I see a lot of "Old RVers Tails" here in the forums
The bit about keeping the AUX switch OFF when plugged in due to over charging....
Well long long time ago.. There were some very bad converter/chargers one of which was the Magnatek 6300.. These used big heavy feroresnate transformers (you need not know what that means) and were designed for 110 or 115 volts. Well the standard voltage has gone up since I was in school from 110 to 120 so this means the 6300 ran "Hot" (overcharged) also though the charger was only a few amps (The converter usually was around 30 amps but the charger less than 5) it had no clue as to when to stop.. So it overcharged.
Have not made any of those in years. The company was bought out and the new owners scrapped that line they make a much better one with decent regulation and a switching converter Smaller. Cleaner, Lighter and more efficient.