If it's continuously plugged in you should never need to use the disconnect. If it's turned to off & plugged in the batteries will not charge.
The best way to totally disconnect the batteries is disconnect the negative cable. The factory disconnect does not totally disconnect all items such as LP/CO detector, electric slide motors & possibly other items that will drain the batteries in just a few days.
Danny & Linda
Sold my '13 Redwood 36FB
Currently rv & truckless