All submarines are limited solely by the amount of food onboard. Toward the end of a deployment, the meals get interesting (chili mac with a side of canned beets, for example). The longest that I've been submerged was about four months, followed by two quick port visits, followed by two months at sea.
A smart TV, sometimes referred to as connected TV or hybrid TV, is a television set or set-top box with integrated Internet and interactive Web 2.0 features. Smart TV is a technological convergence between computers and flatscreen television sets and set-top boxes.
Any TV with an AC to DC power brick will have the Input and Output voltages listed on the brick. So there is no need to go to the store and test. Most smaller LCD TV's would use some sort of power brick. As far as Smart TV's are concerned, what do you mean? Internet enabled for apps like Netflix?