I have a 2017 as well and there is a solid draw on the batteries even when the battery is disconnected via the interior switch. The culprits are the propane detector and the inverter which is always in standby mode waiting for you to press the "on" button. These 2 items bypass the battery disconnect switch and have a steady draw of close to 0.4amps (thereabouts) combined. 0.4 amps x 24 hours x 14 days = 134.4 amp hours = two completely dead flat group 24 interstate batteries.
When you store your trailer (just dropped mine off tonight) it's essential that you manually disconnect both negative leads on the batteries. One is an automotive clamp (main 12v
supply to the trailer) and the other is a ring terminal on the other battery terminal (feeds the inverter).
Remove these to completely isolate the batteries and eliminate draw while in storage. You must remove both.
Next week I'm installing a marine grade battery disconnect switch in the battery box and that will avoid having to physically remove wires to properly disconnect the batteries every time.
Here is the one I have installed on my other airstream.... I can choose inverter, inverter+main 12v
, main 12v
or all off.