This is my version of a voltmeter for Anet A6. I design and upload 5 different lid for different meters, use the one you like... the link and photos are below in custom.

The mount will be attached to the right Z stepper with the original stepper motor screws.

PD. The lid #3 have 2 hole for switches so you can add and other mod beside the meter. you can put a on/off button and a fan or led button too.

The lid #5 is just a control panel for power, fan and led with a small voltage lcd display port.