Thank you both for your tips! Please excuse the novice question, but what is the difference between the open circuit and short circuit voltage for the Peltier module? When I connected the Peltier between Vin(-) and ground, I did not get any readings - current and voltage both hovered at around 0. It was only when I connected the Peltier between Vin(+) and Vin(-) that I got any readings - the shunt voltage and current behave as I'd expect (i.e. increase with an increased delta T between the plates). The bus voltage and total voltages stayed at around 1V (why 1V by the way? Is that the power draw from the INA219?).
Basically what I need to know is how much voltage and current is generated by the Peltier module, so that I can use it to potentially power something else. What would be more accurate to measure in this case, the open circuit or short circuit voltage?
Thank you for your continued help, I really appreciate the time you take to answer my questions.