The Galaxy Alpha’s removable battery has a total capacity of 7.17 Wh (1,860 mAh at 3.85 V), which is 34% smaller than the Galaxy S5’s battery. This is small for a handset with a powerful SoC inside, especially considering the display is only 15% smaller on the Alpha, but a clear by-product of Samsung gunning for slimness over battery capacity.
It’s likely that the company was hoping that a reduction in display resolution and increases in SoC efficiency would offset the smaller battery. However, as you’ll see from the benchmarks below, this isn’t the case.
In our video benchmark, the Galaxy Alpha lasts significantly less time than both models of the Galaxy S5. Compared to the most similar Galaxy S5 variant, the Exynos model, the Alpha performed 22% worse; this balloons out to 31% compared to the Snapdragon model.
In our web browsing battery benchmarks, the Galaxy Alpha performs poorly. On Wi-Fi, the Alpha performed around the level of the HTC One, 21% lower than the Exynos Galaxy S5. It’s a similar situation on LTE, where the Galaxy Alpha’s battery performance sees it sit at the bottom of our chart.
In GFXBench’s battery test, the Alpha falls around the same level as the Galaxy S5. From this perspective you can see how the lower battery capacity matches up with the lower display resolution, assisted by significant throttling around five minutes into high-intensity 3D rendering. Although this result is good for the Alpha, it’s in more traditional use cases (like web browsing) that the handset falls well behind the competition.
Despite a 34% smaller battery, the Galaxy Alpha took around the same time to charge as the Galaxy S5 using a standard 10W USB wall charger. Although it charges reasonably fast for a smartphone, it does not support the same fast charging mode as the Galaxy Note 4.
Like the past few Samsung flagships, the Galaxy Alpha packs Ultra Power Saving Mode. In this mode, the phone switches to a greyscale theme and restricts access to just a small subset of the apps available on the phone. Combined with switching off background data and throttling performance, Ultra Power Saving Mode can extend battery life significantly in emergency situations.
While it isn’t meant for constant use, Ultra Power Saving Mode can give the Alpha several hours of extra use when the battery falls under 20%. If you don’t want to be as restrictive with the handset’s features, the Alpha also comes with a standard battery saver that reduces mobile data network usage when the display is switched off.