I think I have read this thread from top to bottom but I don't know what you're referring to with "that setting". Is like reading a mystery novel only to find the last page missing. "And the murderer is...." Put me out of my misery!
Haha.. it's the AUX BATTERY SAVER+ option in the settings. It was checked by default. unchecking the option seems to have stopped the alarm.
I have had the Aux Battery Saver on since day 1 with no alarm, and it does a wonderful job of charging the 12V battery, usually 14.4 V to 13.2V