Eventually, as the battery gets older, you’ll begin to notice that your iPhone or iPod touch has to be recharged more frequently. When you’re no longer comfortable with this, it’s time to replace your battery.
The “lifespan” of the battery refers to the number of times in can be recharged before it must be replaced. The batteries on the iPhone and iPod touch slowly lose the ability to hold a charge after numerous recharge cycles. For example, after 400 full discharge/recharge cycles these batteries are able to store 80% of their original capacity. This percentage decreases with further recharge cycles. There are things you can do to improve the lifespan of the battery:
According to tests by Apple, an iPhone with a fully charged battery will provide up to 8 hours of talk time, 250 hours of standby time, 6 hours of Internet use, 7 hours of video playback, and 24 hours of audio playback. An iPod touch with a fully charged battery can play music for up to 22 hours and video for 5 hours. There are certain things you can do to improve the battery life: