I have an esp32cam that I've programmed and powered via an FTDI connected to a computer's USB. Now that this stage is over, I'd like to run it portably, using some sort of battery.

The esp32cam has a 5V input (also a 3.3V input which word is should be avoided because it causes brownout). I'm wondering if it's possible to power it (for a short period) using a 7.3V, 9V or 12.3V battery. All the datasheets I've seen seem to specify the input range is 5V, but, for the esp32 (non-cam version), unregulated 5V-12V seems to permissible. Is this true for the esp32cam? Also, what is the right way to search for this?

  • I'm researching the same topic. Could you please share any links about why 3.3V should be avoided?
    – kjam
    Commented May 3, 2021 at 9:26

1 Answer 1


The official ESP32-CAM has a AMS1117 voltage regulator that creates the 3.3V for the ESP.

The AMS1117 has an Absolute Maximum Input Voltage of 15V. It has a Dropout Voltage of 1.1-1.3V.

So you should stay above 4.6V to be on the safe side.

Since it's a linear voltage regulator, using a higher voltage battery has no advantage, as the "excess voltage" is converted to heat. It could even damage the regulator if too much heat is created.

You should pick the battery with the lowest voltage that still produces 4.6V when almost empty. So you could use the 7.3V battery you indicated. I'm assuming this is a 2-cell Li-ion battery, that has a voltage of 8.4V when full, and around 6V when empty. Which nicely fits your requirements.

  • This is awesome, thanks! I wish I knew how to find out these things on my own, but am not there yet. For example, how could I find it's an AMS1117?
    – Ami Tavory
    Commented Sep 5, 2020 at 14:58
  • 1
    Check schematics, and lookup datasheets for parts. Look through the entire datasheet. You'll see a lot of things you don't understand. Don't worry about that. In time you'll start seeing connections; know what things mean; know which parts are important, and which aren't. Some parts of datasheets I still don't (fully) understand, so don't beat yourself up. Learn Ohms law, and try to apply it everywhere. I found that electronics has quite a steep learning curve (coming from software development). So it may feel a bit overwhelming at first. Best of luck.
    – Gerben
    Commented Sep 5, 2020 at 15:12
  • What if I connect 5V to the 3.3V terminal of the ESP32CAM? Commented Jun 8 at 14:40

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