On my Sony E-book reader the redlight comes on while it is charging, when it is charged the light goes out. I plug it in and look at it in a few hours or overnight. Likewise my phone, when the red light goes out it's charged.
OnePlus 5 review
See the work of famous artists playing with toys
iPad Pro 10.5in (2017) review
Comment faire une capture d’écran sur un Mac ?