Testing the battery of your Kindle Fire HD can give you valuable information regarding how to best use the device. Knowing, for example, how long the Fire will run if you’re playing videos through the entire battery lifespan allows you to plan activities for a long flight or road trip. Make sure to test the battery life available under a variety of different circumstances, as time between charges varies dramatically depending on your daily tablet activities.

Regular Use Test

The first method for testing your Kindle Fire HD’s battery life is simply charging it to full capacity, making a note of the time and date you disconnect the charger, and then using the device as you normally would; however, instead of charging it again when the battery gets low, allow it to completely deplete and power down. This gives you a good idea of how long the Kindle Fire HD will last under normal usage. Once you have a baseline, it’s easier to compare the results of more intensive testing. You should be able to get about seven hours of use out of the Kindle while browsing the Web, navigating apps and listening to music.

Wi-Fi Disabled Testing

One of the most notorious battery drainers for tablets like the Kindle Fire HD is the device’s use of Wi-Fi connectivity. Connecting to and relying on a Wi-Fi signal increases battery drain, and if the device is constantly looking for a connection when there is none, it can put additional stress on your existing charge. Disable Wi-Fi on your Kindle Fire HD and use it as normal to get an idea of how much battery power you can save. This is a good strategy for long road trips; because there’s no reliable Wi-Fi connection, you’ll avoid draining the battery unnecessarily. Turning off Wi-Fi on your Fire should result in noticeable benchmark improvements under any usage circumstance.

Watching Movies

If you use your Kindle Fire HD as a portable entertainment system, you’re going to want to know how long it can sustain a charge under the heavy load of playing back video content -- you don't want your device to shut down mid-movie. Start from a full charge and play the longest movie you own. When the movie hits the credits, start it over again. Repeatedly run the movie until the battery runs out of charge to learn how many hours your Fire will play video content. Benchmarks for the Kindle Fire HD indicate that the device should run for about six hours while streaming video content.

Saving Battery Life

Your Kindle Fire HD continues to use battery power even when you’re not actively interacting with the device. If not powered down, the device enters a standby mode that keeps bare system elements running and remembers which apps you were using or what content you were viewing. To extend the Kindle Fire HD’s battery life as far as possible, shut it down completely between uses. Note that this strategy isn’t necessary unless you’re preparing to go a long period of time without access to a charging point. The Kindle Fire HD takes just over three hours to reach a full charge when connected to an AC outlet.