That E-Cig Battery Probably Fits Into Sunglasses

This particular e-cigarette is a little bigger than a typical cigarette, with a matching battery.

E-cigarettes use electrical power to rapidly heat and vaporize a base liquid such as propylene glycol, and that power comes from a battery. These devices are functionally straightforward but it can be a messy process on the inside. Thankfully though the batteries can be salvaged once components like heating elements either gum up or burn out.

[facelesstech] decided to use the battery from an e-cig as the power source for a smart sunglasses project, which uses two RGB LED rings to put on a light show. Opening up the device it was discovered that the battery was a straightforward lithium-polymer cell, in AAAA size. If you’ve ever torn open a 9 v battery and discovered the six diminutive cylinders inside, an AAAA cell is about the same size as one of those. However, the battery from the e-cig is both rechargeable and has a nominal voltage of 3.7 volts, which can happily drive a microcontroller project. The small battery fit nicely into one arm of the glasses, and when covered with heat-shrink, was hardly noticeable. The battery charger doesn’t fit inside the glasses, but one can’t have everything.

The ability of an e-cigarette to pump out clouds of vapor has led to some interesting hacks. One such is a DIY portable fog machine, which opens all kinds of doors for costuming applications.

20 thoughts on “That E-Cig Battery Probably Fits Into Sunglasses

    1. For a moment, while reading your link, I was confused with PEG.
      PEG is the effective ingredient used in “Go Lightly” (TM).
      (used to flush the bowels for a colonoscopy)

  1. It is incredibly to find vape juice (the liquid referenced at the beginning of this article) that is has propylene glycol as the “base liquid” it is usually mixed with vegetable glycerin, often at a 30:70 PG to VG ratio.

  2. Cool to have a source for cylindrical lipo cells. A quick check on e-bay finds ample replacement vape pen batteries for a few bucks, although they’d have to be extracted from some type of housing. Wonder what the discharge rate of these are. Will definitely keep this in mind if/when I have a project that would benefit a cylindrical battery.

    1. Years ago when the cig shaped vapes were hitting market saturation, I got a bunch of replacement batteries for $1 or so with free shipping from Fast Tech.
      When the cheap threading wore out, or the battery died, I’d tear it apart.
      Aluminum enclosure, plastic end cap with a small PCB for the LED and “breathing” sensor.
      After that, it was just a tiny 80-110 mAH LiPo cell wrapped in kapton tape and some wires.

      For the discharge rate, they would run on 2 ohm heating coils.
      So assuming 4.2V fully charged, that would be about 2.1A max discharge rate.
      Due to the capacity, obviously they were meant for short burst discharge. But as crappy as they were, they still worked for a bit before needing a charge. Would be much better suited for other projects, especially if they’re low discharge.

  3. A one or or two ohm load quickly trashes those tiny cells anyway. Get them new, still made of dubious stuff but usable.

    I just hacked two 18650 cells onto a digital volt-set vape “pen”. It’s still pocketable but gives predictable results on and on. It hasn’t needed a charge yet.

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