Help with proper battery connections

[02hydrotherapy]

Last yr I purchased a 2002 Mariner 350 that has 4 batteries in it. When the boat arrived and looking in the engine room a worker at the dry dock noticed the batteries are all linked together and mentioned he had never seen this. I have been unable to separate the batteries using the aft cabin battery switch ( 1, both, 2 ) therefore my batteries are going dead while out for 2-3 days. They are wired in parallel series and I would like to hook them up correctly, individually.

If anyone can send me a picture and description of how their batteries are hooked up or a link I could go to for this info I would greatly appreciate it. And I'm assuming ea battery would then need to be connected to the on board charger? As of now there is just one wire connected to the batteries from the charger.

Thanks, Jerry

[mjk1040]

Can u post a picture? Are all 4 batteries 12 volt? Do u have a generator? Charger wire should have been attached to battery switch I believe originally.

[02hydrotherapy]

I don't have a picture and all four batteries are 12 volt. In the owners manual it states that it originally came w 3 batteries, 2 for the engines and one dedicated to the generator so somewhere along the way a fourth was added. But then they hooked them all up together positive to positive and negative to negative. The charger wire is connected to the battery closest to the generator and oddly enough that battery is always strong enough to start up the gen when the other 3 batteries are dead which I cannot understand?

[g36]

Easy way without a volt meter is to disconnect all positive cables. Negatives all stay connected or tied to common point. Now Assuming no one has miswired the battery switch. Or it is bad. Turn off charger. Turn on 12vdc house.lights or some other 12vdc circuit. put battery switch in 1 and try connecting positive wire one at a time and see which one the lights come on. That's #1 then put batt switch on 2 and do the same thing. You'll have position 2. . It's fine to have 2 house batteries wired in parrallel for more capacity but depending on your house load you may be asking more than you current batteries can provide. But that's another discussion. You do need to get this figured out first.

[bud37]

Welcome to the forum......350 mariners around those years came with 3 batteries original, wired #1, #2 then both at the switch.....The third battery is only for the generator and that orange colored charger wire you see is just for the genny battery.

The other two are charged thru the switch and the breakers on your panel, clearly marked there.There is also a breaker for the genny charge circuit. Originally one battery was just #1 on the switch and so on......the entire boat would be fed from either #1, #2 or both whatever you chose.......there are a few things hard wired such as the stereo memory, CO monitors,bilge pumps etc to either the #1 or #2 position at the back of the switch. Your maunal has the routing diagram in it.The big battery feed cables in the bilge/engine area have numbers on them that match the switch positions.

As has been mentioned some pics of this set up you now have would be helpful......