Arduino supply voltage

Hi There, new to this. This is my first project i have built. Can I run Arduino UNO on 12v ? have been running on 9v battery but goes through batteries fast. I have 800CCA 12v car battery that i use to power motors and steppers. Can i use this to power UNO as well?

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Hi Paul,

Welcome to the forums :slight_smile:

Short answer is yes - The Uno’s have an onboard voltage regulator that can accept anywhere from 7v-15v DC (20v max). To power an Uno from a volatge source more than 5v, you’ll need to connect via the DC Barrell Jack connector, or the V_in pin.

See here for more info:

You also might like to check out chapter 1.5 in our Arduino for Beginners Workshop:

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Thanks Oliver, that will make things a lot easier :+1:


Hey Paul,

By the way, if you want to provide power from a source other than a battery so you don’t have to worry about them dying you can always use a power source that matches the voltage and power output for your board. Also, generally, the boards don’t draw too much power without excess peripherals, so if your board is heating up significantly then you may want to check the amount of current that it’s drawing to make sure there are no issues with it.


I use a 12V 1.5A plug pack that came with a old USB disk drive. Plugs neatly into the Arduino.
Disk drive is no longer in use. The link by Bryce will give more than enough power for most projects.

you can add buck regulators if you want multiple voltages from one supply…!!!
just don’t exceed the total wattage from your supply output…!!!
the one Bryce posted above has a 60 watt total wattage output… !!

this is one of my supply units.