Operator's manual for DW926K-2 is here. It doesn't specifically address solid red light, but that's what mine does when I first put it on, so solid red indicates that it is charging.

If it is flashing the red light with two fast blinks followed by a
pause. This means the power source has out of spec for the charger (such as a generator not producing electricity at 60Hz).

If the red light flashes long, then short, you're in Hot/Cold Pack Delay mode which means it won't charge the battery until its temperature has stabilized.

I hope this helps! If so, please vote. Thanks.