iPhone FAQ : Technical Specifications > Battery
- How do I charge it?
- iPhone is charged in its Dock, which takes power from the computer's USB port. Chargers with Dock connectors should work.
- How long does a battery charge last?
- The following table lists Apple's battery life claims.
Apple provides testing notes for each mode:Talk Time Up to 8 hours Standby Up to 250 hours Internet Use Up to 6 hours Video Playback Up to 7 hours Audio playback Up to 24 hours Source: Apple iPhone Technical Specifications
Talk Time and Standby: All talk time testing was done connected to a 1900MHz network. All settings were default except: Call Forwarding was turned on; the WiFi feature Ask to Join Networks was turned off.
Internet: Internet over WiFi testing conducted using a closed network and dedicated web and mail server, simulating browsing to 20 popular URLs and checking mail once an hour. All settings were default except: Call Forwarding was turned on; the WiFi feature Ask to Join Networks and Auto-Brightness were turned off; WPA2 encryption was enabled.
Video: Video content was a repeated 2 hour 23 minute movie purchased from the iTunes Store. All settings were default except: Call Forwarding was turned on; the WiFi feature Ask to Join Networks and Auto-Brightness were turned off.
Audio: The playlist consisted of 358 unique audio tracks, a combination of content imported from CDs using iTunes (128-Kbps AAC encoding) and content purchased from the iTunes Store (128-Kbps AAC encoding). All settings were default except: Call Forwarding was turned on; the WiFi feature Ask to Join Networks was turned off.
Finally, on all tests Apple adds the following disclaimer: Battery life depends on the cellular network, location, signal strength, feature configuration, usage, and many other factors. - Is the battery removable?
- No, iPhone has a built-in, inaccessible battery like iPods.
- Is the battery replaceable?
- Not by end users. Apple offers a battery replacement service for about $85. Apple offers a rental iPhone for $29 for the duration of the service.
- How long until the battery needs replacement?
- All batteries degrade with time and use. Apple says the battery is designed to provide 80% of its original capacity after 300 to 400 charge cycles. Its usable lifespan will depend on usage; heavy voice/internet users will require battery replacement sooner than occasional users. (See Apple Battery Info Page for additional information and the definition of a "cycle".)
- How should I maintain my battery? Do I need to perform "deep discharge"?
- iPhone uses a lithium-ion battery, like iPods and Apple's laptops. "Li-ion" type batteries are immune to the "memory" effects of earlier battery technology, and can be charged at any point without harm. A periodic full discharge and recharge can help the battery's power circuitry remain well-calibrated to provide an accurate estimate of remaining power (and runtime). (Li-ion batteries actually can be harmed by "deep discharge" maintenance techniques used for earlier Ni-Cad and NiMH batteries if run to completely empty, but circuitry inside the battery provides some protection against this by maintaining a small reserve. Simply charge your battery as soon as possible after fully discharging it to avoid this.)
- How long does it take to charge iPhone?
- When plugged into a computer's USB port, iPhone appears to trickle charge and can take six or eight hours to fully charge. When plugged into its power brick, iPhone appears to charge rapidly and fully recharges within a few hours.
- How can I maximize iPhone's time between charges?
- Apple provides advice for maximizing iPhone's battery life. For best runtime, turn off WiFi and Bluetooth when not using them, disable the music equalizer (set to "flat" to override iTunes's settings), enable Auto-Brightness (which dims the screen when appropriate), and keep iPhone's temperature below 95° F (30° C). (Apple says 72°F / 22° C is ideal.) If iPhone gets hot while charging inside a case, remove it from the case while charging. (Overheating a battery can permanently damage it, vastly reducing its capacity.)
(We have found Bluetooth is particularly demanding of mobile phones' tiny batteries. iPhone's included wired headset uses much less power than what is required to support a wireless Bluetooth headset.)
