I have done this; the converter will supply 12V power to the devices that need the 12V. Check wiring to make sure the converter output still has a positive/negative path to the DC breaker panel.
Make sure you do not run large current systems (such as slides). The converter may be overloaded depending on the size of your converter/size of load.
Also make sure your inverter is shut off as well, as they usually draw straight from batteries.
EDIT: If you have a combination inverter/charger it might be a bit trickier....
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