Nano 33 BLE external power supply


I'd like to know if I would be able to power a Nano BLE 33 with a 3.7V 1000mA Li-Po battery? The datasheet says the operating voltage is 3.3 V

But the note below it says that VIN should be a minimum of 4.5V. Please advice a valid power source for a Nano BLE 33 . Would two 18650 3.7V batteries in series be a better option?

Basically no. When using an external power supply make sure it can supply a minimum of 4.5v and a maximum of 5.5v . The closer the voltage stays to 5v the better. Two batteries would be my preference with sepic converter.

Welcome to the forum.

The answer depends a little bit on what you want to achieve. If you do not care about power use a USB power adapter and connect your board via a USB cable. The same is true for USB power packs but you will have a time limit depended on the size of the pack maybe a day or two for an average pack.

If you care about power and want to run the board as long as possible from a battery you need to first make sure the sketch uses as little power as possible. There where are few discussions in this sub forum (disabling LEDs, sleep modes ...). Have a look. Also check the BLE Sense sub forum.
Then you need a 3V power source and disable the onboard power regulator by cutting the bridge under the PCB (see FAQ in store link below) . Then you can power the system via the battery directly.

BLE was designed for 3V coin cells like the CR2030. That is enough to runs small sensors for many months e.g., heart rate monitors, cycling sensors, temperature sensors ...

Unfortunately, the battery you have has the wrong voltage and therefore will always require some voltage regulation which will burn more energy than using a 3V battery in the first place. But if you only need to run the app for a day or a few, you could try to build your own little regulator circuit and then bypass the onboard regulator. The onboard step-down converter has likely been chosen because of the large input voltage range. You can do better because you do not need that.
There are many options, I suggest you use a parametric search on DigiKey or another distributor.

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I also like to run the Nano 33 BLE Sense board with a Li-Po battery (3.7V). I plan to use an external LM3671 regulator board made by Adafruit and bypass the onboard regulator. The LM3671 is rated for 600 mA. I cannot find the maximum power (or current) rating of Nano 33 BLE sense board from the website. Do you think I can use this regulator?


What would happen if I use a 9V battery ? The input voltage limit is 21V

If it is in spec it should work, you can find that on the data sheet. Note with the 15 mA current requirement you will only get about 33 hours with nothing else connected.

I'm using a 9V on my project. No problem.

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