Apple is said to be moving to use more powerful batteries this time around for the iPhone 6 that pack more of a punch. The larger battery is necessary for the 5.5 inch screen for sure, but the added power on the 4.7 inch model would be an eight percent jump over the current battery.
According to the rumors we are hearing from our sources, the 5.5 inch screened iPhone 6 model will sport a 2500 mAh battery, while the 4.7 inch model will use a 1800 mAh battery.
We are not sure that you are actually going to see more run time battery life out of the 5.5 inch unit, but the 4.7 inch unit should enjoy a bit longer run time.