Many inverters are also your coach converter.
It may be/should be the 120v to 12v converter you're hearing/seeing and not the 12v to 120v inverter. They reside in the same housing.
And the inverter side is always a little bit 'on' so it can sense when the shore power drops voltage or is disconnected, automatically Taking up shore power slack.
Mine is also the battery charger.
(I hope I have this correct. I'm pretty sure this is how a xantrex 3012 works)
Telling us what brand and model of your inverter would go a LONG way toward getting a more correct answer.
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