Gary:
You likely have the Xantrex "Freedom" inverter/charger, with a panel above the driver to tell you what it is doing, as I have in my 1998 Contessa. Note the red lights on the display. Whether the inverter switch is on or not, when you are plugged into shore power, or the generator is on, you will see the "charge" light on. You will also see the amps measure lighted, so will know how much charging is being done. When you are not plugged in or generating and these lights are off, you may want to switch on the "inverter" and will again see the amps measure lighted, which will show you how much power is being sucked from your house batteries. Know that without any load whatsoever, the inverter itself will suck your batteries down quite quickly, so be careful to use it only when you need to. If you are mobile, your alternator will easily supply all your inverter will consume, so you don't need to worry about having the inverter on while you drive. Just be careful when you are dry camping, to keep the inverter off at all times that it isn't needed.