One of the features overlooked about the iPhone 5S is the bigger battery. It’ll lead to longer usage times despite the more powerful A7 processor. You’ll be able to get up to 10 hours of 3G talk time and 10 hours of LTE Internet usage (not combined). The other areas of usage have a similar battery usage to the old iPhone 5. Standby time has been improved from 225 hours to 250 hours.
The battery in the iPhone 5S is slightly larger and offers nearly 10 percent more capacity (probably why standby time has increased by 10 percent). The A7 processor is also supported by a new dedicated motion tracking chip which makes it more efficient when dealing with motion tracking. Things like fitness apps will be usable for far longer.
Apple tested the devices in August using preproduction models and software. Testers turned off auto brightness and “Ask to Join Networks.” So you might not get all the battery life it claims in regular usage. Still, it sounds pretty good in comparison to other devices.