This is a bar-graph voltmeter for a 12V battery based on the well known LM3914 IC.
I have a 12V car battery attached to a regular 500VA UPS and, because the UPS is old and doesn’t have any management options, this is how I measure the amount of charge in the battery.
It was developed mainly because it gives a nice look to the UPS, with its red, yellow and green leds. It is also easier to read than conventional digital or analog voltmeters.
LM3914 Battery Monitor – [Link]