.. or resource about setting up a split-charge system.
especially how things wire in...
i currently have a regular set up where i have a power lead run up through the car to an amp which drives two subs..
however.. what i'm hoping to do is make a set up where i can add a removeable (i mean 10 mins work to switch) option which
contains a battery that is split-charged to power a fridge and a 12v rechargeable lantern/or lights on a extension etc...
i'm not overly bothered about a long duration.. what i really expect is to put drinks etc in fridge.. drive whereever (which would run fridge...) drink some after pitching tents..

? ?turn fridge off... . recharge some if i i drive the next day.. and turn the fridge on again once the edge is taken out of the day.. at a bare minimum thats what i'd like.. being able to? last arrival night, and the following night always 'on' would be awesome..
it would also i suspect be a good idea to precharge the other battery off the car, or run the car with it in running up to going away..
could even invest in one of these..
http://www.tgincar.com/osolarcharger.htm anyways.. i'm hoping i can do something with the existing amp power wire and a split charge set up.
surely you guys going to shows must have some experience of this?