One of the few accessories included with the iPad is a USB Power Adapter, which will charge the device from a wall outlet. All wall chargers are the same, right? Unfortunately, no.
If you look closely at the specs on the adapter, you’ll see different amp ratings depending on the model of iPad you have. The iPad Air, 9.7″ iPad Pro and iPad Mini 3 and 4 come with a 10 watt, 2.1 amp charger. The iPad 4 and the 12.9″ iPad Pro include a 2.4 amp charger. The original iPad Mini, iPhone and iPod Touch all come with a 1 amp charger. The difference between 2.1 and 2.4 amps isn’t worth worrying about, so we’ll just call them 1 amp and 2 amp chargers.
The full-size iPads have large screens, which require a large battery to deliver that great battery life (this is especially true for Retina display iPads). The higher 2 amp charger allows, the larger battery to charge more quickly than when using the traditional 1 amp adapter. It will take around 4-6 hours to charge a completely drained iPad battery, depending on the model.
Setting up "charging stations" where your iPads can keep being charged when not in use is recommended. Having a "Home base" is a great way to reduce misplacing you devices.
NOTE: 2 amps won’t hurt your iPad Mini or your iPhone, but 1 amp won’t be enough for your iPad.