I have a new Thunderbolt 386x12 that every time I put it in storage for even a week, it will draw the battery down to where it will not have enough power to raise the gear. I always turn off the disco...
The problem with this is in the terminology. The built in "Battery Disconnect" (n the control panel on my Fuzion) doesn't disconnect everything. You can install one as suggested by posters which disconnects everything from the batteries.