[wasayanwer97]

The purpose is to know when it is time to switch batteries for the best performance in competition or practice , without having to constantly rely on a multi-meter.

Timing wise, the best time to switch out a battery is before every match.
That is the procedure most teams (that I know of) try to follow.

Aside:

There are existing solutions to this issue already. Cross the Road already sells a battery beak, but those are quite expensive. In addition, the driver station also already has a voltage monitor on it while the robot is in operation.

However, don't be completely discouraged. A quick, easy to check battery meter might still have a place if you can get it to a low enough price point.

The idea and drive to create a new product is awesome to see. However, as a rookie team, you need to evaluate whether or not time might be better spent trying to establish relationships with local companies as sponsors.