Originally Posted by scorchedsky
With the included AC adapter, the S5 can charge at up to 2.1 amps or so. USB 3.0 maxes out at 1.0 amp, and wireless chargers are about 0.7 amp. The slowest is really USB 2.0, which is only like 0.45 amp.
A good and essentially correct summary. But there are exceptions and cavets.
While most USB 2 ports are rated at ~ 0.5A it varies and newer notebooks in particular may have USB 2 ports capable of 1A +.
Most AC adapters (aka travel adapters ) are typically, either 0.7 or 1A. But a decent full size AC adapter will be ~ 2A.
Also note that the phone will limit it's current draw when using a standard data cable so as not to overtax an USB port. To maintain a maximal charging rate when connected to a high capacity USB 2 port or USB jack on an AC adapter, a "charging" or power cable should be used. A charging cable has the two data lines shorted, to let the phone know that you are (ostensibly) connected to a high current source, rather than a standard USB 2 port.
And wireless chargers vary substantially in maximum output current from ~ 0.3 to ~ 0.9A. Most are also sensitive to ideal positioning. A randomly placed phone may charge at a substantially reduced rate, due to the reduced coupling efficiency of a random orientation.