My G1 ran out of battery again last night? Insane, it was at 80% when I went to sleep on the new battery. What is it doing?

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 have a high power density that gives you a long battery life in a light package. And you can recharge a lithium-ion polymer battery whenever convenient, without requiring a full charge or discharge cycle. 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.

Rechargeable batteries have a limited number of charge cycles and may eventually need to be replaced and disposed of. For products with built-in lithium-ion polymer batteries, the batteries should be replaced only by Apple or an Apple authorized service provider. Apple and its authorized service providers will ensure the spent battery is recycled properly, since batteries should always be recycled or disposed separately from household waste.

Once an Apple product reaches the end of its useful life, Apple will help you recycle it responsibly. The length of time your battery will power your device depends on how you use it. For instance, watching a movie or playing a game will use up your notebook battery’s power more quickly than simple word processing.

You can follow some easy steps to maximize your notebook, iPod, iPhone, or iPad battery life.