I needed a way to safely connect together two 12V volt batteries. Sometimes it's needed to charge a battery from another, or reset a shut-off BMS managed battery. I also need it to supply supplemental 12 volt power.

The model is designed for printing in ABS, with the parts snapping together easily

• The clearance between the lid outer wall and box inner wall is 0.3mm on all sides for a comfortable fit
• The snap dots are 3mm half spheres
  • solids emerge 0.5mm above the lid outer wall
  • holes sink 0.8mm into the box inner wall
  • snapping and unsnapping is easy, and the lid stays put

The voltmeter is https://a.co/d/4nqidkz

The quick disconnect cables are: https://a.co/d/5DuZSeF