#+TITLE: AA and AAA battery tester
#+AUTHOR: Svjatoslav Agejenko
#+LANGUAGE: en

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* General
+ 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: [[mailto://svjatoslav@svjatoslav.eu][svjatoslav@svjatoslav.eu]]

+ See also:
  - [[../../index.html][Other physical projects in this repository]]
  - [[https://www.svjatoslav.eu/projects/][Other projects hosted at svjatoslav.eu]]

* Project description
[[file:make.png]]

[[file:make,%202.png]]

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.

[[file:electrical%20schematic.png]]

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.

[[file:assembly.png]]

+ Body: [[file:body.png]]
+ Cover: [[file:cover.png]]

+ Download:
  + [[file:bodyAndCover.FCStd][FreeCAD project]]
  + [[file:body.stl][body STL file]]
  + [[file:cover.stl][cover STL file]]

+ PS: While this device is interesting to build, still you can just
  use ordinary ammeter that can handle battery generated current.