Question Motherboard light pop up at night (unplugged)

[Milan0305]

Why is my motherboard light show up at night ? It does this more time at night when it's unplugged. I know there CMOS battery. But why is that just random?

 

[Ralston18]

Make and model motherboard?

What color is the light? Location?

By "unplugged"you mean that the power cord to the PSU is taken out of the wall outlet?