ADC accuracy depending on AREF?

Hi for an arduino project powered by batteries which option gives better accuracy (if there are differencies) : 1. Using the internal AREF? 2. Using the 3,3V from the arduino regulator?

Harry

for an arduino project powered by batteries which option gives better accuracy (if there are differencies) : 1. Using the internal AREF? 2. Using the 3,3V from the arduino regulator?

Both should work as well as both are regulated and will not change as battery voltage drops. However the same is true if you are using battery through the external power connector (7.5-12vdc) input as that then goes to a on board 5vdc regulator that also will not lower as the battery voltage lowers.

Lefty

Thank you very much Lefty