Since the case is transparent, some of the led light is routed to the top of the controller, but a good amount bleeds right though.

My husband has an light that takes the same batters and they work just fine in it for over an hour

The negatives (an the reasons for loss of a start):-The LED indicator lights are blindingly bright.

: Take the controller apart and put a little bit of tape over the acrylic that is routing the led light.