House Batteries Dead

Offsite storage is a PITA. When we stored our rig at our house it was easy to keep it plugged in and keep the batts charged. But if there is no power supply, despite the disconnect turned off, they will still drain. The only way I have found to prevent it is to physically disconnect the terminals. I have no idea why the disconnect still allows for a small drain, but it does. Someone could probably explain it, but it doesn't really matter. Disconnect allows for "most" things not drawing power and will work for short periods like a week or so until they can be replenished. But for long periods, physically disconnecting them is the only way I've found to keep it from happening.