wire connecting dual batteries

[blipship]

I have a dual battery system in the boat i recently baught. I noticed that there is a wire connecting the two batteries negative post together. The system has a switch to use 1 ,2 or both. Is this supposed to be like this. Sorry if my question is a stupid one.

 

[Cobotr]

Re: wire connecting dual batteries

Yes, it's can be that way. The black wires are the system ground wires. These ulimately end up at the engine block. They can also be wired seperately from each battery to the block.

 

[blipship]

Re: wire connecting dual batteries

This wire does not ground out though...it just connects the negative terminals of the two batteries. It is a small gauge wire. From what I see I dont see a ground out wire <br /><br />I know it works fine like it is...just wanted to make sure that its supposed to be like that.

 

[golfer]

Re: wire connecting dual batteries

Hey Blip,<br /><br />The batteries are connected together with black, at the black posts. But, if you look, you will see that another black cable leads to one of the negative terminals, that is attached at the other end, most likely at the block as a ground. They have simply grounded one battery to another, to an actual grounding source, i.e., the block.

 

[Boatist]

Re: wire connecting dual batteries

Blipship<br />Yes both batteries need to have a heavy wire back to the block or engine ground. It is ok to go from one battery neg to other battery neg but wire should be at least as large as hot wire to your starter. This way if you ever switch to battery 2 to start boat wire will not burn up.<br /><br />Not a good idea to turn switch with the motor running unless your switch is a make before break type. Even if it is do not turn off with motor running.