[Carl n Susan]

The disconnect switch with the red key in the convenience center does *NOT* disconnect all the 12V. There are several parasitic 12V devices which are exempt and will drain your batteries. The best solution is to disconnect the negative cable on your batteries. This will ensure they are not drained in storage.

I have no idea how your solar is wired and what it can do.

The beeping sound might be from your propane detector due to low battery voltage. You will have to get the slides open and identify exactly where the beeps are coming from.

As for the batteries, you might be able to charge them up. They may not be as strong as before, but should work to get the slides out.