18650 Batteries for ESP32

[au_nel]

Hi guys,

This is my first time doing a project with ESP32 and I really don't know what appropriate batteries/setup to use..

I use ESP32 DevKitC Nodemcu. I have three sensors connected to it: DHT22, MQ-2, and MQ-7.

Are two 18650 batteries in series enough to run it? Or do I need to step the 3.0V - 3.7V output of the series batteries to 5V??

-Nelle

[ESP_Minatel]

Hi,

First of all, welcome to the ESP32 world!

About the battery, it will depend on the efficiency you are looking for. Usually using a single cell battery with a booster to step up to 5V with 1S charging circuit, is the easiest solution but not the perfect for energy efficiency.

For the batteries in series, you will need a 2S charging circuit and the LDO will heat (loose energy) a little bit more.

The ESP32-DevKitC is not the best solution for energy efficiency. It was designed for a generic purpose using a LDO with a dropout about 1V. This makes the dev kit not perfect for using a single cell battery on the 5V input pin, but it's possible.

Just a reminder, the ESP32 will die or will be damaged if you power with more than 3.6V directly. Do not connect 18650 battery directly on the 3V3 pin.

[username]

Sounds like you might want something like this that does it all for you.
https://www.sparkfun.com/products/18018

[au_nel]

Firstly, thanks for replying! It's my first time using this platform and I was waiting for so long for the notification button to change but it didn't and I thought no one replied to me (I realized just now how stupid this was )

I tried powering the ESP32 with two lithium AA batteries in series through both the 5V and 3V (which I just learned that I shouldn't have done. Oops.) pins directly and both did not work. This ESP32 was supposed to send the sensors' values to another ESP32 using ESP-NOW. I have been powering my ESP32 using my laptop with all the sensors tapped to the 5V pin and it was working perfectly. When I tried the series lithium AA batteries, the sensors lit up the same way it does when I was using my laptop (which I assumed means that it gets enough voltage?) but the sensors' values weren't being sent to the other ESP32.

I haven't tried using any charging circuit and its going to be the first time using one (so sorry if I'm annoying you with my cluelessness) so I guess I'll have to play with it a bit.

For the ESP32 Thing Plus C, unfortunately, I already ordered all the ESP32s I need for this project so I just have to make do with what I have..