The Incredible Shrinking Coin Cell Battery Pack

How’s it going with your project for the coin cell challenge? You can only use a single one, but Hackaday alum [Jeremy S Cook] has a great way to package coin cells into a sleek little power packs whether you need one, two, or even four.

[Jeremy] is building a wireless Wii nunchuk, so he needs a small battery that won’t short out or get punctured in the confines of the controller body. A single coin cell holder is already a bit bulky, and he needs to use two in series. He thought, why not try shrink wrapping them together? The only downside here is that the biggest tube that came with your average heat shrink multi-pack is probably a bit too tight to fit around them, so you might have to buy more (aw, shucks!).

After trying a few ways to make a good connection between the leads and the bare coin cell faces, [Jeremy] settled on generously stripping stranded wire and wrapping the long strands around the end to form a conductive swab. This slides in nicely between the coin cell and preshrunk tube. A little more heat will make a good connection, and some hot glue secures the wires. Click past the break for his build video and the other connection methods he tried. Have you come up with something better? Let us know in the comments.

Stray a bit further from the bench and you might come up with something like this googly eye battery holder we saw a few months ago.

17 thoughts on “The Incredible Shrinking Coin Cell Battery Pack

  1. This is how the laptop manufacturers make their replaceable RTC battery packs.
    They usually use a thin plastic film that thickens to 0.25mm when shrunk and thus has almost the exact footprint of the cell and cable.

  2. I did something similar when I bought AD584 voltage reference on eBay. It has slot for some weird 15V battery that is hard to find and not very cheap. Luckily CR2032s and heatshrink are dirt cheap, and problem was solved. Small neodymium magnets were inserted between cells to hold whole thing together until shrunk, and also to adjust “battery pack” to required length.

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