Understanding the Battery Life of Your Mobile Devices

One of the most critical considerations to using a device is its battery life. After all, it doesn’t do a user much good to be in the middle of one of their tasks and their battery dies unexpectedly. To combat this, devices will display the battery life in a status indicator that tells the user how many hours are left for the charge.

However, this number frequently changes. The battery seems to lose and somehow regain hours from its remaining lifespan in mere moments. Or worse, the device will suddenly power down, unable to sustain itself on the remaining power reserves when you thought you still had a half hour left.

If you’ve ever realized that your device is about to die when you’ll need it for a few more hours, then you understand how frustrating this can be. Why is it that the number never seems to be an accurate measure of how long your battery will actually last? The answer to this is pretty simple--your battery has no idea of what you’re going to do next.

The projected battery life gives you the device’s best estimate of how much longer it will last, assuming that you continue using it as you are at that moment until the battery is depleted. Different operations utilize different resources in your device, and will therefore draw different amounts of power from its reserves.

Naturally, this has an effect on the battery’s projected lifespan. Assume for a moment that you’re running a particularly resource-heavy application--your device may estimate that you have another hour of use left. However, once you exit that application, those resources are no longer in use, and you might have four hours left, thanks to the decreased drain on the device’s reserves.

This makes a lot of sense--but what if your device suddenly powers down when it supposedly still has 25 percent of its charge?

This is a sign that it’s time to recalibrate your device, which will reset the hardware’s ability to accurately gauge the battery’s capacity. Many laptops will come with a utility that will calibrate its battery, but it is also possible to do it manually. To do so, follow these steps:

• Charge the battery to 100 percent.
• Let the battery rest for two hours, leaving the device plugged in.
• Go to Power Management Settings and set it to automatically enter sleep mode at 5 percent battery power.
• Unplug the device and let it discharge power until it goes into sleep mode, making sure it isn't set to sleep while idle.
• After it shuts down, allow the device to rest for about 5 hours.
• Plug the device back in and charge it to 100 percent.
• Reset your preferred Power Management Settings.
• Once you have done so, your battery life should be displayed more accurately.

Of course, batteries don’t last forever, either, so if your device still seems to be short on power, it may be time to replace it. While proper care can prolong a battery’s lifespan, it will still eventually degrade. Properly caring for a device’s battery is relatively simple.

Avoid Complete Battery Drains: While older batteries had concerns with “memory,” or the phenomenon of partially discharging and recharging causing a loss in capacity, newer Lithium ion batteries don’t experience this problem. Therefore, there is no reason to allow a battery to drop below 20 percent charge if it can be helped.

Avoid Extreme Temperatures: Heat and cold both have a negative effect on a battery’s lifespan. Do your best to keep devices at a moderate climate, about room temperature.

Leaving/Storing Batteries at Charge Extremes: If your device isn’t going to be used for an extended period of time, try not to leave it either fully dead or fully charged, as either could have a negative effect on the battery. It’s generally considered okay to leave laptops plugged in, but you should unplug it and let the battery run down a little on occasion.

With any luck, following these best practices will keep your devices powered up so you can stay productive. What’s your most frustrating “low battery” story? Share it with us in the comments below.