I have similar. 2.7V is as design for the onboard TP5410 chip. My problem is charging stopping too soon at <4.1V. Works best with genuine 18650s, avoid the widespread fakes.

To use ADC attenuation I need to buffer the pins with voltage dividers. To minimise battery power and use highest resistances what is the minimum input current for an ESP32 analog input pin?

Depends on compression ratio and level of detail in image, but for an order of magnitude; 10-30kB

Thanks

The ADC pin input voltage measurement can be attenuated, e.g 6db reduces it to around 2.2V according to
http://esp-idf.readthedocs.io/en/latest ... dc_atten_t

But is the pin still 3.3V tolerant?