Colder the pelt gets, the less its resistance to power becomes, and thus you turn it more into what amounts to a short circuit. IE you are basically shorting out your power supply and turning the TEC into a heater. I am unsure how it will react to -20 how ever I am fairly sure you will not get what you expect.


the colder you make the hot side then the colder the cold side gets as it comes closer to it's theoretical delta T. My pelt's Delta T is -26c so if I cool the hot side with -20c water then all the pelt does is get even colder. This is as long as I can feed it 13.8 volts at 25a or so.
Albeit thats what one would intuitively think but that assumes A:100% efficiency and B: its resistance to power remains the same, how ever this is not the case.

Any case good luck and be interesting to see what happens, though you'd be much better off just ditching the pelt all together and running you coolant at a lower temp.

FYI Sterial your statement is so wrong in this field it is sad, Learn about what you're saying be for giving bad advice. Yes Philly you want slightly more alcohol then the lowest expected freeze point.