Rechargeable lithium-based technology currently provides the best performance for your Apple notebook computer, iPod, iPhone, or iPad. You can also find this standard battery technology in many other devices. Apple batteries share the characteristics common to lithium-based technology in other devices. Like other rechargeable batteries, these batteries may eventually require replacement.
Lithium-ion polymer batteries pack in a higher power density than nickel-based batteries. This gives you a longer battery life in a lighter package, as lithium is the lightest metal. You can also recharge a lithium-ion polymer battery whenever convenient, without the full charge or discharge cycle necessary to keep nickel-based batteries at peak performance. (Over time, crystals build up in nickel-based batteries and prevent you from charging them completely, necessitating an inconvenient full discharge.)
Most lithium-ion polymer batteries use a fast charge to charge your device to 80% battery capacity, then switch to trickle charging. That’s about two hours of charge time to power an iPod to 80% capacity, then another two hours to fully charge it, if you are not using the iPod while charging. You can charge all lithium-ion batteries a large but finite number of times, as defined by charge cycle.
A charge cycle means using all of the battery’s power, but that doesn’t necessarily mean a single charge. For instance, you could listen to your iPod for a few hours one day, using half its power, and then recharge it fully. If you did the same thing the next day, it would count as one charge cycle, not two, so you may take several days to complete a cycle. Each time you complete a charge cycle, it diminishes battery capacity slightly, but you can put notebook, iPod, and iPhone batteries through many charge cycles before they will only hold 80% of original battery capacity. As with other rechargeable batteries, you may eventually need to replace your battery.
Maximum Battery Life
The new iPod touch can play music for up to 40 hours, the new iPod nano can play up to 24 hours, the new iPod classic can play up to 36 hours, and the new iPod shuffle can play up to 15 hours on a full charge at original capacity. Apple runs tests for battery life using songs encoded at 128-Kbps AAC and songs purchased from the iTunes Store (128-Kbps AAC). The songs are played continuously through a playlist without interruption, with backlight and equalizer off. For all iPod models, factory default settings are used except that iPod touch units are associated to a Wi-Fi network and Auto-Brightness is turned off.
A properly maintained iPod battery is designed to retain up to 80% of its original capacity at 400 full charge and discharge cycles. You may choose to replace your battery when it no longer holds sufficient charge to meet your needs.
Let It Breathe
Charging your iPod while in certain carrying cases may generate excess heat, which can affect battery capacity. If you notice that your iPod gets hot when you charge it, take it out of its case first.
Paying attention to just a few commonsense pointers will pay off with a longer battery lifespan and battery life for your iPod. The most important thing is to keep your iPod out of the sun or a hot car (even the glove box). Heat will degrade your battery’s performance the most.
Some Terms You Need to Understand
“Battery life” means the time your iPod will run before it must be recharged (sometimes this is also called “playtime” or “runtime”). “Battery lifespan” means the total amount of time your battery will last before it must be replaced.
Update to the Latest Software
Always make sure your iPod has the latest software from Apple, as engineers may find new ways to optimize battery performance. For instance, early iPod models without a dock connector benefit from update 1.3 or later. Using iTunes 7.4 or later, you can update your iPod with the latest software. Put your iPod in its dock or plug it into your computer and iTunes will notify you if an update is available.
Use iPod Regularly
For proper maintenance of a lithium-based battery, it’s important to keep the electrons in it moving occasionally. Be sure to go through at least one charge cycle per month. If you use your iPod infrequently (gasp), you might want to add a reminder to your calendar program.
Extend Your Battery Life
If you want to extend the battery life of your iPod for any given charge cycle, you may conserve power by following these tips.
Hold and Pause
It may seem obvious, but set the Hold switch when you aren’t using your iPod. This will prevent iPod controls from inadvertently waking up iPod and using unnecessary power. Also, if you are not listening to iPod, pause it, or turn it off by pressing the play button for two seconds.
Optimize Your Settings
There are a few features that use your iPod battery more quickly. If you don’t use these features, your iPod will play tunes longer.
Wi-Fi: Wi-Fi consumes power even if you are not using its features to connect to a network. You can turn it off to save power. Go to Settings > General > Network > Wi-Fi.
Backlight: Setting the backlight to “always on” will significantly reduce your battery life. Use the backlight only when necessary.
Adjust brightness: Dimming the screen is another way to extend battery life on iPod touch. Go to Settings > Brightness and drag the slider to the left to lower the default screen brightness. In addition, turning on Auto-Brightness allows the screen to adjust its brightness based on current lighting conditions. Go to Settings > Brightness and set Auto-Brightness to On.
Equalizer: Adding EQs to playback uses more of your iPod processor, since they aren’t encoded in the song. Turn EQ off if you don’t use it. If, however, you’ve added EQ to tracks in iTunes, you’ll need to set EQ to “flat” in order to have the effect of “off,” because iPod keeps your iTunes settings intact.
Minimize use of third-party applications: Excessive use of applications on iPod touch, such as games that prevent the screen from dimming or shutting off, can reduce battery life.
Fetch new data less frequently: Applications on iPod touch such as Mail can be set to fetch data wirelessly at specific intervals. The more frequently email or other data is fetched, the quicker your battery may drain. To fetch new data manually, from the Home screen choose Settings > Mail, Contacts, Calendar > Fetch New Data and tap Manually. To increase the fetch interval, go to Settings > Mail, Contacts, Calendar > Fetch New Data and tap Hourly. Note that this is a global setting and applies to all applications that do not support push services.
Turn off push mail: If you have a push mail account on iPod touch such as Yahoo!, MobileMe, or Microsoft Exchange, turn off push mail when you don’t need it. Go to Settings > Mail, Contacts, Calendar > Fetch New Data and set Push to Off. Messages sent to your push email accounts will now be received on your iPod touch based on the global Fetch setting rather than as they arrive.
Turn off push notifications: If you have apps installed on iPod touch that use push notifications, you can turn them off for some or all apps. Go to Settings > Notifications and set Notifications to Off to turn off all push notifications. The push notification settings for each app also appear here. Select the app and set specific notifications to Off.
Maximize Your Memory
iPod plays music out of a solid-state memory cache to provide skip-free playback and maximize battery life. iPod spins its hard drive to fill this cache, which uses power. A couple of factors affect how often this happens, and if you minimize these factors, you’ll extend battery life.
Limit Fast-Forwarding: If you fast-forward through your playlist, iPod has to fill its cache more frequently, thus accessing the hard drive more often and using more power. This decreases overall battery life. By creating great playlists in iTunes that cater to your personal taste, you can decrease your need to fast-forward. Using the shuffle feature may also help to minimize your use of the fast-forward feature.
Use Compressed Songs: The iPod cache works most efficiently with songs of average file sizes (less than 9MB). If your audio files are large or uncompressed (including AIFF or WAV format), you may want to compress them, or use a different compression method, such as AAC or MP3, when importing them into iTunes. Also, consider breaking very long songs or tracks into shorter tracks that have smaller file sizes. If you encode your music at 128 Kbps, your iPod will fill its cache about every 25 minutes.http://www.apple.com/batteries/ ;http://www.apple.com/batteries/ipods.html