Just how long is a 2700mAh battery supposed to last on a Nexus 5x? Some websites report 17hrs and at least one said 6hrs. Well, 6hrs is just plain un-usable, however, since it was only one review I have to stand with the others. One thing to keep in mind is that the size of the battery is only one side of the equation. It’s almost as important to know what the drain rate of the electronics/software and the effect of ambient temperature.