Originally Posted by riyaraj
1. Turn the WiFi feature off - Whenever you are not using Wireless network or the Amazon kindle Cloud, switch the WiFi feature off to preserve battery power. You can turn off WiFi by tapping the settings bar at the top of the device. Select WiFi and then select the off option.
2. Switch the Kindle Fire to sleep mode -The battery life is primarily used when the device is turned on. If you set the Kindle Fire to sleep mode each and every time you're done reading or watching a film, the battery will be able to last for a couple of days.
3. Adjust brightness - You can also maximize the Kindle Fire's battery life by decreasing the brightness of the screen. Many people may like to read on a dark screen while reading through books regardless of the battery life. To reduce the brightness of the screen, tap the settings bar at top of the screen. After that you can choose brightness and increase or the lower it by sliding the bar.
4. Recharge battery - Another technique to keep your battery power working more time for the future is to only recharge battery power when the power is empty or low.
Number 4 is incorrect. Google lithium polymer batteries and recharging.
With Android there can be a lot of processes and apps running in the background which are not obvious. These can suck down battery over time. So learn which services and processes you don't need and turn them off. that will help quite a bit.