According to her supply-chain sources, the 4.7-inch iPhone 6 might actually sport a larger 2,100 mAh battery as opposed to a 1,810 mAh unit. Reportedly, the 1,810 mAh battery we’ve seen in the aforementioned leaked picture is as real as it can be, but according to Sung Chang Xu’s sources, these units have been used solely for testing purposes.
It should be noted that GforGames specializes in quoting every Chinese source going, and even the source doesn’t appear too confident in this case, so we’re not putting much stock in it.
The battery-life of the iPhone 6 is an interesting question. Assuming the many leaked case parts are real, the phone will be significantly slimmer than existing models, and it’s likely that this will be achieved in large part by a thinner battery. The larger, higher-res screen will also use more power.
However, the larger form factor of the phone will allow the battery to be both longer and wider, and it’s also likely that Apple will further improve the power efficiency of the phone. If I were to guess, I’d say that Apple will aim to cancel out these effects in order to match the battery-life of the iPhone 5s in the 4.7-inch model, but there’s still room to hope for an improvement.