Dell Latitude E7450/7450 (Late 2014) - Manual (Page 50)

Alternately
blinking amber
light and white
light An unauthenticated or unsupported non-Dell AC adapter is attached to your
laptop.
Alternately
blinking amber
light with
steady white
light Temporary battery failure with AC adapter present.
Constantly
blinking amber
light Fatal battery failure with AC adapter present.
Light off Battery in full charge mode with AC adapter present.
White light on Battery in charge mode with AC adapter present.
50