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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  • dishayu - Wednesday, November 14, 2012 - link

    Meh, that is how they statistically show you that thermal throttling is affecting the performance. Your accusation would have help good if they had only published the freezer benchmarks. But they published both because they wanted to showcase that the phone thermally throttles itself (i.e. a negative point about the phone)... How exactly is that partial? Reply
  • kgh00007 - Monday, November 19, 2012 - link

    I think it is particularly significant that this phone was selected to be the first phone that was actually put in a freezer and the results published, why not the iPhone or some other phone that was known to be trottling?
    Seriously, think about it.
    There is a big difference between stating that a phone throttles and the theoretical performance is X and actually putting a phone in the freezer and publishing the resulting benchmarks.
    I am entitled to my opinion, and my opinion here is that somebody is working for the man, the wrong man.
    Reply
  • kgh00007 - Monday, November 19, 2012 - link

    There is quite a big difference between stating that a phone is throttling and the theoretical performance should be X, and putting a phone in the freezer and publishing the resulting benchmarks.
    The choice of phone to be the first to recieve this treatment is suspicious to me.
    My opinion, which I am entitled to, is that somebody is working for the man, the wrong man.
    This is evident to me, think about it yourself.
    Reply
  • thesavvymage - Wednesday, November 14, 2012 - link

    they basically said "the phone IS being thermally throttled. here's what would happen if it wasnt..."

    nowhere does it ever say that the freezer tests would ever be indicative of a real world test. they are just showing for information
    Reply
  • kgh00007 - Monday, November 19, 2012 - link

    People are aready taklking in the comments about how this phone has to be put in the freezer in order to gain maximum performance from it.
    People are not saying the same about the iPhone, that is the significance.
    As I said something fishy going on here and I don't like it.
    In fact this is the first time Anandtech has dissapointed me with a review, but it is a rather large dissapointment.
    Reply
  • galtma - Wednesday, November 14, 2012 - link

    Is it feasible to replace the RAM in the N4 to upgrade it to 32gb? Where in the internals would you dig? Reply
  • noblemo - Wednesday, November 14, 2012 - link

    I think you are referring to the NAND Flash, but in either case the NAND and RAM are soldered to the mainboard. Brian made the following comment in the section, "Inside the Nexus 4" (page 7 of the review) regarding the NAND:

    "I couldn’t get the can off of what appears to be the eMMC (the only remaining large package), we’ll have to see if anyone else wants to do some destructive digging to get that one."

    He is referring to the device under the EMI shield (with a QR code label) in the lower left corner of this image:

    http://images.anandtech.com/galleries/2435/Nexus-4...
    Reply
  • praveen44 - Wednesday, November 14, 2012 - link

    Excellent review. Reply
  • spiritrajat - Wednesday, November 14, 2012 - link

    most exhaustive review..being an electronics engg myself i realy enjoyed going through the reveiw...job very well done Reply
  • noblemo - Wednesday, November 14, 2012 - link

    Q: Hey, Nexus 4, why so blue?
    A: Because no one at Google is responsible for display calibration.

    It's unfortunate that color accuracy does not get more attention from manufacturers.

    Was throttling observed and was there a noticeable impact during daily usage? Any thoughts on whether it would be an issue in climates with ambient temperatures greater than 30C?
    Reply

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