Battery life remains the achilles heel of Android. In spite of the improvements we’ve witnessed over the last year or two, which have seen both the operating system and the firmware installed on devices even more optimised, the increasing power demands of the latest hardware tends to cancel out any improvements. As a result we’re still left with nightly charges to keep our devices ticking over.
There are lots of things you can do to improve the performance of your phone’s battery, including adjusting the screen brightness, preventing too many apps from syncing too often, and turning off power-sapping features when you’re not using them. But only if you turn to hacking will you be able to make potentially considerable gains.
‘Undervolting’ isn’t for the faint hearted. If the thought of merely rooting your phone brings you out in a cold sweat then move on now. The process required involved flashing an undervolted kernel to your phone. This, as its name suggests, literally reduces the voltage that the phone uses, and that reduced voltage should offer significant battery savings. The idea is that the default voltage setting is set by the hardware manufacturers to be on the high side to ensure reliable performance, and that it can therefore be safely reduced to a lower level on a device-by-device basis. You can do this by first flashing a new kernal – the part of a system that manages the communications between the hardware and the software – that supports undervolting, then installing an app to adjust your settings. Undervolting is often supported in overclocking apps such as SetCPU and Voltage Control.
The danger is that reducing the amount of power that parts of your phone’s hardware use that can have a serious knock-on effect in its performance. If you go too far you could leave the phone unstable and barely usable; and even more modest reductions are liable to make the handset feel slower than it previously did. And if you live in an area of poor network coverage then you may find your problems are exacerbated. The trick is to not push it too far, and accept smaller incremental improvements rather than going as far as you can from step one. And, of course, check out the feedback from the community on the ideal settings to use, especially if electronics is not your forte.
Inevitably, the extent to which undervolting improves your battery life is open to debate. In our tests running an HTC Desire, we did feel like we gained maybe about half a day under certain usage conditions, although others suggest there may be a placebo effect in play. Ideally you should leave your new setup for a couple of days and then re-evaluate, rather than expecting immediate miracles.