Originally Posted by GregM

We are newbies but we understand it to depend on various factors such as the Battery size and TV power usage.

Our 12v TV runs at about 4 amps, and our leisure battery is 113 ah, which in theory means we could watch the TV for 28 hours. This assumes that you have no other 12 volt appliances running.

In Reality we found that our leisure battery can last about 3 days, that is with the TV on for a couple of hours each night, lights and kids charging DS's etc. We have just added a 2nd leisure battery and plan to purchase a solar panel next so we can manage for long trips away.