You might think that all chargers are created equal, but nothing could be further from the truth. Wired explains that picking the right charger with the right amperage (a measure of current) can mean the difference between getting your phone charged while you work versus waiting all day before you can unplug it.
Photo via Alex Washburn
This isn't as simple as "charge your device with the charger it shipped with". You can actually use higher amperage chargers, like the kind that come with tablets, to charge your phone in less time than it would if you charged via USB or using the charger the phone came with, and it won't cause a problem. Here's how it breaks down:
For example, consider these charging scenarios for the Retina iPad mini. You could use a Lightning connector plugged into a computer (via USB), an iPhone charger connected to a wall socket, or an iPad charger connected to a wall socket. A PC USB charger delivers 2.5 Watts of power (5 volts at 500 mA). An iPhone charger delivers 5 Watts (5 volts at 1000 mA). A Retina iPad mini charger delivers 10 watts (5.1 volts at 2100 mA).
While all of these will charge your iPad, using the USB connected to a PC will charge your Retina mini four times slower than if you used the iPad charger it came with. Conversely, if you use the iPad charger for your iPhone, it'd charge up faster than normal. If you play mix-and-match with these types of chargers like this, don't worry — you're not going to blow up your phone or anything crazy like that. And the myth that charging your device at a faster rate will reduce the life of your device's battery is false. For some older devices, the higher specced charger just won't work at all, while newer devices will just charge faster.
Ultimately, it's really the amperage that determines how fast a charger will supply power to your device. If you want quicker charging, look for a wall or car charger that delivers 2100 mA of current at 5 volts (or whatever voltage the device you're trying to charge is specced at).
The lesson? Look for reliable chargers that offer high amperage and use the same connectors as the device you're trying to charge. If you have a high amperage charger, you can cut down on your overall charging time.