1 #+TITLE: AA and AAA battery tester
2 #+AUTHOR: Svjatoslav Agejenko
5 * (document settings) :noexport:
6 ** use dark style for TWBS-HTML exporter
7 #+HTML_HEAD: <link href="https://bootswatch.com/3/darkly/bootstrap.min.css" rel="stylesheet">
8 #+HTML_HEAD: <script src="https://cdnjs.cloudflare.com/ajax/libs/jquery/1.11.3/jquery.min.js"></script>
9 #+HTML_HEAD: <script src="https://cdnjs.cloudflare.com/ajax/libs/twitter-bootstrap/3.3.5/js/bootstrap.min.js"></script>
10 #+HTML_HEAD: <style type="text/css">
11 #+HTML_HEAD: footer {background-color: #111 !important;}
12 #+HTML_HEAD: pre {background-color: #111; color: #ccc;}
16 + DISCLAIMER: I DO ELECTRONICS AND 3D DESIGN SOLELY AS A HOBBY. THERE
17 COULD BE ERRORS THAT CAN RESULT IN ALL KINDS OF DAMAGE. USE THESE
18 DESIGNS AT YOUR OWN RISK.
20 + This design is released under Creative Commons Zero (CC0) license.
24 - Homepage: https://svjatoslav.eu
25 - Email: [[mailto://svjatoslav@svjatoslav.eu][svjatoslav@svjatoslav.eu]]
28 - [[../../index.html][Other physical projects in this repository]]
29 - [[https://www.svjatoslav.eu/projects/][Other projects hosted at svjatoslav.eu]]
34 [[file:make,%202.png]]
36 Simple rechargeable Ni-MH battery tester. The problem with those
37 batteries is: right after you take them out of charger, voltage level
38 at their terminals is good. But some old batteries will get
39 empty/discharged way too quickly under normal load. This device is
40 intended to discover old batteries with reduced capacity.
42 Freshly charged batteries are tested under high load for short time by
43 shorting battery + and - terminals using 5 ohm power resistor
44 (R1). Simultaneously battery voltage is being measured while under
47 [[file:electrical%20schematic.png]]
49 I use vintage analog voltmeter. Instead of power resistor I use
50 Nichrome resistance wire. Test/measurement button should not be
51 pressed for long because power resistor gets hot quickly and battery
52 is being quickly depleted during measurement.
56 + Body: [[file:body.png]]
57 + Cover: [[file:cover.png]]
60 + [[file:bodyAndCover.FCStd][FreeCAD project]]
61 + [[file:body.stl][body STL file]]
62 + [[file:cover.stl][cover STL file]]
64 + PS: While this device is interesting to build, still you can just
65 use ordinary ammeter that can handle battery generated current.