ADS1115

[oscgonfer]

Values close to GND overflow. See: adafruit/Adafruit_ADS1X15#97

[oscgonfer]

This will not be solved at the adafruit library level:

This might just be an unfortunate reality of the ADS1115. Found an old thread in TI's support forums:
https://e2e.ti.com/support/data-converters-group/data-converters/f/data-converters-forum/106949/question-about-ads1115-zero-piont-accuracy
with the comment:

One source of error that may be dominant when measuring voltages very close to 0V is the offset error.

adafruit/Adafruit_ADS1X15#97 (comment)

Still to investigate if we can do something ourselves.