HTCC-AB02 ADC internal reference not working


I have a HTCC-AB02 and on ADC2 I have a lin. potentiometer.
If I power it via USB everything is fine, but if I power it over battery, the ADC1 reading goes down with the voltage of my battery. According to this whole thread this should not happen, since the internal reference of 1.1V is already on and we don’t have to turn it on manually.
So either it is not truned on, so I’m wondering how to do that, since analogReference(INTERNAL) is not working ?
Or it is turned on and something else is wrong.
I would highly appreciate some help :slight_smile:

hi Mel, dear all,
is there any useful hint in this matter? Maybe another thread I am missing? - The ADC readings of my Heltec Wireless Stick (V2) are so inaccurate the they are virtually useless. To the point:
1st: Is there an internal ADC reference Voltage in the Heltec Wireless stick? How do I activate it (code snippet is appreciated)?
2nd: Is there an input for an external ADC reference Voltage in the Wireless Stick (similar to what the Arduino Nano has)
3rd: If NO for 1st and 2nd, does the Wireless Stick V3 have it?

Any hints are welcome! Thank you!