Battery Life and Charge Time

The Galaxy S 4 features a removable 9.88Wh battery with 3.8V chemistry. The battery design is par for the course for any high end smartphone, but the fact that it's removable remains a staple of the Galaxy S design. Whether or not the bulk of consumers actually use the flexiblity offered by a removable battery is up for debate, but there's no doubt about the fact that Samsung has a strong following of users who appreciate the feature.

Unfortunately, only having access to the Sprint version of the Galaxy S 4 to review, most of our battery life tests on the cellular network aren't all that useful. The good news is that our WiFi tests should at least give you an idea of how well the SGS4 will compare to the HTC One when both are on the same network. We're using the latest revision of our smartphone battery life test to compare performance of all the key players here. 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 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.

As the most relevant comparison of platforms we have today, we'll start with the WiFi version of our web browsing test:

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

On WiFi the Galaxy S 4 falls behind the HTC One by an appreciable amount, however there's still an improvement in battery life compared to the Galaxy S 3. The Galaxy S 4's battery life isn't bad by any means, but do keep in mind that this is a large phone with a large display and a very powerful SoC. For much of the past year we've been talking about an increase in dynamic range in total platform power of high end smartphones and the Galaxy S 4 is no exception. Run it at full brightness or keep many cores running in their maximum performance states for a considerable period of time and you'll be greeted by a phone that's quickly in need of a power outlet.

As I mentioned earlier, we only have access to the Sprint version of the Galaxy S 4 at this point which unfortunately means that our 3G results aren't all that comparable to other devices here.

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

Even on Sprint, the Galaxy S 4 does surprisingly well.

Cellular Talk Time

Talk time is excellent on the Galaxy S 4, with the phone delivering effectively the same battery life as the HTC One. Without having to power on that huge display, the Galaxy S 4 can last for a very long time on a single charge.

WiFi Hotspot Battery Life Time

A combination of the Sprint network and the fact that the Galaxy S 4's display remains off during our hotspot test resulted in great battery life here as well. Again, this data isn't all that useful if you're not on Sprint but Samsung tells us we should be able to get our hands on an AT&T SGS4 in the not too distant future.

Charge Time

Samsung appears to implement Qualcomm's Quick Charge specification in the Galaxy S 4 and its bundled charger. I realize we haven't done a deep dive into what Quick Charge is and how it works, but I'll try to go through a quick explanation here. Most conventional chargers are linear, they take a fixed amount of input current (at 5V) and pass it along to the device being charged. The problem is that at deeply discharged states, the device's battery might be at a substantially lower voltage. A traditional linear charger won't change the current supplied based on the voltage of the battery being charged, and as a result can deliver sub-optimal charge times. When implemented, Qualcomm's Quick Charge technology can vary output current based on the voltage of the battery being charged, which results in less power being dissipated as heat and more being delivered to charging the battery itself. The table below helps illustrate the savings:

Quick Charge, at least in its currently available 1.0 specification, is still bound by the 5V limits of the USB BC 1.2 specification. The next revision of Quick Charge will enable higher voltage operation for even faster charge times.

Qualcomm Quick Charge 1.0, Theoretical Example
  Input Current @ Voltage Input Power Output Current @ Discharged Battery Voltage Output Power
USB BC 1.2 - Linear Charger 475mA @ 5V 2.375W 475mA @ 3V 1.425W
Qualcomm Quick Charge 1.0 475mA @ 5V 2.375W 700mA @ 3V 2.100W

The non-linear nature of Quick Charge significantly shortens charge time, particularly in the very early stages of charging when the device's battery is presumably fully discharged. As the device's battery voltage increases, current delivery tapers off and the QC advantage is no longer as great as a standard USB BC 1.2 solution. The end result though is significantly improved charge times.

The graph below shows the benefits of using Samsung's own charger vs. a standard charger that implements the USB BC 1.2 specification. When used with the bundled charger, the Galaxy S 4 recharges much faster than HTC's One, despite using a larger battery. Obviously the Galaxy S 4 will charge with any USB charger, but the charge time will simply be longer. Samsung uses a voltage divider and signals the presence of their own charger by sending 1.2-1.3 V across the D+ / D- pins, this is similar to what Apple does with 2.0 or 2.8 V across the pins for various USB chargers they've shipped over the years. This signaling is essentially Samsung's proprietary tablet charging signaling which they've employed on the Galaxy Note 2 and now SGS4, in fact the two use the same exact charger, so it's worth tossing out your old ones and getting the appropriate one to take advantage of the faster charging.

Device Charge Time - 0 to 100 Percent


Introduction & Design Galaxy S 4 - Powered by a Better Snapdragon 600 (APQ8064AB)?


View All Comments

  • RiotSloth - Saturday, April 27, 2013 - link

    Bizarre, had to read that twice to make sure you weren't joking. Have you read the HTC One review? Seriously, you think removable battery and sd card slot is a game breaker? Jokes.... Reply
  • GotThumbs - Wednesday, April 24, 2013 - link

    IMO whether a phone has a plastic or aluminum shell adds absolutely zero to the daily functionality of any phone. If one can make a case for increased signal strength or something other than just that its NOT metal, I'd see that as an acceptable functional difference. It just comes off as unnecessary filler IMO.

    Most users will be wrapping thier phones in what.....whats that....some form of plastic or rubber protectors? For those of you who are very good at caring for your phones and choose not to use any form of additional protection, what are the real world odds that the metal case will be better protection over plastic? Perhaps there should be a rigorous test scenario set up by Anandtech to test the reality of true protection using metal over plastic cases?

    The 2014 Ford Mustang comes with either a 3.7L V6 (305 HP) or a 5.8L supercharged v8 (631 HP) while the core frame and shell are both the same. My point is.....It's what's under the hood that really counts.

    Same with mobile phones today. Please stop focusing on case materials if they have zero to do with operation/specs.
  • GotThumbs - Wednesday, April 24, 2013 - link

    My point using the Mustang...would you prefer the V6 or the v8?

    No factoring cost of fuel of course.

    Best wishes you whatever you select as your mobile phone.
  • Zeratul56 - Wednesday, April 24, 2013 - link

    Your argument is ridiculous. The 2014 mustang is something most people can agree is well designed and beautiful car.

    A better comparison would be would you rather have that supercharged v8 in the body of The current mustang or an old 90's beater.
  • kevith - Thursday, April 25, 2013 - link

    Correction: Most people = Most Americans Reply
  • CoryS - Friday, April 26, 2013 - link

    Correction...some Americans. Reply
  • Crono - Wednesday, April 24, 2013 - link

    Last time I checked, I don't hold my car in my hand. Plus the comparison should between a Mustang and an uglier higher HP car.

    And I do prefer the V6 as a daily driver. You can't just leave fuel cost out of the equation because you want to.

    HTC One and 2012 Mustang V6 owner.
  • Kutark - Wednesday, April 24, 2013 - link

    What you failed to mention in your example is that the base v6 mustang looks almost nothing like the GT500. People would NOT pay the premium for the GT500 if the only difference was the engine/drivetrain. Aesthetics are extremely important to people and not just for outward reasons. The gt500 looks absolutely amazing, the base v6 while it doesnt look bad, is only moderately attractive, but still very "meh". A little goes a long way. Just like why HTC's plastics felt better than Samsungs.

    I am a fan of engineering. Its why i tend to prefer german cars over american cars (though there are some im impressed with, cadillac CTS-V for example). If something has brushed aluminum or magnesium, or billet aluminum, etc etc. I'm all about it. And it has nothing to do with what other people think.

    Also, like someone else said, cost benefits are meaningless unless they are passed on to the consumer, which they typically arent. This phone will likely cost as much as the HTC One and frankly its not a better phone. Its more like comparing oranges to tangerines. Basically IMO if you dont care about a replaceable battery or an SD slot, get the HTC One, if those two features are important to you, get the samsung. Im sure people would be pleased with either phone.
  • beluga - Wednesday, April 24, 2013 - link

    I am fine with the choice of materials. The GS3 looks fine to me. I don't treat my phone like a precious jewel but take it into rough conditions. Plastic is softer than metal so when it drops it acts as more of a bumper for the fragile parts inside. If it gets scratched up I get another back off ebay for a few bucks. And most importantly - it makes the back easily removable to access battery and storage without using tools. Reply
  • Roffles12 - Wednesday, April 24, 2013 - link

    fans of the solid aluminum chasis are a very vocal and illogical minority. very annoying in fact. i have yet to hear any logical argument for why it's better. "it feels nicer in the hand" isn't a reason, but rather a completely subjective opinion. by my logical observation, the aluminum phones are actually more fragile and prone to scratching. aluminum is also more rigid which means it will have greater energy transfer on shock impact, resulting in a greater chance of shock energy transferring to the screen, thus damaging it. you're almost forced to purchase a case to protect it.

    i think the sales figures for the gs3 alone show that most people don't care if their phone looks like a piece of jewelery. please save your opinions of vanity for the imaginary fashion show in your head. i much prefer polycarbonate plastics for logical reasons. i've been using my gs3 for a year without a case and it looks just like new. if i want to be flashy, i'll wear my nicest watch. my phone is for functionality, so the gs3's build is par for the course. The 45 total second battery swap of a GS3/4 (thanks for flexible plastics) compared to 3.7 hour charging for the HTC One (thanks to a solid metal frame) is all that really needs to be said on the matter. case closed. argument over. shup up. go away.

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