Is it bad to let the battery run out?

Hi All,
in the days before a client shoot I'll often exercise my batteries, running them flat in the camera and then charging them fully before heading out.
I'll put in the battery, hit record and let it go till it runs flat, then cycle through all of the batteries.
Is this bad for the cameras? BMPCC6kPro & UMPG2
Cheers
in the days before a client shoot I'll often exercise my batteries, running them flat in the camera and then charging them fully before heading out.
I'll put in the battery, hit record and let it go till it runs flat, then cycle through all of the batteries.
Is this bad for the cameras? BMPCC6kPro & UMPG2
Cheers