Model originally uploaded to Thingiverse at https://www.thingiverse.com/thing:4545626.
I often go shopping by bike with my child in the Thule Chariot Cross Bike trailer. The trailer has a bag on the back for storage, but this is often not enough space for all the groceries I buy and I also have the problem, that I would have to stow all the stuff again into another bag, to bring it from the cellar to our flat. So most of the time I use my Ortlieb Backroller bag for storing the items, I bought at the store. I didn't want to leave the bag at the bike during the time, I'm in the store, so where to put it. You can use the shoulder strap and put it over the handle of the trailer, but than it is dangling around. So I came up with the idea, to design a holder for the bag.
I consider this design a remix of the two linked things. I used the shape of the light holder for the attachment part and the idea with the aluminium rod, from the wall holder.
The bag sits pretty well on the holder. I would not recommend putting heavy things in it, while your pushing around the trailer, as it might tip over.
A rod with an outer diameter of 8 mm is needed. I recommend an aluminium rod, as it fits best the design of the trailer.