Coin Cell Gauge Card – Which CR battery is it?

A coin cell's name is its size. CR2032 means 20 mm across and 3.2 mm thick. This credit-card gauge finds both numbers, so you can identify a cell whose print has worn off, or check which one a device takes before you buy. How to use it - Holes 24, 20, 16 and 12: the cell drops through the smallest hole it fits. That gives the first two digits.

- Slots 16, 20, 25, 32 and 50 on the top edge: slide the cell in edgewise, into the thinnest slot it fits. That gives the last two digits.

- Put them together: hole 20 + slot 32 = CR2032. It covers the common ones: CR2032, CR2025, CR2016, CR1632, CR1620, CR1616, CR1220 and CR2450.

- The millimetre ruler along the bottom edge (zero on the left) measures anything else.

Print settings - PLA, 0.2 mm layers, 2.2 mm thick (11 layers), flat, marked face up, no supports. 100 % infill makes it stiff, about 12 g.

- The 3MF assigns the colours for a Prusa MMU3: red in slot 1, white in slot 2. Red is a 0.6 mm inlay, so only the last three layers swap colour. For one colour, print carte-piles.stl.

- Keep elephant-foot compensation on (PrusaSlicer default).

Accuracy - Holes are 0.4 mm over nominal and slots 0.25 mm over, because printed holes and slots come out a little narrow. First prints are being tested; I will adjust the clearances here if needed. If a cell does not go into its own slot, check your printer's XY compensation.

- CR2430 is 3.0 mm thick and reads as "32". Rare, but now you know.

Part of the same series as the Wallet Workshop Gauges (radius, angle, screw cards): same size, same ruler. Designed with AI assistance (parametric Python script, manifold3d). En français Carte jauge pour piles plates, format carte bancaire. Le trou où passe la pile donne son diamètre (24, 20, 16, 12), la fente où elle se glisse par la tranche donne son épaisseur (16, 20, 25, 32, 50) : 20 + 32 = CR2032. Marquages rouges incrustés sur fond blanc, 3MF prêt pour la MMU3, sans supports, règle au millimètre sur le bord du bas.