Measuring Battery - Adafruit ESP32-S3 Manual

It's fine for, say, powering an ESP8266 WiFi chip or XBee radio though, since the
current draw is 'spikey' & sporadic.

Measuring Battery

If you're running off of a battery, chances are you wanna know what the voltage is at!
That way you can tell when the battery needs recharging. LiPoly batteries are 'maxed
out' at 4.2V and stick around 3.7V for much of the battery life, then slowly sink down
to 3.2V or so before the protection circuitry cuts it off. By measuring the voltage you
can quickly tell when you're heading below 3.7V.
On the ESP32-S3 only, there is a problem with the I2C implementation in
CircuitPython that causes the LC709203F to be unreadable. This issue is being
tracked at https://github.com/adafruit/circuitpython/issues/6311.
This board includes an MAX17048 Battery Monitor OR an LC709203F Battery Monitor
that reports the voltage and charge percent over I2C. (You will not have both.)
The MAX17048 battery monitor is available over I2C on address 0x36.
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