Batteries
Difficult to explain, but I give it a try
You have 2 batteries. The engine
battery is for ignition, gives at 100 %: 12,7 V. Able to give a strong current for a short time (starting). But: if down under 12,4V it could be ready for the scrap !
Your leisure batteries are slow unloading (light inside, TV...) They could go down to 40% (12V) without damage.
When you are driving the (engine)generator fills up first the engine
battery and then the leisure
battery. Between them is a one-way diode (engine batt>leisure) (avoiding one
battery is sucking off the other).
When you hook-up: the built-in transfo is only feeding the leisure
battery
not the engine
battery (wrong one-way).
So it has no sense to hook-up for weeks, you're only feeding the leisure
battery. And this-one ia allready charging up after about a 20 min drive.
If you are idle for some weeks you could aply a (drip)charger to give your startbattery a better rendement.
just buy one of these cheap Volt-meters from A..I to check the voltage.
Give you the %
100%: 12,7V
90%:12,6V
80%:12,5V
70%:12,4V
60%:13,3V (here begins the alarm-level for your engine
battery)
50%:12,2V
40%:12,1V
Hope this gives a little bit light in the darknes
Groetjes