Being able to quickly charge your phone or tablet can mean the difference between hours of care-free use or scrambling to find the nearest coffee shop for a power outlet. Fast charging is an increasingly popular feature that allows you to power up your device in just a fraction of the time it takes to do it the old-fashioned way. But not all products use the same type of fast charging—and not all chargers support the various standards. Here’s what you need to know to make sure you’re getting the fastest charge possible.
The output of a charge is measured in amperage and voltage. Amperage (or current) is the amount of electricity flowing from the battery to the connected device, while voltage is the strength of the electric current. Multiplying volts by amps gives you wattage, the measure of total power.
To make a device charge faster, most manufacturers either boost the amperage or vary the voltage in order to increase the amount of potential energy. The majority of fast charging standards typically vary the voltage rather than boost the amperage.