The LG G6 comes with a 3,300 mAh (12.71 Wh at 3.85V) non-removable lithium-polymer battery. This battery is a significant 18 percent larger than the G5, though it loses its removable functionality. The G6 is the first LG flagship smartphone to ditch the removable battery in favor of a fully-sealed unit, and you can see the larger capacity this move has brought.
Across the board, the G6 packs better battery life than the G5, though this isn't a huge surprise considering how poor the G5's battery life was. The gains aren't massive by any stretch, and due to the larger display, the G6 actually fails to reach an 18 percent battery life improvement in most tests. In PCMark, for example, the G6 lasted only 14 percent longer, with this margin falling to just five percent in browsing tests.
The improvement in battery life is welcome relative to the G5, however the G6 isn't a battery life beast. It falls in the middle of our charts, and gets handily beaten by the Exynos-powered Galaxy S8+ and the Google Pixel XL, though both those phones are larger.