AA and AAA battery tester

• DISCLAIMER: I DO ELECTRONICS AND 3D DESIGN SOLELY AS A HOBBY. THERE COULD BE ERRORS THAT CAN RESULT IN ALL KINDS OF DAMAGE. USE THESE DESIGNS AT YOUR OWN RISK.
• This design is released under Creative Commons Zero (CC0) license.
• Author:
  • Svjatoslav Agejenko
  • Homepage: https://svjatoslav.eu
  • Email: svjatoslav@svjatoslav.eu
• See also:
  • Other physical projects in this repository
  • Other projects hosted at svjatoslav.eu

Simple rechargeable Ni-MH battery tester. The problem with those batteries is: right after you take them out of charger, voltage level at their terminals is good. But some old batteries will get empty/discharged way too quickly under normal load. This device is intended to discover old batteries with reduced capacity.

Freshly charged batteries are tested under high load for short time by shorting battery + and - terminals using 5 ohm power resistor (R1). Simultaneously battery voltage is being measured while under load.

I use vintage analog voltmeter. Instead of power resistor I use Nichrome resistance wire. Test/measurement button should not be pressed for long because power resistor gets hot quickly and battery is being quickly depleted during measurement.

• Body:
• Cover:
• Download:
  • FreeCAD project
  • body STL file
  • cover STL file
• PS: While this device is interesting to build, still you can just use ordinary ammeter that can handle battery generated current.