Because the identify suggests, activating this setting places your machine into low energy mode. And it actually does work, providing you with about three hours of additional battery life. In case you are anxious about your battery not making it by means of the day, that is the setting to activate.
Nevertheless, it achieves this by turning off or decreasing mail fetch, background app refresh, computerized downloads, and a few visible results.
iOS gives to activate Low Energy Mode when your battery goes under 20 p.c and 10 p.c, and can flip it off when the machine is charged to 80 p.c.
You can even flip this on manually, both from the Management Middle panel, or from Settings > Battery.