While I have loved my DiNotte 140L tail light for a few years now it has been a mixed relationship due to the mounting. If you are not familiar with these lights they are extremely bright AA powered LED lights with a very simple O-ring mounting system. While elegantly simple the mounting requires attachment to a round tube, i.e. handlebars, seat post or frame tubes. Not so easy when you have an assortment of racks and bags that can block the light from behind defeating the whole purpose. I have a Old Man Mountain "Cold Springs" rack on the back of my Rawland. This rack combined with my saddle bag has always left me a bit challenged with mounting solutions that leave the light visible, yet allowing for a secure place to mount the battery pack and panniers.
Then I had my eureka moment while modeling ideas with a short piece of scrap dowel. I will expand on my love of dowels and wood for prototyping in a future post. This time I only needed a short piece less than 2 inches long, drilled a hole through the center, and filed some grooves in the top side for O-ring retention. I ran a long M5 bolt through the mounting track on the rack and bolted the mount between the rack and wheel.
I used the light this week in the rain on multiple rides, and it worked fantastically. The cord is the perfect length to put the battery pack into the side pocket of the carradice bag, and everything has stayed in place.
This light when mounted well will not blind approaching motorists but they will have little excuse to not see you. I have found that even on the lower powered non-blinking settings cars still give far wider birth when passing then with any other tail light in my collection. Hopefully this or a similar solution can be adapted to help you better mount your own tail light far a safer night ride.