Power supply with Coin Cell Battery for arduino nano + RFID reciever

I am new to Arduino and I have managed to create a arduino [u]nano[/u] with a soldered [u]RFID tag[/u] on it (FST1000A). Since this entire setup is very small i was hoping to be able to supply power of at least 9-12 volts using either coin cell battery or A23 battery to maintain the compactness of the device.

The idea is to make it portable and small. Therefore I wanted suggestions on whether it is possible and how long will it last, ( hopefully at least 1 month). I am open to suggestions and critiques and any help.

I currently power it using a portable battery charger but that is too bulky. The chip itself uses 4MA and nominal supply is 5V but I want to supply more than 5 (hoping for 9 V or higher). Please help me out here guys

You will need to use a Lipo Battery and it will likely be lager than you electronics.

If you use three CR2032's in series for 9 PV they are about 225mah and so you will get about 50 hours maximum at a 4ma draw. The A23 is only ~55mah so less than 12 or 13 hours.

Why do you need 9v?

An Atmega 328 will happily run on 3v at 8MHz

Have you seen Nick Gammon's power saving tutorial


If you need really low power consumption the pro-mini is a better choice, as it doesn't have the power-hungry USB chip


I think you mean 4mA (milliAmperes) not 4MA (??MegaAmps??) I second the query about your wanting 9V. Arduino does not need 9V. I don't know what is in your RFID unit though. What are its specifications ? I confirm the comments that tiny batteries won't last many days. Could you not pass two wires into it from something like the 5V charger?

nilankan: I am new to Arduino and I have managed to create a arduino [u]nano[/u] with a soldered [u]RFID tag[/u] on it (FST1000A).

Sounds like a new arts and craft movement.

Firstly, where are you getting 4mA from? An "active" without sleep ATMEGA328 needs about 40mA usually at idle but can be put to sleep to only use micro-amps.

Is there a reason why this project could not be ported on to a bare ATMEGA328 to avoid the need for the other components on the Nano that use current...like the voltage regulator and USB chip?

Seeing some code and actually knowing what the device is intended to do may allow for some scope of cutting down the power usage dramatically.

An ATTIny85 on a CR2032 cell could last years...if all it had to do was wake up once a day and say add two numbers together...but until we know what you are trying to achieve we can not really help?