How to save your phone's battery

Today's smartphones have a multiplicity of applications and functions running in the background, many of them unnoticed by the user.

That is, until they drain the phone's battery dry. At first, it's not so easy to tell why one's new top-level smartphone gives up the ghost after only two hours. But the fact of the matter is that, being online all the time has its price and some modern applications really do eat up battery time.

But, it doesn't take much to let the good times roll again. A few simple tricks can turn a smartphone back into a marathon runner. Indeed, there are a few apps out there to help extend a phone's life.

Screen illumination, satellite navigation systems like GPS (satnav) and data transfers via UMTS are among the most energy- intensive functions out there, says mobile expert and freelance author Daniel Lueders.

Thus, one easy way to conserve battery life is to change screen illumination settings to the lowest level, something done simply enough with most phones.

But that leaves accessing websites via UMTS and navigation programmes like Google Maps to eat up your battery life. One tip is to make sure that navigation software is turned off as soon as a destination's coordinates are found. Otherwise, the mapping software can continue to run in the background, leaving a smartphone drained after two hours, says Lueders.

If you're willing to only use a phone for calls, even if only for a short time, then deactivate your UMTS function. The same goes for wireless functions. "Otherwise the gadget is permanently looking for accessible networks," says Lutz Labs, an editor at German technology magazine c't.

Many smartphones that use the Android operating system include a page on their settings menu that shows which applications use the most energy. When underway, a good idea is just to switch to airplane mode, which turns off the satnav system, says Lueders. That's especially true when travelling on a stretch with a lot of tunnels, since the smartphone will burn up a lot of energy looking for a provider.

"You can quickly double or triple your battery life with these kinds of steps." Labs demonstrated how radically a smartphone's power consumption can vary. In airplane mode, a Motorola Milestone used 6.4 milliwatts. But, when uploading data via UMTS and taking a video, power consumption shot up to 3 watts - meaning power usage went up by a factor of 500.

Even a five-minute activation of the display can cut standby time in airplane mode by up to six hours. It also happens that smartphones sometimes give up the ghost after only a few hours when taken abroad. Most of the time, this is because the smartphone is looking for its usual provider in vain, says Lueders.

That problem is solved by turning off the automatic search function and setting up a connection manually. Another idea is to turn off the automatic downloading of emails and manually direct the smartphone to download them, also saving energy.

There is also a host of new, smaller apps designed to help save energy. The free app Juice Defender provides Android phones with automatic settings designed to extend battery life, says Labs. The software determines if one is home or in the office and then activates functions based upon one's location, turning off unneeded ones.