I found this cool post on iPodTouchFans with all these tips on how to preserve your iPod Touch/iPhones battery.
- Top up the charge frequently! Charge your device often to prevent rapid erosion of the Lithium-ion battery’s capacity. Never let your battery run down to zero. Your battery will fast charge for 1.5 to 2 hours to reach 80% charge and then trickle charge for 2 to 3 hours more to reach 100%, so try to charge a weak battery for at least 2 hours. Lithium-ion batteries lose capacity as soon as they are manufactured but a properly maintained battery is designed to retain 80% of its capacity after 400 charge & discharge cycles.
- Recalibrate Your Battery Meter – If you charge your device regularly and also use the ‘Numerical Battery’ you may want to consider running down the battery once per month followed by a full charge. The battery meter tracking the battery’s capacity will lose accuracy over time and this full discharge will recalbrate it. If you use the stock Apple battery icon then there’s probably no need for such accuracy unless you start to get strange readings.
- Keep your iPod Touch cool! Lithium-ion battery capacity rapidly decays if exposed to high temperatures. Don’t leave your device in the car. Maximum operating temperature suggested is 35° C (95° F). Don’t charge when hot as this can further damage the battery’s capacity. Remove any cover/skin when charging to help prevent overheating.
- Maintenance in storage – If your don’t use your device regularly, make sure you complete one full charge cycle per month. This can be staggered, e.g. use 50% of battery, charge full and then use 50% again. When not in use store your device below 45° C (113° F) to prevent heat damage to the battery’s capacity.
- Stay updated – new firmware and software updates often include more battery-efficient code so update and keep current if you can.
- Manage Your Apps – conserve your current battery charge by turning off 3G, WiFi, Edge, SSH and/or Bluetooth when not in use. Other functions such as GPS & Push Email will also cause the battery to drain faster. Turn off the WiFi function ‘Ask to Join Networks’ as this can leech the battery. Update email manually. Use ‘Airplane Mode’ in areas of low coverage to prevent continuous scanning draining the battery. Turn off ‘Location Services’ in Settings when not in use. Hold the home button for 5 seconds to kill any applications running in the background.
- Equaliser – turn the EQ off if you don’t need it.
- Backlight – Turn the brightness down as low as possible (~25% is good) and enable ‘Auto Brightness’.
- Screen Lock – Use a short ‘Auto Lock’ time. Turn the screen off whenever it’s not in use by a quick press of the power button.