Battery Life
Inside all models of the new Dell XPS 13 is a 56 Wh non-removable lithium-ion battery, which is the same size as the battery in the previous model. Improvements to the efficiency of the Skylake CPU should improve the battery life of this laptop compared to the early 2015 variant, but there will still be a noticeable gap in stamina between the 1080p and QHD+ models.
Unfortunately, the two XPS 13s I've received have been of different resolutions, so it's hard to draw any precise comparisons on how battery life compares moving from the old 1080p model to the new one. However, it's still safe to say that the 1080p model delivers around two to three hours more battery life, depending on the workload.
Across our main laptop battery life benchmarks, the new XPS 13 with its QHD+ display sat several hours behind the older XPS 13 with its 1080p display, as I anticipated. Battery life from this model is good without being outstanding, although I expect the 1080p model has still retained its excellent battery life.
The Surface Book does outperform in the XPS 13 in out battery tests, although that isn't hugely surprising considering it's a larger laptop with a bigger battery. The margin in our web browsing test isn't huge, at just 30 minutes, which is a great result for the XPS 13 as the Book has fantastic battery life across the board.