Walt wrote:
I like Jim R's set-up, in theory. My bro-in-law had the same, but after a few years of removing, and hooking back up, he got a few things crossed, and didn't work quite right. I eventually went through, and landed all the smaller wires to the proper cables, and labeled. Just my recommendation to do so if you head down that road. The thing I did not like with the set up was the relay that closed to charge that batt. It was "on" even while starting, so potentially draining the cranking batt while cranking. I may eventually do the same general set-up with one deep cycle soley for the helm, lights and stereo; then have the two starting batts (w/ switch) to the starter, and bilge pump. I would also put in another disconnect so I could cross-connect in an emergency to use the stereo batt as a starter.
There are many charging relays out there - I use the Blue Sea Systems "Add a Battery" system which has a switch and an ACR or Automatic Charging relay.
http://bluesea.com/category/1/productline/overview/329This system can be configured in many different ways, and does include the provision for keping the batteries isolated during start up. The switch is basic On (isolated, but both batteries charge when a charging source is present), Off (both batteries off), and Both (where both batteries are combined). I've enjoyed mine a lot - as close as I could find to 'set and forget'. The only modifications I've made was to run an LED to the helm to be able to tell when both batteries are charging, and a switch to disable the ACR. The switch was a necessary addition when I added an on-board dual bank charging system - the ACR must be switched off so that the smart charger senses individual banks.
I do agree with labeling the wires that go to the various battery terminals. I added colored electrical tape to form a color band about three inches back from each lead. Green for starting system, yellow for house systems. Each battery has obvious tape stripes on it as well - I figure that I know where everything goes, but wanted to avoid a situation where a dealer or repair tech might get confused.