As I said , I can only go on what I actually works for me in real life situation...and it works the way I described it.
If the 2nd battery wasn't being fully charged it would not be at 12.8v.... while the main battery shows 12.5v...... And the top 12v socket IS seperate from the main battery, while the cigarette lighter is connected to the main battery.
If the 2nd battery wasn't being fully charged it would not be at 12.8v.... while the main battery shows 12.5v...... And the top 12v socket IS seperate from the main battery, while the cigarette lighter is connected to the main battery.