Behind the Desire 816’s rear cover is a 2,600 mAh, 9.88 Wh non-removable battery: identical in size to the HTC One M8. The less powerful SoC and lower display resolution should result in similar battery life between the two handsets, considering the Desire 816’s larger screen.
During my time using the Desire 816, I found the battery life to be pretty good. The handset appeared to last especially long on Wi-Fi networks, but wasn’t as strong when I took it out of the comfort of my house. At the end of a typical day’s usage I was left with around 40-35% of the charge remaining, although this can fluctuate depending on usage patterns.
Of course you’ll get a much better idea of the battery life from our typical tests, the results of which you can find below.
As I anticipated, the Desire 816 delivers around the same battery life as the HTC One M8 in our video playback battery test.
The Desire 816 is a strong performer when it comes to Wi-Fi browsing, but falls behind when you're using it on LTE networks. The results shown above fit well with my general experiences using the device as a daily driver, where keeping it on Wi-Fi lead to great battery life.
There's not a lot of graphics power in the Snapdragon 400 SoC, at least compared to high-end smartphones, resulting in great battery life while playing 3D games.
Like other recent HTC products, the Desire 816 comes with both a basic power saving mode that downclocks the CPU and dims the display, as well as Ultra Power Saving Mode. When you put the device in Ultra Power Saving Mode, all the non-essential features are disabled and the homescreen becomes a grid of six icons, leading to the most critical features like the phone, messages and calendar.
Essentially in this mode a smartphone turns into a featurephone, allowing the device to last for hours longer when the battery is at critical levels.