What exactly constitutes 'low battery' ?
Almost as soon as a phone goes under 50 % charge various warnings pop up saying the end of the world is nigh and that you need to get to a charging station now. Do not pass go, do not collect £200 etc.
With the laptop and chargers it is about 20-30 % when the screen turns dark and you have to plunder into all sorts of settings to readjust so you can actually see the screen - always useful I find.