CR2032 coin cell to two AA batteries adapter
18.5x longer life span
Due to the small size of the CR2032, they don’t contain as much power as AA batteries.
There is a way to replace a small CR2032 battery with two high capacity AA batteries for a much longer (18.5x) life span for your sensors.
How it works
A single CR2032 is 3V, two AA batteries in series are comparable, 2.4 - 3V (depending on the battery model).
- Place two (rechargeable) AA batteries in a case with a female USB port.
- Connect the male USB cable from CR2032-to-USB adapter (aka battery eliminator).
- Place the other end, with the fake CR2032 battery, in the sensor. Probably you can’t close the cover of the sensor anymore without making a hole in it to guide the wire outside.
The downside is that the cover of the sensor doesn’t close correct anymore, because of the two wires to the USB connector. You have now a huge battery block attached to this sensor. That’s why it isn’t a solution for each CR2032 powered device. I use this solution myself for temperature sensors which lay on top of some bedroom closets where you don’t see them and not easy to reach. For these cases, the longer battery (and use of regular AA batteries) life is more important than the small and compact look.
The amount of ampere is now increased to 4200mAh compared to 225mAh.
That’s 18.5x more than the single coin cell was!
Yes, you have a big box attached to your sensor now,
but when you use it for already hidden (temperature/contact/..) sensors, this is not a problem, right?
To create this
You need these three items, plug them together, and you’re done:
-
A dummy CR2032 to USB adapter (AliExpress) (AliExpress) or (AmazonUS)
-
A USB battery case for TWO AA batteries (AliExpress) (AliExpress) or (AmazonUS)
-
(At least) two (Eneloop) AA batteries (AliExpress) (AliExpress) or (AmazonUS)
The result
Still portable, but now with much longer battery life!
And you don’t need to buy new CR2032 batteries, just recharge the AA batteries,
and the sensor can do their job again for years!
Rechargeable CR2032
Did you know there are also rechargable CR2032? They are called LIR2032.
You can find more information about them here.
See also my Zigbee - Best Buy Tips for battery powered Zigbee sensors.
And my Batteries - Best Buy Tips page.