I just read a thread on another forum about a beeping Schwintek controller....sounds just like you are describing.
He even unplugged it a took it off the wall, and it was still beeping.
After 2 pages of back and forths from members trying to help. It turns out it was the Ground Control beeping.
Iíve never heard of the slide control beeping, but if it truly is, then you should call Lipperts tech line. They have always been more than helpful when I have needed to call them.
And to make disconnecting your battery a lot easier, consider replacing that useless self resetting breaker that Jayco installed with one of these (or a cheaper version)