How to live large on every battery charge

These handy tips will help you wring every last watt-minute out of your laptop and other mobile devices.

While it's easier to find outlets for charging your mobile device in vehicles and public places these days, there will always be the occasion when you need to nurse the battery in your laptop, smartphone, or tablet because you can't charge it. Whether you forgot bring your charger, are stuck in the woods, or you simply want to revel in the un-tethered-ness of it all, here are some tricks for achieving longer run time.

Increase the run time on any device

Fact: your battery has a set amount of juice in it, and there's not a darn thing you can do to increase it (safely anyway). Ask Boeing, or Tesla CEO Elon Musk.

So if electrical capacity is finite, it's pretty obvious you'll need to reduce consumption to make it last longer. The only way to do that is to turn things down or off, just as you do with the lighting and appliances in your house. You knew that, but maybe you didn't know just how much stuff there is to turn down or off.

The most obvious component that you can turn down, and leave off when not in use, is the display. Reduce the brightness as far as you can, and turn it off whenever you don't need it. Reduce the automatic shutoff setting. The more aggressive you are the more power you'll save. If you're in dire straits, manually shut it off as quickly and as often as possible.

The GPS circuitry and the real-time navigation software that use it are the most notorious power sucks in mobile devices such as smartphones. They stress not only the radio, but the CPU with graphics. If you're low on juice, memorize the general location and route, and then wait until you're close before you go crazy with the GPS app. Stick with just the voice cues if you can.

Bluetooth, cellular, NFC (near-field communication), and Wi-Fi radios are also major power drains. Turning these off when you don't need them can double your battery life. Airplane mode, which turns them all off, is intended to save your battery, which drains very quickly when your phone constantly is searching for signals that are non-existent at 35,000 feet. Note: if you have a phone that supports Wi-Fi calling (T-Mobile/Windows Phone 8), using the feature will increase battery run times, because the Wi-Fi radio uses less current.

Finally, while multitasking makes switching between apps quicker, it also uses more power. Even if an application isn't front and center, it still has to be serviced by the operating system, and it might be performing tasks in the background. Run only one app at a time when you're low on battery.

Tips for laptop users

So far, everything I've already discussed applies to any mobile computing device; however, there's a lot more you can do when the device in question is a laptop. In addition to dimming your display and turning off radios, there's a host of other hardware you can turn off, such as the back-lit keyboards, Firewire ports, Wi-Fi, serial and com ports, Web cams, sound and auxiliary video controllers, and your optical drive (if you laptop even has one). The power savings when disabling any one device might not be great, but disable a bunch and it can make difference.

To disable any piece hardware component that allows it (CPUs and drive controllers can't be), type "device manager" using the Windows find function (the box at the bottom or the Start Menu, or simply typing in Metro), or right-click on Computer, select Manage, and open Device Manager from the tree on the left. Right-click on any item to disable or enable it.

Then there's the software. Oh, the software. I already talked about running only one application at a time, but applications are only the tip of the iceberg. You might be running dozens of convenient, but unessential background processes. Prime examples are software updaters, printer and scanner control panels, and online storage service apps. There are even a number of Windows features--such as search indexing--that can be disabled. To kill unnecessary processes, use the Windows find function as described above. But this time, type "task manager." Alternatively, right-click on the taskbar and select "Start Task Manager", or press Ctrl+Alt+Del and select the same thing. Once the Windows Task Manager dialog appears, select the "Processes" tab and peruse the process names and descriptions.

Generally speaking, you can safely kill any process with a third-party brand name in it (Adobe, Apple, Dell, Google, HP, Dell, etc.). Right-click over the program and select End Process Tree to kill it and any non-visible processes that it spawned. Don't worry, you're not doing anything permanent here, the process will reappear after you restart or log off and log in again. Hopefully, the time you take disabling stuff doesn't drain more juice that leaving them running will. It pays to familiarize yourself with this culling while your laptop is running on AC power, so you can do it quickly when it counts.

If you wish to disable background apps and processes so that they don't automatically return at restart, run msconfig.exe (use the Windows find function). You'll find items you can live without under both the Startup and Services tabs. If they prove important, you can always re-enable them. For more in-depth information and control over how services start (automatically or when required), run services.msc, again using the find function. Uninstalling unused applications is also a boon.

How to boost a battery's lifespan

The tricks to maximize your lithium-ion battery's useful lifespan, i.e., the number of times you can recharge it before it no longer accepts one, are pretty basic. There are three things that will prematurely age a Li-ion battery: Consistently draining it to the automatic shutdown point, heat, and over-charging/over-voltage charging. That last practice is actually dangerous and can lead to fire or even explosions.

The number of recharge cycles you'll get out of your Li-ion battery drops with how far you drain it on a regular basis. You can get as many as 5,000 cycles if you only discharge it to the 90 percent level each time, and perhaps only a few hundred if you run it down to 10 percent. Don't go crazy trying to stay tethered all the time. But you might want to break the habit of waiting for the low battery warning before plugging in.

Habitually leaving your Li-ion powered device in a hot car or near another heat source can significantly reduce its recoverable capacity (the amount of charge it can absorb). You could easily reduce a four-hour run time to three hours in a couple of months doing this. Touch chargers, which are only about 80 percent as efficient as wires, turn the other 20 your into heat. Stylish and convenient as they might be, using a touch charger could reduce your battery's lifespan.

Avoiding heat doesn't mean that freezing your devices or batteries will make them last forever. As a matter of fact, Li-ion batteries will not accept a charge if the ambient temperature is below freezing. Hybrid and electric cars that use Li-ion batteries keep them warm in cold climates. Basically, your battery is most comfortable at what you probably think of as just a little cooler than comfortable--60 degree Fahrenheit.

As to the over-charging/over-voltage charging issues, you're pretty much at the mercy of the device, charger, and battery manufacturer. Li-ion batteries have charge controllers that mostly prevent bad things such as overcharging and over-discharging from occurring. But mistakes happen, so if you notice an undo amount of heat in either a charger or the device being charged, stop using it until you find out what's going. Check with the vendor. If it burst into flames, quickly move it to an area where it catch anything else on fire, if you can do so safely, and get away from it. The byproducts of the combustion can be corrosive and toxic.

When you store a lithium-Ion battery, try to store it at 60 degrees with somewhere around a 40 percent charge. The charge will prevent the battery from going to sleep and never waking up. This is why you quite often get a new mobile device that's already partially, but not fully charged.

The Bottom Line

It all boils down to this: To extend run time, turn stuff down or off. To extend a Li-ion battery's lifespan, don't consistently drain it to low levels or expose it to heat on a regular basis. Store it at 60 degrees at a 40 percent charge. Batteries are all about freedom, so try to nurture good habits without killing the joy.

May your batteries run long and linger (and be recycled properly).

This story, "How to live large on every battery charge" was originally published by PCWorld.

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