Dual Battery Set-Up

[Ghost Crab]

Just bought an 1984 Elite 32 and want to replace the batteries. The boat has a battery switch with two identical batteries. Everything seems to get power whether I'm switched to battery #1 or #2, or both, so I'm draining both batteries anytime I'm using anything. I've purchased a "starting" battery to start the engine which I want to be #1 and a "house" deep-cycle battery, which I want to be #2. But if I just connect those new batteries as the current ones are, I'm guessing I'll still be draining both batteries when I'm using my accessories under sail. I'm not sure if I there's an isolater in the battery switch. Just learning about all this stuff and not sure how to proceed to make the system work the way I want to. Any advice would be appreciated.

[Boomp]

Likely there is a switch near the battery. I use one for a main battery and keep the other as reserve. But there are a lot better systems to be learned about here.

[FSMike]

Ghost Crab -
Your system should be fed by whichever battery(s) is selected. If you disconnect battery #1 at its terminal and put the switch to #1, then you should have no current. Same for #2. If not, something is hooked up incorrectly.
When all is connected you should have power regardless of where the selector switch is turned if all is correct. Except, of course, when the selector switch is turned to off. Your switch does have an off position I hope?

[Starbuck]

I think Ghost Grab is asking for the easiest way to put in a house battery and a starting battery on separate circuits (I'm sure he'll discover they are separate when he performs FSMike's simple test), and have it work. But GG, please correct me if I'm presuming wrongly.

I get the idea he doesn't really want to upgrade a bunch of equipment, and isn't electrically inclined, and will be happy if he can avoid doing much more than just swapping out the batteries, hook them up intelligently, and have a simple protocol for using the system as is.

I think I know a few things he will need to know:

1. whether the alternator is wired through the battery switch, or directly to one battery.
2. whether or not the battery switch position can be changed between the 1-2-Both positions without losing contact and potentially damaging the alternator.
3. depending on the answer to #2, can that switch be used to to start the boat and keep both batteries charged.
4. depending on the answer to #3, does he need to purchase some kind of battery combiner or EchoCharge device?

Maybe if someone can talk him out of the starting battery idea, and just tell him how to use the 1-2-Both battery switch to do everything with two fresh deep-cycles, he'll be happiest.

I mean, he may just want to day sail.