Before heading out on your first adventure in your brand new (or new to you) Airstream, it’s important to know how your trailer is powered. For all years I’ve come across, you’ll have two power sources which are the battery (12 volt) and shore power (110 volt).
The 12 volt battery will supply power to very important items such as all lighting and your water pump when off grid. Even if you plan to be connected to 110 volt power, the battery will still supply power to these items and be charged by the 110 volt line through the inverter. If your unfamiliar with what the inverter does, it will take shore power and convert it to 12 volt power which will safely charge the battery. In turn the battery will power your lights and water pump. Side note: you only need the water pump when you aren’t connected to a fresh water source and are instead pumping water from your fresh water tank.
Your 110 volt power (shore power) is provided by hooking the rear 30 or 50 amp power line to a power pole. This power source will power all remaining items such as anything plugged into a wall outlet, electric water heater, air conditioner, and power inverter, which in turn charges the battery. For many of you, the inverter can remain on as it will analyze the battery level and determine how much power is needed to be fully charged. If you have a vintage unit with the original inverter, you must only activate the inverter as the battery gets low, otherwise you’d fry the battery (not that I’ve ever done that).