Your photos are too small for convenient interpretation. Also, the claw hammer in one of your photos is slightly disturbing my understanding of what is happening. Are you
pulling nails, or hammering them into the frame? Regardless, my 1995 K75 has a light gauge blue wire connecting the alternator to the OEM instrument cluster. When output of the alternator is sufficient to charge the battery, the alternator (charge/battery) light in the cluster is shut off.
In the spirit of posting unreadable graphics

, I have attached a photo of a Brick's wiring diagram showing the path of that blue wire (indicated by red arrows). Also attached is a photo of your BEP—turned right-side up—with an arrow pointing to the ALT (alternator) wire connection. What happens with it is up to you, of course. All this is my best guess based on current weather and mood conditions here. There are several members who have worked with this Acewell instrument; maybe they will chime in.
Good luck with your modification.