The generator does the same thing plugging in to shore power does.
Supplies 120VAC to the unit. That means that it powers the converter which charges the batteries and provides a supply of 12V power.
Units without transfer switches have to plug their shore power cord into the generator.
However, If the convertor is bad I think it will not supply any 12V power, The engine alternator will supply a little 12V power regardless of the convertor status (I think).
Life is a journey, not a destination.
2005 Georgetown 359ts
Bill & Virginia, Kentucky
Nights camped in 2011...78 , 2012...73,
Nights camped in 2013...123, 2014 ...101