1. A boiling battery smells like that.
2. Your converter could be bad and boiling battery. Check the convertor.
3. Propane leak.
If a knob was bumped into the on position on the stove, propane can be coming from there.
Propane seeks a low level and the propane from the stove will find it's way into the adjoining kitchen sink and 'not' the floor which is why detector is not going off. Don't ask me how I know this one that almost killed me.
Open all the windows and get out of the RV until you find out where the smell is coming from and what it is.