If you decide to use an A23 battery (small cylindrical 12V) in a project you will discover that there are no A23 panel mount holders available. If you don’t want to open your enclosure to change batteries, here’s a suggestion. The A23 fits in a Bussmann HPF fuse holder but is slightly too short. You can use a 3/8″ (or 100 mm) diameter brass disk, 0.280″ (or 7.1mm) long, dropped into the panel side of the holder to extend the back contact. Insert the negative end of the battery into the cap where it is held by friction and screw in the cap with the battery positive end against the brass spacer. The internal spring will compress about 0.035″ as the cap is screwed in to maintain battery contact. The Bussmann terminal labeled “LINE” will then be the +12 terminal.
Bussmann makes variants of the HPF holder for non-standard fuses that still require a (shorter) brass spacer but the plain HPF is the most common and easiest to find. allfuses.com had by far the best price for these I could locate.
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