Power an Arduino Nano externally

Thread Starter

SeanV123

Joined Nov 12, 2020
68
Hello,
For a certain project, I want to power an arduino nano externally and I am wondering what is the best way to do it. Could I connect a 9V battery to a micro USB and connect that straight to the nano?
I appreciate feedback and help with this!
 

Yaakov

Joined Jan 27, 2019
3,521
Hello,
For a certain project, I want to power an arduino nano externally and I am wondering what is the best way to do it. Could I connect a 9V battery to a micro USB and connect that straight to the nano?
I appreciate feedback and help with this!
Pin 17 on the diagram provided by [USER=73660]@ericgibbs[/USER] is the 3.3V input to the board. Connection a LiPo battery to this and GND (pin 29) will power the board well.

No, as @ericgibbs points out later in this thread, this is the output of the on board regulator, not an input! Don't connect voltages to that pin.

LiPo is still your best bet, but you will either have to put two cells in a series or use a (cheap, readily available boost converter) It can be recharged, and there are management boards for the purpose to make it even better.

You will need to connect it to pin 27, with the negative side to GND on pin 29.

9V batteries are among the very worst power sources. They are very low capacity and extremely expensive compared to other options.
 
Last edited:

Thread Starter

SeanV123

Joined Nov 12, 2020
68
You are completely correct, I had the wrong board in mind. Thanks for catching that Eric! I will edit my original response.
So to be clear, I would connect a LiPo battery (of which capacity?) to the 5V pin on the nano? And the negative of the battery to the GND pin?
 

MrSalts

Joined Apr 2, 2020
550
Vin allows 7-12VDC input to be regulated down to 5v that the board’s microcontroller can use. The output of the regulator connects to the same node on the circuitry as the USB 5v power input and the 5v pin auxiliary pin on the board. I don’t know what happens if you connect 7v or less to this pin but it is specified at 7 to 12VDC on ost Arduino boards
 

Thread Starter

SeanV123

Joined Nov 12, 2020
68
Vin allows 7-12VDC input to be regulated down to 5v that the board’s microcontroller can use. The output of the regulator connects to the same node on the circuitry as the USB 5v power input and the 5v pin auxiliary pin on the board. I don’t know what happens if you connect 7v or less to this pin but it is specified at 7 to 12VDC on ost Arduino boards
So if I connect a 9v source (for example) to the Vin pin on the arduino nano, it will work away with no issues because the 9v source is regulated to 5v? If so that is the answer I was looking for!
 

MrSalts

Joined Apr 2, 2020
550
Yes, 9v to the Vin is fine, I don’t understand why other members try to make things more complicated and less safe by instructing you to use LiPo batteries
Understand that a 9v battery won’t last long but it will definitely last some 5 to 20 hours (depending on what is connected to the arduino)
 

Thread Starter

SeanV123

Joined Nov 12, 2020
68
Yes
Yes, 9v to the Vin is fine, I don’t understand why other members try to make things more complicated and less safe by instructing you to use LiPo batteries
Understand that a 9v battery won’t last long but it will definitely last some 5 to 20 hours (depending on what is connected to the arduino)
Yes, I must look for some sort of battery with a larger capacity? any recommendations?
 

Yaakov

Joined Jan 27, 2019
3,521
Yes, 9v to the Vin is fine, I don’t understand why other members try to make things more complicated and less safe by instructing you to use LiPo batteries
Understand that a 9v battery won’t last long but it will definitely last some 5 to 20 hours (depending on what is connected to the arduino)
THe reason for suggeting LiPo is the inherent superiority in practical projects. The 9V battery is a terrible power source.

“Less safe” is a serious overstatement. Yes, it is “less safe” technically, but it is still very safe. Modern LiPo batteries and charging modules are easy and safe.

f you are using a 9V battery to test something, well, that’s OK. But if you need to power something by battery, in practice, the 9V is bad and learning to use the proper technology is worth the time.
 

Yaakov

Joined Jan 27, 2019
3,521
So if I connect a 9v source (for example) to the Vin pin on the arduino nano, it will work away with no issues because the 9v source is regulated to 5v? If so that is the answer I was looking for!
From the Arduino website:

Power
The Arduino Nano can be powered via the Mini-B USB connection, 6-20V unregulated external power supply (pin 30), or 5V regulated external power supply (pin 27). The power source is automatically selected to the highest voltage source.
 

djsfantasi

Joined Apr 11, 2010
7,842
From the Arduino website:

Power
The Arduino Nano can be powered via the Mini-B USB connection, 6-20V unregulated external power supply (pin 30), or 5V regulated external power supply (pin 27). The power source is automatically selected to the highest voltage source.
Just to be sure, you can only connect a 5V regulated power source to pin 27. A battery should NOT be connected here. Pin 27 connects to the output of the 5V regulator. Vin connects prior to the 5V regulator and thus can regulate the power from a battery.
 

Yaakov

Joined Jan 27, 2019
3,521
Just to be sure, you can only connect a 5V regulated power source to pin 27. A battery should NOT be connected here. Pin 27 connects to the output of the 5V regulator. Vin connects prior to the 5V regulator and thus can regulate the power from a battery.
Yes, I hope that was clear when I said there would need to be a boost converter involved, but I suppose to make it even more clear, if you put cells in a series to get a higher voltage, you will need a buck converter. There are so many boards designed to handle this for just such an application I would strongly encourage learning to use LiPo power sources with the appropriate power management modules over 9V batteries which are really garbage for modern applications.
 

Yaakov

Joined Jan 27, 2019
3,521
I think I need to write up a little primer on using LiPo power sources for Arduino and similar projects. It’s not hard, but for a neophyte there might be too many moving parts to pin down without help.

I think it is a worthwhile project to do.
 

Yaakov

Joined Jan 27, 2019
3,521
I didn't mention, but should, if you were willing to use the USB input then a single cell 18650 powerbank provides more capacity than a 9V battery, has charge circuitry built in, and is cheap. A short cable and the powerbank is a quick way to get a good power source if you don't have a high run time requirement nor a size constraint that prohibits it.

No special knowledge required, rechargeable, cheap, readily available, extremely superior to the obsolete 9V "transistor" battery which needs to find its final rest.
 

Thread Starter

SeanV123

Joined Nov 12, 2020
68
I didn't mention, but should, if you were willing to use the USB input then a single cell 18650 powerbank provides more capacity than a 9V battery, has charge circuitry built in, and is cheap. A short cable and the powerbank is a quick way to get a good power source if you don't have a high run time requirement nor a size constraint that prohibits it.

No special knowledge required, rechargeable, cheap, readily available, extremely superior to the obsolete 9V "transistor" battery which needs to find its final rest.
So I can power the arduino nano with a power bank via the micro usb port? That sounds great, lot less complicated than using the Vin pin. Not that it's not very complicated to begin with!
 
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