Picture of Powering Arduino with a Battery
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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).
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BoKKeR4 months ago

I want to know what kind of battery, notebook and how much I need to power the arduino for 2-3 days

you can run it for a year with lithium battery 1500mAh + sleep mode

Hey Narzan! Surely that wouldn't work for the Arduino Uno, due to the idle current draw of the regulator, USB module, etc? At least, that's what I've been reading. Or do you have a sleep library that can somehow shut those off?

It will work for Arduino UNO too ;)
remove all LEDs, Cut the line for the Convercor Serial USB, or put a a switch to turn it OFF, anyway I am used 1500mAh battery and it's work for a day without any problems, but without any other shields , you can find out some codes in Arduino playground library

JonatanG21 month ago

how long can you run the Arduino Uno with a 9V battery?

anunziante1 month ago
can I use a battery like the one I'm posting. 6cell 7.4V 1100mha
GalenW13 months ago

I am pretty sure 6 AA batteries in series will last longer than a single 9 volt

corradini GalenW12 months ago

I think you're right. In fact, I think so because *I'm* pretty sure that a 9v *is* 6 (small) 1.5 cells in series. (If you crack one open, you'll find 6 smaller versions - maybe "AAAA"? of that type of cell.) SO: if you put 6 AA's in series, you're making a larger version of a 9v. Hence more mAh.

ChristianE13 months ago

Hi: I am verifing the Vin method posted here using a 9V battery (200mA) marked with my digital multimeter as 8.9V, and it seems to be an issue:

-When the arduino UNO board is powered using the battery I get the chart from the left which is not even close to the expected values on out pins of 3.3V, 5V and an analog signal on pin 5

-When the arduino UNO is connected through USB I get the chart from the right in to 3.3V, 5V and a signal from an analog pin 5, which are right.

Is the arduino UNO board requiring more power that it can be supplied?

tclayton3 months ago

very new to arduino, thank you for this simple explanation and visual example.

davehartles694 months ago

alternatively buy a pp3 battery clip for ardiuno

JRV314 months ago

Is it all right with you if I add this instructable to my beginning Arduino collection?


Arduino4Me5 months ago

Can I use a 6A 250V AC toggle switch?

Also, it has 6 "pins" how would I go about wiring it up to the Arduino?

Sure. Use one center pin and one outside pin on the same side of the switch and wire it like the photo provided by the author above.

Okay, thanks!

Arduino4Me5 months ago

How would I do the same thing only with a Mega?

Arduino4Me5 months ago

Wow, thanks so much!

Extremely helpful!

Mawtees8 months ago

Can you use this with servos and no breadboard? (The servo goes into the 5v and ground pin)

Gelfling6 Mawtees6 months ago

You can, but only 1 servo! the +5V regulator on the board has very little amperage, and can either brown-out (too much draw) or even burn-out (over-draw) if pushing more than 1.. I tried this with a robot design, and it began chattering because the two drive servos were drawing too much. (browning out), and the arduino kept resetting.. I highly suggest using an external 5V regulator (a 7805) in parallel with the Vin, and not drawing from the +5V pin unless you're using it to power external TTL chips (Even then, still possible to have brown/burn out.) Simply wire the Vin to the input of the 7805, GND to GND, and wire the servo +V wires to the V-Out pin of the 7805. Someone had plans for soldering a parallel regulator onto the Arduino, which could handle the extra load, but you're also limited by the copper traces of the board.. Accidentally fried the Vin trace from the regulator, over to the Vin header pin, when the board fell and shorted on some metal pieces. Re-bridging PC board traces is not a fun task! Also, Very highly recommend against back-feeding the 7805's output to the +5V pin.. Some versions of the arduino, seem to fry the automatic switch circuit that switches from the USB +5V, and the regulator. (especially on the V3 Arduino's with the AT16U USB<-->Serial)

Mawtees8 months ago

Can you use this with servos and no breadboard? (The servo goes into the 5v and ground pin)

funky811 year ago

Hi, thanks for your info. One question, is it possible to monitor battery voltage ?

if it's possible, do you mind to show it?


djmelvinv funky8111 months ago
hi you can use two resistors as a voltage divider to go under the max 5v. then connect de pin between de resistors at an analog pin for example A0. Now you can map the analog value to you battery values. so 0-1024 mapped to 0-12 (when using a 12v battery).
amandaghassaei (author)  funky811 year ago

you can measure battery voltage with a voltmeter, is that what you mean?

Ahmedqatar1 year ago

Seem good but how long a battery may last??

arduino uno made a pop noise when i did this thankfully it still works
amandaghassaei (author)  thesonyman1011 year ago

be careful to get the connections right!

funky811 year ago

Hi, thanks for your info. One question, is it possible to monitor battery voltage ?

if it's possible, do you mind to show it?


ktitiz1 year ago
if you build gps or using something shield like lcd, you will get to 2 or more 9v battery,
mangopeach2 years ago
This is also a thing:
agupta522 years ago
Tried the same not working
Gelfling62 years ago
I've done similar, with a converted ATX supply, back-feeding +12V through the VCC pin. But, one word of warning, this still feeds back to the coaxial connector, then through the +5V regulator, and it's a thin trace on the bottom of the board. (all models from the Diecimila, to the present day Due and even the MEGAs,) I had to re-bridge this thin trace, when, powering a Duemilinove off the stock 9V battery pack, and a wire coming from the VCC pin, popped out of the breadboard, and touched a GND connection.. (Ironic, it was feeding a LM7805 regulator that was on the breadboard to power a couple of servos. guess what it touched? [o] )
myth212 years ago
hi i have one question...i have a buzzer that operates from 6-12v..and i put it on the arduino board that only produces 5v..and its working.. is it alright?wouldnt it damage my board??thanks
amandaghassaei (author)  myth212 years ago
use a multimeter to measure how much current the buzzer is drawing, if it is pulling close to 40 then maybe try using a transistor to source the current directly from your power supply. does that make sense?
A 9V to 2.1mm connector is less than $2.


Makes things far easier and way less complicated.
you can also take apart a used 9 volt and take the top piece with the connectors, solder wires to the back, solder those wires to a 2.1mm plug from an old power supply, and then cover the end with shrink tubing or epoxy. you just made one for free. I've already made a couple.
amandaghassaei (author)  bears03 years ago
cool, you should make a photo instructable and enter it in tips and tricks!
amandaghassaei (author)  JoshuaZimmerman3 years ago
it's not easier, now you need a plug and a snap battery connector and a switch. I like using the vin pin bc the barrel plug takes up a lot of space, if you want the arduino's usb port accessible to the outside you can't use the barrel plug, it's just too bulky.
Ahhh, see, now you're putting it into context. Like your box. That makes sense in your situation.

The way your write up is worded it just seems as if you've got your Arduino powered up by this method at all times for some odd reason. Which makes no sense and seems overly complicated.

Now that you've placed it in context with a larger project when you wish to keep the USB port flush with your case, everything falls into place.

Maybe you could go back into your write up and add a paragraph explaining WHY you've chosen to do this method and put in a picture of your box.
caitlinsdad3 years ago
There is the power supply jack at the end which takes a 2.1 mm barrel plug which makes a nicer connection.
I agree w/ you there, I prefer to keep all of my headers open for use.
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