Battery level sensing for ESP32

Thread Starter

trav333

Joined Mar 7, 2022
44
I want to sense the battery voltage of a 3.7 Li ion battery with ESP32

Should I run 3.3V to an Analog enabled GPIO to show when fully charged at 4.2V using a voltage divider from the battery voltage with values 27K and 100K. I also want to sense when the battery is low below 3.5V (module will switch off at 3.2V using buck boost IC.)

I just want to confirm I am on the right track. Thanks

I found another thread on this subject mods can delete if you like.
 
Last edited:

ericgibbs

Joined Jan 29, 2010
18,766
Hi trav333,
The 12 Bit ADC of the ESP32 has very poor linearity, to get exact reading you will have to correct the value in software.
I am currently working on a ESP32 using WiFi into my router to PC Web page.
For a 3.3V test voltage, the ADC reads 2.6V. !! [ I have tried 3 ESP32' all give the same error]
Changing the project to use an external ADC, I have some MCP3302/4 IC's

E
 

Thread Starter

trav333

Joined Mar 7, 2022
44
Hi Eric thank you great video and you gained a subscriber!

Accuracy is not that important in my application so I will have a play with the code to see if it is sufficient. I did see a comment on the video about how to accomplish that.

Thank you!
 
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