My preference is a separator, since it works both way and can be manually overridden.
First, as you know the engine powers the alternator which charges the starter batteries- this you already have:
Code:
Engine -> Alternator -> [Starter Batt]
In the same vein a charge controller using what is 120v* in the US, or a solar panel using the sun's energy will charge the house battery or batteries:
Code:
<-- Charge Cont <- Shore Power
[House Battery] <- Solar Controller <- Solar Panel <- Sun
The separator joins the two sets of batteries when the voltage indicates a complete charge on one (I'll use 14v), so when the starter battery is above 14v, it is connected with the house battery and they essentially become one. If the house battery is not fully charged, the "one" battery will need a charge and the alternator will continue to charge.
Code:
[Starter Batt] -> Separator [House Battery]
( >14v )-------->
Ditto the house battery, when it is above 14v the separator connects and again both become one and charging continues if needed:
Code:
[Starter Batt] Separator <- [House Battery]
<-------( >14v )
So here is the whole thing put together:
Code:
<-- Charge Cont <- Shore Power
Engine -> Alternator -> [Starter Batt] -> Separator <- [House Battery] <- Solar Cont <- Solar Panel
<-------( >14v )-------->
You hook everything you can to the house battery, so that the fridge, fans, lights and whatever else you'll use to camp won't kill the starter batteries. If the starter batteries are down, you can force the separator together and essentially give yourself a jump start. The main benefit to the separator is that it charges both ways, so both sides get topped off regardless of your power source.
I don't think Solar adds any complexity, because once through any controller (which includes the alternator) the charge looks the same to the batteries. You could put all three on one side, or hook the alternator to the house, etc. Generally the starter battery/alternator system is sufficient for the starter side, so it makes sense to put any additional charges to the house side where you'll also be draining from when camped.
*I assume that all this translates from whatever European standard (230v now?) to a 12v auto system with locally available chargers- likewise if you run an inverter it will be putting out 230v into locally standard wall outlets.
Linear Mode
