Powering Arduino UNO, Data Logging Shield (Rev B) and RFID Shield


I was planning on stacking an Arduino UNO, Data Logging Shield (Rev B) and RFID Shield on top of each other and was wondering if a 3V Lithium Coin Cell Battery that gets inserted into the Data Logging Shield would be good enough to power all three components when the Arduino is not wired to a computer.


You answered your own question. You want to know if the 3V coin cell is good enough to power the 5V arduino? Probably not.

Not to mention the battery is only wired to the RTC VBat pin and doesn't go anywhere else.

Sorry if this is a dumb question, but what is the purpose of the Arduino when it is connected to other shields or sensors? Is it to just connect to a computer in order to program the various components together?

The reason I'm asking is to know whether it is important to have the Arduino powered when it is being used wirelessly or is it just important to have the shields powered?

Thanks for your help!

The shields are peripherals (like a printer for a computer). The Arduino is the processor working with the shields (like the computer). You can't use the printer without a computer. You can't use a shield without an Arduino.

I would poke around this site (Resources and Products tabs above) and read up. The Arduino requires C/C++ programming knowledge.

No... The "rumor" is that a 9V battery doesn't last long enough for anything useful, so a coin cell (or two) isn't going to have any useful life, if it works at all... (I've never tried running an Arduino off a battery, except for a car battery, and I've never made the calculations.)

You may be able to "sleep" the Arduino depending on what you're doing and/or you can build a simpler version of the Arduino (with fewer components on the board) to get more battery life. I don't know anything about the shields you're using.

If you don't have one already, I'd suggest you get a multimeter and measure the current (with and without with shields). That will give you a starting-point for calculating battery life (from the battery's mA-hr rating) and you'll know where the current is "going" if you want to work-on reducing the current.