IIRC L91s are 1.7v or something fresh, so the higher voltage will make the driver go into direct drive since the Vf of the LED is lower then the input voltage of the batteries. That could explain the higher output on low.
IIRC L91s are 1.7v or something fresh, so the higher voltage will make the driver go into direct drive since the Vf of the LED is lower then the input voltage of the batteries. That could explain the higher output on low.