Battery life in the Nexus 4 is a big concern for many, especially since the Nexus 4 isn’t designed to have a user replaceable battery. What’s inside is a 2100 mAh 3.8V battery which is 8.0 watt-hours. I had been wondering for a while what the chemical compound used in the 3.8V battery cells we’re seeing emerge was, and finally got a tad more info at least about the LG Chem approach. This is the higher voltage chemistry from LG Chem which is Lithium Cobalt Oxide (LiCoO2) based and includes electrolyte additives to prevent gas generation in the cell which affects lifetime during high temperature periods. Although getting the back off of the Nexus 4 is relatively easy and requires just removing two Torx 4 screws and prying up on the plastic, I doubt anyone is going to make a back to accommodate an extended battery due to the presence of 4 antennas which are integrated into the back cover.

The Nexus 4 incorporates wireless charging into that back alongside NFC. For wireless charging the Nexus 4 uses a TI BQ51051b wireless power Li-Ion charger receiver. I’ve been pretty remiss in looking into wireless charging and actually trying it myself, so I went ahead and bought a two-position Energizer Qi compliant charging mat.

The Nexus 4 is Qi 1.1 wireless charging forum compliant, so any charger that is Qi compliant or includes the logo will charge it. Aligning the Nexus 4 on the Energizer mat is a bit tricky since the surface is slick and angled down, and the back of the Nexus 4 is primarily glass, but it isn’t difficult after you know where to align. The Nexus 4 charges from fully discharged to completely charged in 3.033 hours on the Qi mat, which is basically the same charge time as I saw off of microUSB on a BC 1.2 charger.

 

In Android you’ll see Charging (Wireless) when this mode is employed. I used the Palm Pre touchstone charger a lot back in the day and saw that get pretty hot during a charge cycle. The Nexus 4 doesn’t get nearly as warm. I’ve noticed that at the top of the charge cycle you’ll see the Nexus 4 selectively draw power from the charging dock since there doesn’t seem to be an equivalent trickle charge mode or something, but this is normal.

Battery Life

I’ve had the chance to run more battery life tests on the Nexus 4, and run the cellular test a few more times. The results are quite consistent and we don’t see that result change very much at all. I’ve also added the call time test and tethering results.

We regularly load web pages at a fixed interval until the battery dies (all displays are calibrated to 200 nits as always). The differences between this test and our previous ones boil down to the amount of network activity and CPU load.

On the network side, we’ve done a lot more to prevent aggressive browser caching of our web pages. Some caching is important otherwise you end up with a baseband test, but it’s clear what we had previously wasn’t working. I’ve made sure that despite the increased network load, the baseband still has the opportunity to enter its idle state during the course of the benchmark, we’re not destroying the RRC states with too aggressive of a load time.

We also increased CPU workload along two vectors: we decreased pause time between web page loads and we shifted to full desktop web pages, some of which are very JS heavy. The end result is a CPU usage profile that mimics constant, heavy usage beyond just web browsing. Everything you do on your smartphone ends up causing CPU usage peaks - opening applications, navigating around the OS and of course using apps themselves. Our 5th generation web browsing battery life test should map well to more types of smartphone usage, not just idle content consumption of data from web pages.

As always we test across multiple air interfaces (3G, 4G LTE, WiFi), but due to the increased network load we actually find that on a given process technology we see an increase in battery life on faster network connections. The why is quite simple to understand: the faster a page is able to fully render, the quicker all components can drive down to their idle power states. All Android tests use Chrome and 5GHz WiFi unless otherwise listed.

The tethering test still consists of four tabs of the webpage tests in conjunction with a 128 kbps streaming MP3 radio station over the smartphone’s personal WiFi hotspot.

AT Smartphone Bench 2013: Web Browsing Battery Life (3G/4G LTE)

AT Smartphone Bench 2013: Web Browsing Battery Life (WiFi)

Cellular Talk Time

WiFi Hotspot Battery Life (3G)

I've run and re-run the battery life tests on the Nexus 4 and they haven't changed since our preview a whole bunch. The result is battery life that isn't really chart topping, yet in my time with the Nexus 4 I haven't really been want for more battery life at any point. I'm able to get through a single day with the device set on auto brightness. 

Introduction and Hardware Performance Revisited
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  • zeroidea - Wednesday, November 14, 2012 - link

    It's Tucson, AZ!

    They must have been taken a few weeks ago (a lot of the streetcar construction downtown has been completed)
    Reply
  • DukeN - Tuesday, November 13, 2012 - link

    Brian, are you able to verify if the material is actually rubber? This would be a serious issue for many users, including some in my family with severe latex allergies. Reply
  • PeteH - Tuesday, November 13, 2012 - link

    Wow, that didn't even occur to me, but it could be a real problem. It's not like latex is an uncommon allergy either, so hopefully Google or LG thought about that and used something other than rubber. Reply
  • Rits - Tuesday, November 13, 2012 - link

    Its rubberised plastic. Shouldn't be a problem at all to latex-allergic folks. Reply
  • PeteH - Tuesday, November 13, 2012 - link

    Not doubting you, but do you have a source? Reply
  • Rits - Tuesday, November 13, 2012 - link

    Previous LG devices that had the same material were latex-free. There is no reason this one would deviate. But, you could always email LG/Google for an official confirmation. Reply
  • MadMan007 - Tuesday, November 13, 2012 - link

    Should have used a dual core CPU with a decent GPU. Quad core is a waste in phones because overall it hurts battery life more than it helps certain usage models, and if there's so much throttling what's the point.

    Does Android do thread parking? Do these CPUs have per-core power gating?
    Reply
  • JohnnyL53 - Tuesday, November 13, 2012 - link

    Throttling may not be an issue in the real world in terms of a noticeable affect and may just show up in benchmarks. In other words, who cares what the benchmark performance is if its at such a high level it's not perceptible? What I never see explained is how far apart do you need to get before you can distinguish one device's performance from another. Granted on most of the tests the iPhone far outpaces any other phone, but is it even noticeable? Are we just talking bragging rights, future proofing, etc? Reply
  • name99 - Tuesday, November 13, 2012 - link

    The value of a faster CPU on a phone, for normal people, right now, is that the phone feels snappier. So, for example, an iPhone5 feels perceptibly faster than an iPhone 4S not because computational tasks take 1 minute instead of 2 minutes, but because a dozen small things take .1 second instead of .2 seconds.

    From this point of view
    (a) thermal throttling is no big deal, and I personally have no problem with it. It was a good idea when Intel started it years ago (to the accompaniment of a massive chorus of whining) and it would be a fine idea to have it as built into an ever wider selection of phone chips.

    (b) quad-core remains a solution in search of a problem. Maybe one day it will have value; maybe it has value for games (which I don't care about). But for the way I and my crowd use phones, it has no value yet.

    (c) the present collection of benchmarks are largely useless because they do NOT track this essence of snappiness which is what most people mean when they say a phone is "fast". Yes, if you're a developer writing demanding code you care about very particular aspects of the phone --- perhaps you care about the memory bandwidth, or the FLOPs, or the random flash write performance. But for most people, what matters is the snappiness. Existing benchmarks are a poor proxy for that feeling, and I do wish the serious blogs could do better.

    Right now all we have is this lame sniping like 12 yr olds: "My Nokia feels fast", "Oh yeah, well my Samsung feels even faster", "Well my iPhone feels fastest of all". And regardless of your feelings about Apple, if you support Team Android or Team Windows, you should be pushing for snappiness benchmarks because that is one of Apple's great strengths --- they don't care about, and don't optimize for benchmark numbers, they optimize for snappiness, and buyers do appear to be aware of and notice this. As long as the non-Apple market is forced to compete on these "overt" benchmarks as ways for each vendor to differentiate themselves and show their technical superiority, what will be optimized for are benchmark numbers, NOT user feel and snappiness.
    Reply
  • Zink - Tuesday, November 13, 2012 - link

    I think with a DSLR at 60 FPS and editing to synchronize individually recorded videos it would be possible to do accurate side by side comparison of app responsiveness and web page loads. With a bit of video analysis, graphs could be made comparing performance down to the frame and FPS in animations measured.

    You could even do this on the go for a real world performance comparison. A normal day of use could be simulated by walking/commuting around your city and setting up a tripod in an apartment, on the sidewalk, inside an office building, at the bar etc. Then run several tests on each phone where you get the phone out of your pocket like normal and open a web page, post a comment, take a photo etc. all while the screen is on camera. Several similar tasks could be averaged into a single category score for a bit better repeatability.

    With proper analysis of the resulting video a pretty damn accurate comparison of the whole cellular, hardware and software system could be made. Basically the ultimate benchmark measuring user phone performance. I've seen some well done side by side comparisons but never in depth or with good numbers along with the video.
    Reply

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