This maybe is not a Corvette question but I know you geniuses know the answer !! My AGM battery has a 70AH rating. My cooler draws 40W DC. If my calks are correct I can only run the cooler 20 hours before the battery will be depleted? I=P/E. (40/12-3.4A) 70/20 = 3.4A Am I correct? If this is true, I'll be taking the cooler into the motel rather than leaving it plugged into the Vette overnight.