Battery Life

While we’ve gotten a good handle on how battery life is on the Snapdragon 801 platform with 1080p displays, we haven’t quite seen the same when it comes to a 1440p display. I’m sure that most people already understand the importance of battery life, so I’ll simply reiterate that our testing conditions are standardized. Everything other than the task at hand is turned off to the best of our abilities, and the display is calibrated as close as possible to 200 nits. The device is then run on an endless loop until it shuts down, starting with a fully charged battery. First, we’ll start with the WiFi web test.

I have to stop proceeding with the analysis with a disclaimer though. With the LG G3, we’ve found evidence of dimming behavior with manual brightness. In the worldwide model that we received, the dimming happens soon after setting the brightness level. A dangerous practice for sure if you only measure display brightness once before conducting battery life tests. However, in the SKT and likely the other Korean units that reviewers received, this dimming process takes around an hour or longer (but with a far shallower drop in actual brightness). It's clear that TI's LM3697 is the chip that controls the backlight brightness, but it's unclear what is setting the brightness curve. LG states that this mechanism is part of their 3A system to reduce display power, and they state that the brightness dimming effect is done in an effort to save power by reducing brightness at a rate that would be unnoticed according to the Weber-Fechener law of perception. This does make sense, but LG should offer the option to disable this functionality one way or another.

Web Browsing Battery Life (WiFi)

Here, the LG G3 has a major regression in battery life. While the LG G2 had around 11 hours of battery life on WiFi and was competitive with the Galaxy S5 and One (M8), the G3 is around the iPhone 5s in this test. There are a few reasons for this. If we compare battery capacity vs. display size, the LG begins at a disadvantage to HTC's One (M8). In order to equalize this gap, LG would need to fit the G3 with a 3150 mAh battery, something that would be difficult as a result of the loss in volumetric efficiency from the removable battery. The other reason is due to the lower panel efficiency, which is a direct result of the higher pixel density.

Web Browsing Battery Life (4G LTE)

Surprisingly, in the LTE test we see a significant improvement over the LG G2, although it’s still behind the One (M8) and Galaxy S5 for the same reasons that I discussed in the WiFi test. These gains were likely made by improvements to RF and general process improvements such as envelope tracking and lower power process on the modem and other aspects of the SoC from S800 to S801.

Web Browsing Battery Life (2G/3G)

In WCDMA, there are very few surprises. As a result of bottlenecking on the network connection, battery life drops noticeably. The delta between the One (M8) and the G3 is relatively constant in this test as well, around 15-20% less in general.

Overall, the web test shows the power cost of the 1440p panel. However, in many situations the importance of display power efficiency can drop dramatically, especially if other components consume similar levels of power. To take a closer look at this, we turn to the compute-bound battery life tests. The first is GFXBench, which runs an endless loop of T-Rex on the display until the phone shuts down.

GFXBench 3.0 Battery Life

GFXBench 3.0 Battery Performance

Here, we see that the LG G3 is between the One (M8) and Galaxy S5 in overall runtime. What’s surprising is that end of run FPS is below both the One (M8) and Galaxy S5, even when compensating for the difference in resolution by multiplying the score by 1.77. This actually places the LG G3 behind the G2.

However, looking at the overall picture, it’s very clear that LG is simply using a throttling mechanism that results in sinusoidal behavior. By averaging the last runs, the realistic end of run FPS is around 13.636. By scaling this to the 1080p-equivalent FPS, we see that the end of run FPS is actually around 24.1357. This means that there’s still a noticeable difference between the One (M8) and LG G3 in overall thermal dissipation capabilities, although not nearly as bad as the end of run FPS value might suggest.

BaseMark OS II Battery Life

The next test is Basemark OS II, and we see that the battery life score sits between both the Galaxy S5 and One (M8), although it does worse than both of them in the battery score taking into account performance. 

BaseMark OS II Battery Score

Overall, the LG G3 does acceptably well in battery life. However, after taking into account the dimming function it’s rather concerning how the G3 fails to keep up with the rest of the competition in this critical area. To really get a good idea what why this is though, we have to look at actual power numbers. This will allow us to truly quantify the power differences.

Charge Time

Charge Time

In this test, the LG G3 trails behind both the One (M8) and Galaxy S5 in charge time, although it's quite close to the One (M8). This is strange, especially because the LG G2 has the same battery size. However, this can be explained by the change to charging protocol, as it seems that the G3 doesn't support Qualcomm's Quick Charge technology. Instead, signalling is done over BC 1.2. As we'll see later in the article, this is due to the charger chip used.

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  • peterfares - Friday, July 4, 2014 - link

    I agree. Give me a damn removable battery and SD slot.
    Stacking it might get it to have slightly more capacity but not that much. Like 5% more. I'd rather have it be removable.
  • Krysto - Friday, July 4, 2014 - link

    Android OEMs short-sighted focus on marketing gimmicks to the detriment of actual performance is infuriating. As you said, LG could've chosen a higher quality 1080p display, that along with the same battery would've also given better battery life and higher performance. But no, instead they chose to chase the "bigger is always better" gimmick.

    We have a Full HD display in the palm of our hands - what more could we possibly need? They could've chose a 1080p display with a bigger focus on sunlight visibility, or just leave it the same, and focus on improving the camera even more, or making a more solid device.
  • ZeDestructor - Friday, July 4, 2014 - link

    What kills it for me is the 5.5" Size. As someone who did the Xperia Z->Z1->Z2 route (the LCD did improve successively every generation, especially wrt colour gamut), phones are getting more and more unwieldy. If it weren't for the fact that the Z2 is physically narrower than the Z1, I'd have skipped it and waited for the Z2 or Z3 compact.
  • SleepyFE - Friday, July 4, 2014 - link

    I still prefer battery life. 480x800 is enough for me. It doesn't distort smaller letters, so i can still read a fully zoomed out web page (if it's not too wide). And you can have a smaller phone (a must since i keep it in my front pocket). I also prefer a bit more space between the screen and the edge. Right now i can't use my phone with one hand as it detects the tips of my fingers when i hold my phone. My grip has to be too lose for my liking.
  • ZeDestructor - Friday, July 4, 2014 - link

    480x800 and even 1280x720/1280x800 suck compared to 1080p. It's not just the ability to render, it's the font smoothing that's required. You need extensive smoothing at lower densities, and while it produces something readable (if fatiguing) for Latin-based, Cryllic and most Middle-Eastern and Indial peninsula characters, far-eastern scripts like Japanese or Mandarin render poorly, especially beneath 300ppi.

    Here's a comparison between 300ppi and 600ppi by JDI in 2012:
  • SleepyFE - Friday, July 4, 2014 - link

    Yeah with 3mm blown up to 2cm. But that's not how zoom work is it? Like you said, the font smoothing solves it and since there is less pixels the GPU consumes less power as well.
  • ZeDestructor - Friday, July 4, 2014 - link

    If you've never read Asian characters for any extended period of time, you'll think that font smoothing is enough. Fact is, it's not. With font smoothing, at small sizes, Far-Eastern characters just look like a blurry, gray mess, so people use hand-designed, pixel-perfect bitmap fonts instead.. For an equivalent comparison zoom it out to around 40-50% (because yay 100ppi on most computers :/). The difference in quality matters in person. Not for us, but for other people elsewhere on the planet.
  • SleepyFE - Friday, July 4, 2014 - link

    Another problem with the comparison is the size of Asian characters. In the picture they are the same size as latin characters. They write them bigger on paper for a reason. They would be a blob of ink if they were only a few millimeters. They need to use bigger fonts for their characters. Problem solved.
  • ZeDestructor - Saturday, July 5, 2014 - link

    On electronic media, Asian characters are sized similarly to Latin characters.
  • fokka - Friday, July 4, 2014 - link

    i also prefer battery life, but i think the z1 compact, moto g and moto x are at the sweet spot of resolution for me 720p is nothing over the top anymore and makes for perfectly fine ppi at 4.3-4.7 inches.

    1080p is great too at 5 inches and upwards, but that's already where diminishing returns kick in heavily.

    but 1440p is just stupid with phones you can burn through in 3 hours, if you really want to.

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