Introduction: Powering Arduino With a Battery
Make your Arduino projects portable by using a battery for power. From the Uno and Mega documentation pages:
"The board can operate on an external supply of 6 to 20 volts. If supplied with less than 7V, however, the 5V pin may supply less than five volts and the board may be unstable. If using more than 12V, the voltage regulator may overheat and damage the board. The recommended range is 7 to 12 volts."
I've found that using 9V works well. You can simply connect the + end of your battery to Arduino Vin and the - end to Arduino ground (fig 1). You should see the green light on the Arduino turn on to indicate that it is powered.
It's also a good idea to attach a toggle switch in series with this battery so that you can turn your Arduino off and on. As shown in the images above, solder a toggle switch to the red lead from the 9V battery connector. Connect the black lead from the battery connector to one of the Arduino's ground pins, and connect the lead from the toggle switch to Arduino's Vin pin. Snap a battery to the connector. Now your Arduino will turn on when the switch is closed and turn off when it is open (figs 5 and 6).
Parts List:
(1x) Arduino Uno Amazon
(1x) 9V Battery Amazon
(1x) 9V Battery snap connector Amazon
(1x) toggle switch Amazon (this one is a little different that that pictured, but it will work the same)
Alternatively, you can find these 9V snap connectors with the same n-tye barrel plug as the Arduino and plug into the barrel socket on the Arduino directly:
(1x) 9V battery snap connector to barrel plug Amazon

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69 Comments
2 years ago
Will this switch work, I'm guessing it will.
Question 2 years ago
Hi! Lets say that I create and run a thermometer program on my Arduino Uno using a 9V battery as the power source. How do I access the data when I plug the Arduino back into my computer? (I do not have a SD card available) Thanks!
Question 4 years ago on Introduction
What about battery life?
5 years ago
So you program your arduino using a computer and then disconnect and run that program off of a battery? correct? I am assuming you can only run one program then ? To switch to another program you would have to start over with a computer?
Reply 4 years ago
Or you can write your program to carry out the different functions you want based on input received from a physical button or something. If you only had a few basic ones it might be worth merging that way.
Reply 5 years ago
Yes that has to be necessary, as new code has to be loaded using the loader
5 years ago
Hello sir.I have a question.When Arduino is off draw current?Please answer.Thank you
Reply 4 years ago
If you use a switch like on here, then the circuit will become physically disconnected when turned off, so no it won't.
5 years ago
Worked for me with a 4 AA battery pack
5 years ago
i want to use a Lipo battery for my RC car project,what should i do and dont?
Reply 5 years ago
You should not puncture it
5 years ago
Running a standard Arduino board with a battery will drain the cell very, very quickly. If want to run your project for long periods, have a look on this board: https://wisen.com.au/store/products/whisper-node-a...
It is designed to run on common AA batteries for longer periods and also counts with a wireless transceiver for long range communication... here it running on a CR2032: https://www.hackster.io/Talk2/temp-and-humidity-se...
6 years ago
mine works only if connected.why is it so?
6 years ago
This article shows how to run an Arduino clone from CR2032 for over a year:
https://www.hackster.io/Talk2/temp-and-humidity-se...
6 years ago
i am using 12v 8000mah battery for robowars
can i connect it directly to arduino?
6 years ago
How shall i make it work
6 years ago
If this was a rocker with an led where would you wire the led in
6 years ago
Looks like that is turning into a real product: https://bitbucket.org/talk2/whisper-node-avr/overview
7 years ago
The chip is rated at max 5.5V, I dont know if the Vin passes through regulator. are you about this?
Reply 7 years ago
ok so googling says
If you use the VIN pin, you bypass the diode, but you still have the dropout voltage of the regulator,
But regulator will eat your battery