Updated the design to center the doubler, and to include wall hanging holes as well to help in mounting, etc. Also, the battery holder has been recessed into the surface of the mount to build strength, and make it easier/faster to print. Battery end caps and end cap supports have been redone as well to make it more supportive when the screws for the wires are tightened.
I have added extra gussets to the end of the battery to prevent flex when the bolts are tightened, and added a double batter version!
I am have been working on remote devices that will run on battery power, and this battery case and board mount are a solution to having a manageable, maintainable remote sensor.
Uses 2 M3 nuts and bolts per battery for terminals - attach wires to the bolts and you have connections! In the case of the double case, you can run the batteries in series or parallel.
Mounting posts are set up for the Adafruit Feather Doubler - https://www.adafruit.com/product/2890. I use this board to add and remove Feathers - you can use anything that fits this board, including LoRa/packet radio units, ESP8266's, and ESP32's. There is additional area for additional boards as necessary