Battery Life and Charging

Battery life is one of those things that consistently ranks among the highest in consideration for a mobile device. At the same time, OEMs still seem largely unwilling to double or triple battery capacities between generations, or go the Motorola route and offer two different models with double capacity. The story of smartphones is again this continual competition between everything and the industrial design.

With the One, HTC has gone again to its pyramidal stack of display, then battery, then PCB. The result is the familiar curved backside from where the PCB sits, and a large, thin battery sandwiched between the display and PCB.

The HTC One moves to a 2300 mAh, 3.8V (the higher nominal chemistry that everyone has moved to) lithium-ion polymer battery, giving it a capacity of 8.74 watt-hours. It’s obviously internal and not easily user-replaceable. Of course, battery size doesn’t entirely dictate battery life, it’s just a larger electron tank to draw from. What ultimately is a more interesting is how efficient the platform is which draws from it.

The thing about HTC and battery life specifically is that as of late they’ve been penalizing themselves on the display side of things, which is the single largest consumer of power in a device. A number of other OEMs artificially clamp display brightness just to set a better higher bound for battery life, and for example HTC’s display auto brightness function doesn’t have as much dynamic range as the slider being actuated manually. The result is a phone that’s brighter than it needs to be a lot of the time. On the software side HTC does have system optimizations that do things like batch up network traffic so that the phone isn’t going into a constant cellular connected state and burning power for an app written by a developer who doesn’t know anything about cellular connection state tables, and strategies like suspending the cellular data connection when on WiFi or when the phone is in standby for long periods.

To find out where the HTC One sits in the battery life spectrum, we turn to the newest version of our battery life test. This is now our sixth revision of the battery life test, and we feel is the optimal balance between challenging workloads and idle time. The basic overview is the same as the previous test — we load webpages at a fixed interval until the handset dies, with display set at exactly 200 nits as always. Power saving features (in this case the HTC Power Saver) are disabled if they turn on automatically, and background account sync is disabled. The test is performed over both cellular data on all available air interfaces and over WiFi in an environment with good signal levels. The new test has decreased pause time between web page loads and added a number of JavaScript-heavy pages. I sat down with some UMTS RRC (Radio Resource Control) emulator tools and also made sure we had a good balance of all the RRC states (DCH, PCH if possible, FACH, IDLE) so we weren’t heavily biased towards one mode or the other.

I’ve included the HTC DNA in the fray as well since I’ve had those numbers for a while. Let’s start with the WiFi test, where we attach the device to a dedicated WiFi network with no other clients.

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

The One includes the newest BCM4335 WiFi/BT/FM combo from Broadcom, which is still built on a 40nm process. For the purpose of the battery life test I attached the One to the same AP as I’ve always used, however I will repeat with my 802.11ac AP in due time to see whether the shorter duty cycle afforded by a much higher PHY rate makes any difference.

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

On cellular data the One isn’t bad at all, looking at the 3G result from final hardware and final software. I consider this pretty good all things considered for the HTC One, and mirrors my experience.

Cellular Talk Time

On cellular talk time the One really shines, coming in well ahead of almost everything else. This is an impressive result.

WiFi Hotspot Battery Life Time

As a hotspot once again we have great battery performance. This test consists of four of the page loading tabs running on an attached notebook in addition to 128kbps streaming MP3 audio being played on the device. This is a challenging test that results in the cellular connection being lit up almost constantly, and isolates out display.

My subjective impressions using the HTC One as my personal device are that battery life is quite good, and moreover that the DNA battery life also was better than some other phones people had no problems with in 2012. I have yet to have an issue making it through an entire day on the HTC One, even when aggressively using the camera. If I knew I was going to be away from the charger for a long time, I did enable the power saver, which sets max CPU clock on the Snapdragon 600 to around 1.3 GHz in addition to lowering brightness a little bit, and a few other things as shown in the previous screenshot. In practice I really don’t notice much of a performance difference with the power saver box checked unless I’m really looking for it, but this probably dumps the SoC into a better voltage state to say nothing of how much lower active power is.

Charging on the HTC One takes a little while longer than I’m used to for other devices. I get lots of requests to do charging tests and have been running them on everything I can lately, but anything power related remains an involved process. To test the best case charge time, I have a dedicated power supply voltage limited to 5V and capable of supplying a lot of current. I emulate the USB BC1.2 charging spec on a breadboard and connect USB to the device, then time how long it takes to charge devices completely. I plug the phone in after it dies running our battery life test, and time the amount of time from that fully dead, won’t-turn-on state to fully charged, either with a green LED or when charge current goes to zero for devices without a charge status LED.

Device Charge Time - 0 to 100 Percent

The HTC One definitely takes a while to charge. What’s interesting however is that the charge curve gets the One to 85–90 percent under the normal 3 or so hours, it’s that last ten percent that takes forever. I also have confirmed that Qualcomm’s Quick Charge is not being used on the HTC One, for whatever reason, possibly to maximize compatibility with the portable USB battery chargers that are now proliferating. The PMIC is there, it just isn’t enabled. My guess would be that HTC wants to prioritize battery longevity and minimize any even potential extra wear since the battery on the One is sealed inside.

Hardware (Continued) and Cases HTC's Ultrapixels - Bucking The Trend
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  • danbob999 - Monday, April 08, 2013 - link

    The Samsung is smaller despite a larger display. A 4.7" phone is not more comfortable if it is larger than a 5" one.
    Even if you don't care about the removable battery, it is larger in the SGS4 so it will last longer.
    Also while I understand that some people prefer the look of metal, plastic is more practical as it is lighter and absorbs shock better. So plastic is better build quality.
    And I will wait for reviews about the SGS4 before telling which one has the best camera.
    Reply
  • blacks329 - Monday, April 08, 2013 - link

    So you won't wait for the reviews and eventual drop tests to see which is better between the two for battery and build quality?

    Also larger battery does not always mean last longer (as is also mentioned in the review; it comes down to software optimization, hence why the iPhone generally does better with considerably smaller batteries). Especially with a higher clocked SoC it might not be 'better,' as you've expected.

    I'd be surprised if the SGS4 garners any sort of Anandtech Editors Choice award. While HTC is actually making functional improvements in terms of how they think hardware and software for a phone Samsung just throws horsepower. I hope the One sells well enough for HTC, b/c this is the phone all other manufacturers should be striving for.
    Reply
  • augustofretes - Tuesday, April 09, 2013 - link

    Of course it's more comfortable, especially because the biggest issue with phones is not the size in every dimensions, the problem is width, and the S4 is wider than the HTC ONE.

    "it is larger in the SGS4 so it will last longer" Is just false. Especially considering how inefficient AMOLED is while displaying whites.

    "And I will wait for reviews about the SGS4 before telling which one has the best camera." I don't need to. The S4 will take better pictures when there's plenty of light, and it will be abysmal when there's no light.
    Reply
  • darwinosx - Tuesday, April 30, 2013 - link

    Turns out the larger battery in the S 4 doesn't last longer. Also if you had read the review you are commenting on you would have seen Brian say the same thing. Reply
  • superflex - Friday, April 12, 2013 - link

    Samsung users need a removable battery because they need to force reboots of the crappy Touch Wiz UI. Reply
  • darwinosx - Sunday, April 07, 2013 - link

    Newsflash..not everyone uses a case or wants one. Its a pretty pitiful comment that cheap plasticky phones don't matter because you can slap a plastic case over the existing plastic. Smells like rationalization. Reply
  • darwinosx - Tuesday, April 30, 2013 - link

    Not everyone uses cases and who has inferior hardware. Reply
  • nyrulez - Saturday, April 06, 2013 - link

    I am surprised why folks don't care about SD card expansion at all. For big media consumers, that can be huge. I was constantly hitting the wall on my 16 GB iPhone. It was extremely annoying and not much I could do about except delete my music ir apps. After moving to a Motorala Razr + 64GB micro SD card, it hasn't been the same since.

    Though this one is super awesome and would love to get it, the horror of running out of space all the time stops me. Thoughts ?
    Reply
  • tainguyen81 - Saturday, April 06, 2013 - link

    you do know this phone come with 32 and 64GB right? then you can buy a USB-OTG cable and connect any 64GB or 128GB usb stick to it as you like. This is better because you don't have to take the back cover in/out constantly.

    In my opinion, 64GB internal on the HTC one is way faster performance compare to 16GB s4 with 64GB sd card everyday.
    Reply
  • therealjoshhamilton - Saturday, April 06, 2013 - link

    It's not just your opinion, r/w on internal was 19/14mbs on the galaxy s, class 10 sd cards are stuck at 10mbs (and that's if you shell out the money for class 10). Reply

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