Thank you for your question! It makes sense that a lot of tech could drain your battery, but the car’s engine helps prevent this from being the case. When a car is running, the engine generates electricity to charge the car’s battery and run your electrical outputs like the AC and the radio.
The voltage regulator in your vehicle measures the charge of your battery, so when the battery is low, the running engine will send voltage back to the battery to sustain its charge.
As long as your battery and engine are maintained regularly, you should have no problem hooking up TV screens for the road trip.