Last week I mentioned that Hackaday is putting on a coin cell challenge. While you would logically first think of the CR2032 battery as the subject, the contest is actually open to anything that could reasonably be called a “coin cell.” One such battery is the ML2032, which features the same footprint as the CR2032, but is rechargeable.
While that sounds good in theory, you’ll also need some way to actually charge these batteries, which Tindie seller bobricius of Permi Technology provides with this handy charger. As he notes, you can find cheap chargers from other outlets, but if they happen to say “LIR2032” on them, they will actually end up destroying these cells because the LIR uses a different battery chemistry than the ML, which uses Lithium Manganese Dioxide. But the ML2032 is a worthy consideration since they’re a bit more earth friendly than their traditional counterparts.
Besides actually being designed for the batteries you’ll be using, this unit plugs into any USB charger without the bulk of an extra wall wart or similar. According to the description, it takes 24 hours to charge an ML2032. Per the next question that you’re likely forming after reading this, it’s “only for use with rechargeable coin cells!”