I ran the dockside charger
, and solar
array... (even wind
at one point), directly to the "house bank" alone, and the combiner is between the house bank and engine
cranking battery. This way my "spill over charge", which I have the least control over, goes to my much less expensive battery. (the engine battery). Since the engine battery is mostly full all of the time, and my self regulating alternator maintains over 14v when running, having the engine battery floated at 14.2 all day when motoring and the batteries therefore combined, seemed a bit excessive, so I put a switch on the blue Sea Combiner to disable the combine function when I choose to. (This is described in the unit's instruction book).
Now I crank the engine and after an hour of running, switch out the combiner, disconnecting the charge from the now, well charged engine battery.
In reality this extra precaution may not be an issue, as I have forgotten to switch them out before, leaving the combiner on, and my little $69 engine battery seams to last about 3 years, no matter what.
Having all charge sources go to the house bank only, and letting the combiner take care of the engine battery, is a very simple way to wire ones system, and has been successful for us for 15 years.