Make your battery last longer without dumbing down your smartphone

Phones get better all the time. Innovation goes real quick, except for one thing: your 22nd century smartphone is powered by a 19th century battery.

You can plug your phone into a wall or USB port whenever you get a chance, but you'll need to have a power source and cable around for that, which defeats the purpose of a mobile pocket-sized device. That's why you need to tell your phone to go easy on your battery.

There are plenty of sites that tell how to increase the battery life of your phone. Most of these sites repeat the same story: switch off everything that makes your smartphone smart and your battery will last all weekend.

But what if you want to stretch your battery without dumbing down your phone too much?

Root and undervolt

Rooting your phone doesn't make any difference to your battery, but it opens up ways to make your phone less hungry for power. A rooted phone can be undervolted, which can increase battery life by hours without any performance loss. SetVSel is an example of an app that can undervolt (and under- or overclock) your phone. There are many similar apps, so there's always one that works for you.

Control your radios with a power widget

Keeping your GPS, data and WiFi radios running all the time is like leaving the lights on when you go out or brushing your teeth with the tap running.

GPS sucks your battery dry quicker than anything else. In theory you can keep it running, because it's only active if an app needs it. In real life there are plenty of apps that abuse your GPS position for no other reason than to spy on you or download ads targeted at your location. Switch GPS off when you don't need it. Network location eats less power, but if you use lots of apps that request network location for no good reason your battery will pay for it.

Mobile data consumes lots of battery power when used, so use WiFi if available. However, an idle WiFi connection uses more battery power than an idle mobile data connection, especially when you're on the move and your phone keeps jumping from one router to the next. If you keep a standby connection to keep Viber or Whatsapp online use this rule of the thumb: WiFi when indoors, mobile data when on the move.

If you live in a place full of free WiFi or if you're roaming abroad and you're not gonna use the overpriced international 3G or 4G connections, switch your phone to 2G mode. It doesn't matter for WiFi. It doesn't make a difference for voice calls either. But switching to 2G-only makes your battery last a lot longer.

In a meeting, classroom, at a concert? If you're not answering your phone, then why let it shake to inform you about calls and texts that you're gonna ignore anyway? Don't put your phone in vibration mode if you have no intention of using it. Use airplane mode instead. Of course switching your phone off during meetings makes it eat even less power, but rebooting your phone takes a lot longer than switching out of airplane mode. Powering off is not worth the trouble if it's only for an hour or two.

Your bluetooth radio uses very little power. Switch it off if you like, but you won't notice any difference.

The problem with toggling GPS, data, WiFi and 3G/4G on and off is that their switches are buried deep down in the settings menu, so most people just keep everything switched on. If you have to dig into there often your smartphone becomes very dumb indeed. That's why you need quick access to the switches so you can flick 'em with a simple single tap.

Many phones come with built-in power bars, but they're ugly and the mobile data toggle is usually missing. You're better off with a switch app from the Android Market. My favorite widget to toggle my radios really quick is Widgetsoid. This app has a rather steep learning curve, but it's worth it because it has more functions and customisation options than any other app. If you want something simple, use Dazzle. If you don't want to have a switcher widget on your home screen, Quick Settings can put it in your notification bar or under a long-tap of your search button.

Unfortunately there's no quick way to toggle network location. You'll still need to go into the Android settings for that.

Use AdAway, AdFree, DroidWall, and LBE Privacy Guard

Less data means less power (in many different ways). A low power app or efficiently coded website can become a data and battery drainer if it pulls in lots of bloated advertisements. AdFree and AdAway block most banner farms, which results in less data and battery consumption.

DroidWall lets you control which apps can go online. You can keep any app offline completely, or limit them to WiFi only. This is a good way to stop "phone home" behaviour, and also improves the efficiency of apps that go online for the sole purpose of downloading unwelcome ad banners.

LBE Privacy Guard can keep apps offline. In addition, it can stop apps from accessing your location. Your phone has plenty of apps that track your whereabouts for no good reason at your expense. New versions of LBE Privacy Guard have the outbound firewall functions of DroidWall built in.

Don't let your widgets suck your battery dry. There's really no reason why your weather widget should update 30 times a day. Most weather apps punish your battery by using your data connection and your GPS. Your Facebook widget doesn't need to pull in status updates every ten minutes unless you're a hopelessly addicted junkie who needs six Facebook shots per hour. Same goes for other apps that autosync data: does your phone really need to check your mail every fifteen minutes? Do your apps really need to check for their monthly update twice a day or should you let the Android Market handle app updates instead?

Turn off the lights

Your screen eats batteries for breakfast. Head to the settings menu and set the timeout for your screen to the minimum you're comfortable with.

By default your phone display is way too bright, especially at night. Using the auto-brightness setting of your phone helps. Reduce the brightness even more when it's dark outside. It's better for your eyes and better for your battery. Switching the lights from the Android settings is so inefficient that you'll be tempted to leave 'em burning at full force, so use a widget instead. Apps like Widgetsoid, Dazzle, and Quick Settings put the light switches of your phone within easy reach. One tap is enough.

AMOLED screens need less power to show dark pixels than light pixels, so a dark theme and wallpaper help you save battery juice. If your phone has a normal LCD screen the color doesn't make a difference.

Use task killers wisely

In Android, empty memory is wasted memory. Apps that are silently cached in RAM don't drain your battery, and when you relaunch them they start up faster. Task killers that shut down apps, only to shut them down again and again after the system has reloaded them hit your battery in a bad way.

That doesn't mean that you should let everything run in the background. Some apps refuse to sleep and keep pulling data and location info when you're no longer using them. Google Maps is among the more famous offenders. It pays to really shut those apps down after use, and to use a startup manager to make sure they don't autostart when you boot your phone. Just make sure that you shut down the right apps instead of blindly clearing your RAM. Killing apps the right way saves power, killing apps the wrong way wastes power.

Automate

Your phone can switch to a reduced power state when your battery level gets low. Use that feature! Free apps like JuiceDefender can switch off battery drainers on a schedule (for example, at night when you're asleep). The automated schedules are only useful if you have a somewhat regular and predictable lifestyle, but if that's you then use it to your advantage.