the GPS device. These cables are intended for permanent installation in your vehicle. Some will power your GPS, but others are intended only for charging.
Various companies manufacture aftermarket chargers and cables for Garmin GPS devices. Many compete on price, offering similar functionality at a lower cost. Others address niche markets or resolve specific problems. For example aftermarket cables might offer connectors at unusual angles, enabling users to accommodate a power cable in their favorite mounting bracket. Others offer special features such as weatherproofing and splashproofing, protecting the GPS and its power connection while hiking, cycling or riding off-road vehicles.