DIY Clothespin Coin Battery Charger - LIR2032

Using rechargeable batteries is good for both our wallets and the environment!

I made this small project because I have an inexpensive caliper that consumes lots of CR2032 disposable batteries.

To produce less waste, I started using LIR2032 batteries. They have the same shape as CR2032 but are rechargeable.

In this video you can see how I built the charger for these particular batteries.

In this guide I will include all the information that is not in the video.

Happy reading!

Supplies

LIR2032 + TP4056

LIR2032s are lithium-ion batteries. They have a very low capacity; the ones I am using are 40mah.

The TP4056 module is very inexpensive and perfect for charging lithium batteries.

I do not recommend using it directly to charge low capacity batteries because the module has a maximum charging current of one ampere.

Definitely too powerful a current for an LIR2032.

Luckily, by replacing resistor R3, we can adjust the charging current.

For my project, I used a 47k resistor, so the charging current is lowered to about 30mah. This allows us to safely charge the battery for about an hour.

As you can see, I soldered a connector in place of resistor R3, so we can change the charging current at any time.

I attach the table found in the datasheet of tp4056, which shows the resistance in relation to the maximum charging current.

Why Did I Use a Clothespin?

Because I had it at home and didn't feel like using the 3d printer!

Assembly Instructions

I hope the video is quite comprehensive. I tried to emphasize all the steps of the construction of the charger.

For all the doubts and questions you can write a comment here on instructables or on youtube, I will answer you as soon as possible and, in case, I will add information on this page.

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