We are all familiar with the dashboards of our motor cars and the usual layout of controls - so much so that we can generally get into a strange car and tell at a glance what speed we are doing, what the engine revs are, and how much petrol is in there. We'll get some indication of the engine temperature and at least a warning light for the presence - or absence of oil. Enthusiast cars can tell us the state of the electrical system, cooling system, and many other measurements.
Camera systems can be similarly complex but there are few agreed symbols to let you know what the engineers know. Apart from the on/off button and the little playback arrow, there can be a real designers and artists festival in the choice of the icons. One of the worst is the one that deals with the battery life.
It can be a little symbol of a battery, or a percentage of charge, or a complex diagram to track total battery life. It might be white to start with, then turn red at some stage of the game. It might flash, or not. Unfortunately there is no real agreement as to exactly what level of electricity is indicated when any of these things occur - apart from the sensible manufacturers who state a flat percentage.
Some cameras, Like my Fujifilm X-E2 will show the charge in three distinct stages - Full at three bar, half? at two bar, and single bar means very few operations left before it goes flat. It's not really exact, but at least you can get over 50 shots at two bar stage - I did so yesterday.
Hard to tell the manufacturers what to do, but I would like to raise a tiny hand for standardisation in this measurement - if you can give us a percentage we can plan better what action to take - ignore, panic, or recharge.