Modular battery storage and test device

Place up to 40 AA or AAA batteries inside the storage module. Add more storage modules. Attach the testing module to a storage module. Quickly check the voltage of each battery under a load of approx. 150mA.

Design goals:

• Modular setup: Combine one test module with multiple storage modules
• Flexibility: Storage modules can take AA and AAA batteries (with AAA adapter)
• In-place testing: No need to remove the batteries
• Speed: Attach test module to a storage module within a second
• Battery probe comes with integrated cable management
• No external on/off switch: The test module switches on automatically when the battery probe is removed
• No screws,  no support, easy to print: Designed for 0.3 mm layer height

Due to the built-in electronics, there is a bit of soldering work.

What you'll further need:

Wiring diagram (test module):

Some hints:

• The top-cover of the 9V battery compartment is glued in place with a tiny drop of superglue after installing the battery connector.
   
• Protect the load resistor with some shrinking tube.
   
• The upper part of the battery probe consists of two bodies (outer ring and spindle) which are print-in-place: The outer ring must be able to rotate freely around the spindle. The probe wire must be passed through the outer ring and spindle and finally soldered to the contact copper wire of the lower part of the battery probe.
  After all the lower part of the battery probe must also be glues to the upper part (spindle). See below.
   

I used PLA (Prusament Galaxy Black) with 10% infill for printing. The 3MF file contains all part with the correct orientation. Adjust temperatures to your needs and make sure you print the model with 0.3mm layer height!

Here are some pictures from the assembly:

If the model generates some resonance, I'll provide more detailed assembly instructions on request.

  - enjoy -