Hi old dutchman, and welcome to the RVForum. Congratulations on your new-to-you RV! Most charging systems won't charge the house-batteries if the disconnect switch is off (in disconnect mode) so if you want to charge the batteries, leave the switch on. Your converter (the device that charges the batteries) is probably an older two-stage charger. If the RV is plugged in to shore-power all the time, two-stage chargers will often over-charge (boil) the batteries, so you should monitor the condition of your batteries closely to prevent that from happening.
A better solution is to invest in a newer three-stage charger. They're far better at sensing a battery's condtion and at reducing the charger's voltage to prevent over-charging. Really helps save batteries. Since the RV is new to you, I'd also recommend that you look at the date codes on your tires. If they are 7 or 8 years old, you should consider replacing them soon - no matter how good they may look, or how few miles they may have on them.
Kev
