A quick and easy repair/upgrade to my nixie clock. I hate NiCad batteries with a passion. Join me as I install a nice peaceful NiMH battery in place of it. Enjoy the back of my hand for half the video while I block what I am doing due to bad camera positioning! ;)

A NiMH battery is not automatically a drop-in replacement for NiCd in equipment that charges the battery internally. Suitability depends on the charging current and charge-control method because NiMH cells have different overcharge and trickle-charge requirements. This replacement worked in this clock, but anyone repeating the repair should check the charging circuit and the specifications of the replacement battery rather than relying on voltage alone.

By 17 April 2022, the battery had been replaced again, in late 2021. IN-12B has a dot; IN-12A does not. Some facts about the power supply, mostly for my own future reference:

  • ID: 2.5 mm
  • OD: 5.5 mm
  • Length: 9.5 to 11 mm
  • Clock input: 7.5 to 9 V DC
  • Supply current rating: 300 mA or greater
  • Polarity: centre positive

I’d ordered an XP Power ACM12US09, which I hoped would do the trick nicely. At the time, I hadn’t found a Mean Well AC-to-DC power adapter with a 2.5 mm plug, only 2.1 mm. They offered an adapter, but then I’d need to remember what the adapter… adapter is for.

Sources