How to connect a LiFePO4 battery directly to an esp32?
No. Absolutely not.
A LiFePO4 battery is 4.2V when fully charged. The absolute maximum voltage of an ESP32 is 3.6V.
You will kill the ESP32.
Instead you need to have a voltage regulator with a very low dropout. Ideally a switching (&quot;buck&quot;) regulator with a zero-dropout &quot;pass&quot; mode to give the maximum life from your battery.
Even better is a &quot;buck/boost&quot; battery regulator that will boost the voltage up to a stable 3.3V once the battery voltage drops too low.
If all this is beyond you then you're better off using a powerbank to do the regulation to 5V for you then convert that back down to 3.3V with a simple buck regulator.