Battery Type

• The Apple iPhone comes with a standard lithium-ion battery. These batteries are becoming the battery of choice for electronic devices due to their power, lifespan and ease of use. Unlike nickel-based batteries, for example, users don't need to be concerned with the "memory effect" -- a reported condition which causes the battery to lose its capacity when it doesn't complete full charge and discharge cycles. What this means is that you do not have to charge your device to 100 percent every time and worry about damaging the internal battery.
  
  

Lifespan

• The typical lifespan of a lithium-ion battery is between 300 and 500 charging cycles. That means if you're charging your iPhone fully on a daily basis, you'll need to replace the battery in your phone within 12 to 18 months. If your battery only completes a full charge cycle every two to three days, your battery should last twice as long.
  
  As a general rule of thumb, it's time to replace the battery in your iPhone when its capacity decreases by about 50 percent. Therefore, when you find yourself needing to charge your phone twice as often, it's time to schedule a replacement.
  
  

Battery Care

• Although there is nothing you can do to prevent the gradual deterioration of your iPhone's lithium-ion battery, there are steps you can take to maximize its life. Some important considerations include avoiding extreme temperature shifts, turning your phone off when it's not in use and preserving the length of each charge. Some tips for preserving the length of each charge include: minimizing energy-draining applications, turning off Wi-Fi when it's not in use and turning off push notifications.
  
  

Charge Cycles

• The average lifespan of the lithium-ion battery in your iPhone is calculated by full charge cycles. Therefore, if you only charge your phone halfway, that only counts as half a charge cycle. Apple recommends that you charge your iPhone to 100 percent then completely draining it once a month to help maintain the battery.