We added a voltage display to our robot this year and it's actually one of the best additions. The reason it's nice is we can check voltage without having to be at the drive station. When we're testing normally only our drivers are at the laptop and the rest of the team doesn't know the voltage. With the little display everyone can see it. Also we can see if the battery has been changed or not very quickly when at events.
It's basically
this but in blue.