Snapdragon 835 is a battery-efficient and powerful chipset so, these are perfect for Pixel 2/XL devices. It depends on the device and chipset, we cannot control battery drain completely as these wallpapers perform some heavy OpenGL tasks in the background. What will be the impact on battery life after using these wallpapers? These wallpapers are designed according to the Snapdragon chipset so, I can't do much in this. Not working on Exynos, Kirin or any other chipset? Please contact your ROM developer or device manufacturer.