So here is a quick video showcasing my battery box mods. https://youtu.be/HXRzNNS9hTo
I created these boxes because my droid's drive gear melted after 30 minutes of heavy use. The previous design had no cooling. I also reprinted the drive gear in nylon which has a 250C print temp vs the PETG I was using.
I designed a false-back output vent that hopefully looks like it could be part of the astromech design philosophy. Right now, they are powered off of the 24V drive system and have a separate switch to power them. I want to make them activate as needed based on the battery box internal temperature (or motor case temperature). This way, they would not run continually.
Additionally, I added clips to attach the boxes so they come on and off without tools. This is super handy for maintenance. I used 24V 20mm fans from https://www.amazon.com/gp/product/B01MU4PU9K/ref=oh_aui_detailpage_o07_s00?ie=UTF8&psc=1. They mount with M4 25mm bolts. I used #4 1/2 inch wood screws to mount the back air duct panel to the case. Additionally, I mounted the clip with embedded 4mm square nuts and 20mm M4 bolts.
I included vents for air intake behind the battery straps. However, I decided to block them with the included plate. This way I believe more air will flow nearer the motor. I am also going to add some cooling fins to the motor case.