We've said it once, and we're gonna say it again: battery life is the only stat that matters any more. Sadly, it's also one of the hardest to nail down in a decent, objective manner. Nonetheless, we corralled together a Russian oligarch's wishlist of handsets, and put them to the test.
Like buses, battery tests should always come in threes. Rather than doing just one which only taxes the power-hungriness of a few components, we ran a couple of different tests that, added together, should give a fair representation of battery use.
On the torture rack, we had a bevy of the best modern smartphones. (We've given phablets a miss this time round.) Representing Apple was, of course, the iPhone 5; Windows Phone's corner was defended by the Nokia Lumia 920 and its not-quite-replacement, the Lumia 925; BlackBerry's Z10 weighed in for BB10, and the Android crown was a six-way tussle between the HTC One, Sony Xperia Z, LG Nexus 4, Samsung Galaxy S3, Galaxy S4, and the Motorola Razr HD, which is renowned for slightly-longer-than-average battery life.
This time around, we also rooted and flashed a custom ROM (the release candidate of CyanogenMod 10.1, in case you're wondering). Some custom ROMs claim to have better battery life, a brag that seems to be borne out by our real-world testing; it's interesting to see the difference it's made here, though.
First up was the industry-standard looping of Nyan Cat until battery death. For all our tests, we set the screens on all the devices to a fixed brightness output using a lightmeter (a more objective test than just setting to 65 per cent brightness), loaded up a video over Wi-Fi, and then let the cat bounce until the phones conked out. Everything else -- any push notifications in particular -- were turned off for the duration of the test, since we don't want a tonne of Nigerian spammers fiddling with the results.
Speaking of results: the Moto Razr cleaned up on the first test, setting the stage for things to come. The HTC One and iPhone 5 both collect honourable mentions, and the Nexus 4 and Xperia Z scrap it out for last place, with almost half the battery life of the Razr HD.
Next, the handsets tackled another smartphone staple -- web browsing. We had the phones cycle through a series of image-heavy websites, with the same conditions of a constant screen brightness and no pesky notifications.
Once again, the Razr HD took first place, though the HTC One managed to claw back second place. Otherwise, the results are fairly similar to the video run-down -- the only notable gain was the Xperia Z, which climbed a couple places to become firmly average.
Our final scrimmage was a standby test, in order to reflect the amount of time your phone spends in your pocket, with the screen off but still merrily working away syncing your emails. To conduct the test, we synced the same dozen email accounts to every handset (including the Giz UK tips line, which is guaranteed to make any push server tremble in fear). There were also Facebook, Twitter and LinkedIn (yeah, so grown-up and professional of us) accounts on all the handsets. Finally, an IM bot spammed messages like a hyperactive teenager on speed.
The Razr HD scores three for three; the real surprise here is the CyanogenMod-ed Nexus 4, which pulls out a helluva lot more battery life than its stock-running brother.
There's a clear winner here -- the Moto Razr HD, which came in top in every one of our tests. The HTC One comes second, having beaten out the iPhone 5 in the browsing and standby tests. The clear loser is stock Nexus 4, which was always in the bottom two; the BlackBerry Z10 and Lumia 920 don't exactly score well either.
The surprise this time around, however, is that the CyanogenMod ROM seems to eke substantially more battery life out of the N4 when it's in standby, something we've always suspected but never scientifically tested.
So, if you're after a phone which lasts you a full day, you're most likely heading down the Android or iOS route. Given the HTC One's also a pretty damn fine handset to actually, y'know, use, it would be the logical Android pick, although the Galaxy S4 isn't exactly trailing far behind. For iOS, well, there isn't much choice, but at least you can rest assured the iPhone's up there in terms of battery life.
This article was originally published on the 4th April, but has been updated to reflect the magma-like fluidity of the smartphone market.
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