Fake CR2032 Battery

This is a fake/dummy battery that allows you to use any larger battery (eg AA or AAA) instead of the low-capacity CR2032

You will need

• 3D print "part +"
• 3D print "part -"
• copper washer (used as "+ contact")
  • M14x20x1 - https://s.click.aliexpress.com/e/_DeE0J1T
• brass disc (used as "- contact")
  • 15x0.5mm - https://s.click.aliexpress.com/e/_Dc7gWkl
• super glue
• soldering iron
• a battery holder or any power source/wires
  • 2AA - https://s.click.aliexpress.com/e/_DlNOaUN
  • 2AAA - https://s.click.aliexpress.com/e/_DCHOEwD

Optional

• file
• sandpaper (any grit)
• clamp
• third hand

Instructions

See images for more details

1. Prepare and print all parts (PLA, 0.2mm layer height)
   • Make sure your disc and washer are flat. They sometimes arrive a bit bent.
2. Superglue the brass disc (- contact) to the flatter side (the one that was on a printer bed) of "part -". Make sure the parts are centered.
   • (Optional) After it is glued sand slightly the plastic - part (the one that was on the top during printing) to make it flat
3. Solder the red/+ wire to the copper washer (+ contact)
   • file the soldering spot to make it smaller and not exceed the battery diameter
4. Push the black/- wire through the washer (soldered in previous step) and solder it to the brass disc (- contact)
5. Superglue the washer and the "part -" together. Make sure the parts are centered
6. Superglue the "part +" together with the rest. Put some extra glue on the wires to fix it properly. Make sure the parts are centered. Clamp it tightly together.
7. Done. The connection is not perfect. You might need to be adjusted it a bit. Sand it a or add some paper to make a tighter contact.

Some notes about batteries

The capacity of CR2032 battery is 220mAh. Todays low-power devices have a power consumption on the levels of battery self-discharge, so the capacity is not a big issue, however devices with occasional high current peaks (Remote controllers, ZigBee/BLE devices) cannot use full capacity of the batter due to voltage drop caused by high internal resistance of the battery. Variable quality of CR2032 batteries even from branded manufacturers makes designing such devices challenging. You can google for "Microchip AN1416" for more details.

Larger batteries (AA, AAA) on the other side have much better parameters.

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