Wired stick up cams back up battery levels

I wave 3 wired stick up cams , 3rd generation, they all have back up batteries in them, but does anyone know how to tell what the battery levels are ? I just had to call Ring about a problem I was having and they advised me that my batteries were at critical level of 1%, however, I’ve had no notification of that and there’s nowhere in device health that I can see the battery level, does anyone know how you can check these levels when they are wired devices?