Remix of XYZ.Thought's nice caddy to make it slightly wider, add a base with some drainage, and stretched the handle designed for convenient carrying of batteries and accessories to the work site.  This model is not perfect but functional.

Printed in PETG with 3 walls and 15% sparse infill.  Went honeycomb sparse infill on the handle.
Prints easily. The original noted no supports, but I printed flat and used automatic tree supports for the battery latch areas and the drainage features on the bottom. 

Assembly -used two M4 x 12mm with threadlocker to mount the handle.

It gets hefty with many bigger batteries...did not load test it fully loaded with many large batteries (but did work with it as shown). I thought about changing the bottom and other features to support other print orientations for load vice layer adhesion, but end the end left it as is. Use at your own risk...strengthen as needed.

Finally, pictures show the irreverent use of team red filament...go with what you got  :) 
Thanks to all who contribute :)