Answer:
The battery icon is slowly blinking: Battery level is below 15%.
One grid is solid white: Battery level is between 15% and 30%.
Two grids are solid white: Battery level is between 30% and 60%.
Three grids are solid white: Battery level is above 60%.
You can also check the exact battery percentage shown as a number directly below the battery icon.
For example, if you see “99” below the icon (as shown in the image), that means your battery is at 99% — nearly fully charged.