The iPhone 6 Plus was discovered to have a huge 2915 mAh battery inside. The smaller iPhone 6 naturally has a smaller power storage unit, at 1810 mAh, but it's still much bigger than the 1560 mAh battery found on the 4-inch iPhone 5s. The battery also seems to be slightly confused about its energy rating. On one side it says 6.91 Wh but the other side says it had a 7.01 Wh rating. As iFixit itself says, "Perhaps the engineers were able to squeeze an extra 0.1 Wh in the battery after confirming the text on the front."
You can check out the rest of what iFixit found inside the iPhone 6 on their site. What do you think about the hardware inside the smaller version of Apple's latest smartphone?