Everyone so far who answered were correct. But it might be helpful if I go into a little more detail. You have 2 electric systems in an RV. You have ac which is the same as the electricity in your house. The ac powers the microwave, air conditioner, and the electrical outlets you plug in the TV, hairdryer, etc. You also have a dc electric current (battery current) which powers the lights, and control boards for the furnace and refrigerator. When you plug into an electric power pedestal you get ac power. In addition, the ac power runs a converter-charger which converts the ac to dc (battery type) electricity. Thus, you can turn on the lights and run the control boards of the refer and furnace even if you disconnect the batteries. In addition, the charger part of the converter-charger will charge the batteries when your RV is plugged into an ac pedestal. I hope that answers any questions you might have about the ac and dc systems in your RV.
