Using a Kill-A-Watt device and examining OS X system information, we can see that the charging profile of the new iPhones match that of the iPad. This allows them to charge using 2.1A. Earlier iPhone models would only draw 5W, no matter the charger used.
Initial tests found that iPhone 6 Plus could be charged in about two hours using the iPad adapter.
Give it a try and let us know if you notice a significant difference in the comments! Please follow iClarified on Twitter, Facebook, Google+, or RSS for more Apple news, tutorials, and videos.
Via: [iLounge] [MacRumors]
[iPhone 5s (left) versus iPhone 6 Plus (right) charging profiles from OS X system report]