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I am a newbie to Arduino, so please bear with me. I am trying to figure out how to power an Arduino Nano with a LiPo battery. I want to use a 3.7v if possible, as my project needs to be lightweight. There are two possibilities I know could work:

-Taking a USB to Mini-B USB, cutting off the normal USB end, and soldering a connector (based on the battery I use) to that end. I would then plug the Mini-B USB into the Nano, giving it power.

-Using the 5v and Ground pins.

I would prefer to use the USB cable solution, however the 5v/Ground or any other solution is perfectly usable.

Also, would 3.7v be enough to power the Nano, two Infrared LEDS (Launch and Receiver), and a 7-segment LED display. I also have a button. Thanks, saddlepiggy!

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2 Answers 2

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In short: not reliably. The Arduino Nano expects either a 5V regulated supply or a 6-20V unregulated supply (https://www.arduino.cc/en/Main/ArduinoBoardNano). Even if you plugged it in and it worked initially, the battery voltage will decrease gradually as it discharges (LiPo cells can drop as low as ~3.2V), making it more and more unreliable. You'd technically be overclocking the processor, since the Nano runs at 16 MHz and the datasheet for the microcontroller requires at least a 4.5V supply to run above 10 MHz.

A safer solution would be to use a 2S LiPo battery (~7.4V), which would be plenty to supply the regulated input pin (VIN). On the other hand, if you're set on using a 3.7V LiPo, other Arduino boards (like certain versions of the Pro Mini) run at 3.3V.

As for your second question, 3.7V is plenty to power a few LEDs so long as they are connected in parallel (or to separate pins). The only thing you need to be aware of is current draw--more current means shorter battery life. For example, if your circuit draws 100 mA total from the battery, and your battery is specified at 500 mAh, you will get approximately (500 / 100) = 5 hours of battery life.

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  • You could set the fuses so that it runs on the internal 8Mhz clock. I'm not sure if powering the chip with 7.4V would do any good, since it's rated 5.5V (unless you use the regulater input).
    – aaa
    Commented Apr 7, 2016 at 8:23
  • So just to clarify, if I use a 7.4v LiPo,then I can hack the USB cable right? Or if I don't do that, could I use an alternate battery, like a AA pack or something?
    – saddlepiggy
    Commented Apr 7, 2016 at 14:42
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Late to the convo but quick comment in case anyone else reads this thread still. Arduino uses a linear regulator on Vin. In that case the “extra” voltage gets wasted. You’d get a much more efficient battery use by using a buck or boost circuit to provide it the correct 5V on the 5V pin (or usb) rather than feeding a 2S LiPo into Vin. It would work both ways but you’d get noticeably longer run time with a switching power converter.

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