Using 2AA Batteries for Nano

Hi guys, for christmas i printed a statue and painted it for my parents. I want to put in a arduino nano with 1 LED and a light sensor. Basically, when its dark, the LED shines.

So now i want to give my parents the possibility that they can use batteries to power it. I bought a 2AA Battery Case, but putting these on the vin and ground pin dont give enough Volt. The LED on the Arduino Nano isnt bright, which tells me its not enough power. So i need 5V, thats why I bought this dc-dc converter to convert the 2 AA batteries to 5V. but whenever I use this, the LEDs on the Nano dont even power on. I tried all 5 of those converters to make sure i dont use a broken one. Can messure curents because I dont have such a current gauge yet. What am I missing?
Edit: Using the converter both ways, so battery in VOut+- and Nano in VIn+- and other way around doesnt change a thing.

How do you know what you have the output voltage set to ?

Turn up the converter. There's a voltage drop on VIN so 5V through that pin won't power on the Arduino. Try 7 volts.

Without a voltmeter, how do you know that the DC-DC converters are outputting 5V? You will likely need to adjust the converters to output 5V and connect the converter to the 5V pin of the Nano.

after turning up the voltage the plastic of the battery case melts, because I looks like I do a short curcuit or so. However this shouldnt happen in my understanding, because i dont have a short curcuit.

  1. Take the batteries out of the case and verify nothing is wrong.
  2. Plug the Arduino into USB to make sure it's not dead.
  3. Test your voltage converter for shorts with a DMM.
  4. Test the output voltage of the voltage converter with a DMM.

Why did you pick a two cell case? A three cell case will provide 4.5 V which will directly operate the Nano perfectly well. That would solve all your problems. :+1:

Never use "Vin" for a real project. You power the Arduino via the "5V" pin.

A Nano includes the USB interface chip which wastes batter power since when using batteries, you are not needing the USB interface. A Pro Mini is more appropriate, you just need a USB interface adapter to program it.

But what is the purpose of the Arduino anyway? You only refer to the LED shining when it is dark. You clearly do not need a microprocessor for that.

Better yet, a 3.3V 8MHz Pro Mini, which would run fine on two AAs, at least for a while (at the Vcc pin). Three AAs, and it would run a long time if the LED isn't too bright.

The original problem I think was trying to run a Nano from batteries connected to Vin. Should be connected to the 5V pin. But for a Nano, it really should be three AAs.

Firstly what current does your project need? "1 LED" could be just a little one, or a massive 3A Luxeon star!

The MT3608 used in that boost converter can handle 2A, but these cheap plastic battery cases cannot - which is why it melted and may be why its not working.

You have to adjust the output voltage of the converter before connecting it or you risk burning up your Nano.

I'd also note that sometimes cheap products on Amazon or eBay are below spec or dodgy, I'd check its actually working with just the LED as load first.

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