Battery Life

Obviously, battery life is one of the most important aspects of any smartphone, tablet, or other mobile device shipping today. The main point of interest for a lot of people seems to be battery life as even though we’re approaching what might be considered a full day of use a lot of people seem to need quite a bit more as battery life demands can vary dramatically from day to day. If you sit in an office for much of your day with the phone next to a charger then battery life demands are going to be relatively light but if you have to deal with a 12 hour flight with a 2 hour wait for a transfer before another 4 hour flight then you’re probably going to find that most devices are not going to have the ability to get you through a full “day” if your day of use involves 9 hours of usage between movies, games, web browsing, and other data synchronization tasks. This is obviously an extreme case but if you’ve ever done a trans-pacific flight this isn’t that far-fetched if you can’t fall asleep for at least 10 hours of the ~16 hour flight.

In order to try and test this properly then we turn to our 2016 suite of benchmarks which allow for proper characterization of battery life in fairly realistic workloads. In order to make for useful relative comparisons we disable all background tasks and set the display for all devices to 200 nits on a blank white screen for all tests. In the case of the Galaxy Note7 due to its similarity to the Galaxy S7 edge we’ve elected to run a compressed version of our suite although if time permits we’ll be adding additional results and commentary.

Web Browsing Battery Life 2016 (WiFi)

With that said we can start with the WiFi test which shows about an 8% drop for the Note7 relative to the Galaxy S7 edge. This might be surprising to some but given that the display area of the Note7 is 7% larger and the battery is about 3% smaller it’s not all that surprising as I wouldn’t be surprised if literally everything but display has identical power consumption on the Galaxy Note7.

Web Browsing Battery Life 2016 (LTE)

While the WiFi test result is pretty much in line with expectation the LTE test result is visibly different and somewhat surprising to see. It’s tempting to explain the relative difference change away as a function of Verizon and T-Mobile LTE differences but reception was fairly comparable across both test units and both were tested on LTE. Given that the Note7 has 4x4 MIMO for cellular connectivity I suspect that there are some RF front-end changes that distinguish the Note7 from the S7 edge but the RF front-end is only visible to the modem rather than the overall system so unless the modem itself can be accessed I suspect the most viable method of figuring out the changes here will be a device teardown which isn’t in the scope of this review.

PCMark - Work Battery Life

The next point of interest is going to be PCMark which shows how close the Galaxy S7 edge and Note7 are in WiFi and CPU bound tasks as they last basically an identical amount of time and have fairly comparable performance if you get both on the same version of software. Due to time constraints I would refer back to the Galaxy S7 Part 2 Review if you are interested in seeing what heavy workload battery life is like, but overall the Galaxy Note7 keeps fairly good battery life even if it isn't as great as the Galaxy S7 edge.

Charge Time

Of course, while battery life is critical we need to also talk about the other side of the equation which is how quickly it can charge. After all, if you’re stuck in an airport waiting for your connection and burn off most of your battery in the process, it’s going to be fairly painful conserving battery until you get to your destination because your phone can’t charge quickly enough to compensate for additional usage. In order to test something like this, we rely on measurements from the wall and waiting until the power draw from the wall reaches a specified level that indicates full charge has been reached. In the case of the Galaxy Note7, the charger uses QC 2.0 or Samsung’s adaptive fast charge technology depending upon the AC adapter you’re using, and internally the battery charger IC is a TI BQ25898S which contains a buck converter that can take a 9V or 12V input and step it down to the appropriate voltage for the battery with supports for current up to four amps at roughly 90% efficiency.

Charge Time

Looking at the overall charge time the Galaxy Note7 performs respectably as it reaches full charge in under two hours and takes basically as much time as the Galaxy S7 edge, which is probably not a surprise given their similar battery capacities. For the most part I think we’ve hit an upper bound here as far as charge time goes. The real challenge now is to focus on reducing the heat output and impact to battery longevity that these fast charging solutions have similar to OnePlus’ Dash Charge and Qnovo’s Adaptive Charging technologies.

Display System Performance
POST A COMMENT

202 Comments

View All Comments

  • lilmoe - Tuesday, August 16, 2016 - link

    SD820 has the power more fluidly? Yes. Better than Exynos? Ummm... No.
    If you want smoother UI and better touch response, root and change the governor to Performance, or Ondemand.
    Reply
  • lilmoe - Tuesday, August 16, 2016 - link

    I've dug a little deeper into this after I bought my GS7e (Exynos). Looks like Exynos (and it's higher count of cores) plays better than the Snapdragon with the Conservative Governor that Samsung employs to save battery life. You can manually switch it to Ondemand, Interactive, or even better, Performance (eliminating most of the UI performance differences, and increase the responsiveness of the device drastically). But battery life would take a major hit, just like every other Android device with a 1440p screen.

    What needs to fixed and optimized is ANDROID. Google still insists on doing a crappy job with their OS, just like with their browser.
    Reply
  • lilmoe - Tuesday, August 16, 2016 - link

    "What needs to fixed and optimized is ANDROID. Google still insists on doing a crappy job with their OS, just like with their browser."

    What also needs to be fixed is the "higher resolutions screen is better" mentality. No smartphone should have more than a 1080p panel for optimal performance and efficiency.

    There's absolutely no mention of the new power saving features that the new version of TouchWiz employs; like scaling down the resolution and how much more battery life you get out of that. Guess I'll have to test it myself when my GS7 gets the update. I'm soooooooooooooooooooooo scaling back the resolution to 1080p while leaving processing power intact.
    Reply
  • InspectHerGadget - Wednesday, August 17, 2016 - link

    Yes. The extra screen resolution is not worth the hit on battery life. Android and Samsung are also both to blame for poor optimisations. I had the Nokia 1520 which had great battery life, then the Note 5 which had only so so battery life, now the iPhone 6S Plus which has great battery life. On the Note 5 if I left the hotspot on it would get hot and drain the battery even when my Microsoft Pro 4 was in its case. I just felt too many rough edges on Samsung phones I had. Reply
  • jospoortvliet - Thursday, August 18, 2016 - link

    Remember, guys, amoled isn't hit by lower efficiency on higher resolution, that is only an LCD problem. Now granted the gpu and cpu have to work a little harder but 1080P wouldn't look nice with pentile and Samsung does pentile to get a better endurance/longevity and brightness out of AMOLED. I don't think they made the wrong choice here. And yes, 1440P on an LCD is stupid. Reply
  • lilmoe - Tuesday, August 16, 2016 - link

    Sorry, the governor they use is Interactive, not conservative... Reply
  • jospoortvliet - Thursday, August 18, 2016 - link

    Then it shouldn't be an issue and if it is - they shold fix the governor not switch to performance. The performance governor is barely faster at big costs. Reply
  • lilmoe - Thursday, August 18, 2016 - link

    It doesn't act like an Interactive governor would act at all, it's very slow to ramp up clock speed, and most ramps up the little cores. It's a good thing for battery life, but not as good for fluidity. Reply
  • jospoortvliet - Thursday, August 18, 2016 - link

    IMHO the on demand governor should really not be costing battery life. It was designed to be a good balance and it generally is, at least on desktop.

    Then again with such an outdated kernel with patches who knows what is in there... wish the android vendors would get their stuff up streamed more timely...
    Reply
  • grayson_carr - Tuesday, August 16, 2016 - link

    It's a conscious decision happening at Samsung. They could tweak the kernel / governor configuration so that there are almost no frame drops and slowdowns, but it would come at the cost of battery life. Samsung is aiming for the minimum performance they think their users won't be annoyed with in order to maximize battery life, which Samsung assumes is more important to the average user. Google on the other hand configures their devices so that they maintain 60 fps in most scenarios, and their battery life suffers for it. I personally prefer Google's approach because I value a smoother and stutter free UI more than a little extra battery life, but I think a lot of people who buy Nexus devices are baffled as to why the battery life isn't as good as their Samsung phone even though the battery is just as large. Those people may prefer battery life over the smoothest UI possible. Reply

Log in

Don't have an account? Sign up now