1/0 Battery Cables
 

I have 2 Blue top Optima batteries that are in parallel, My current setup has a single 4 gauge wire running between both batt's, I just purchased 4 battery terminals that will allow me to run dual 1/0 wires between the batt's
Will this damage the batteries? is there a benefit from doing this?

Thanks
Bryan
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It won't hurt anything, just allows for a very large amp flow.

Won't hurt a thing.

Bigger is better 99% of the time when dealing with batteries.

Current flow is like a hose.....the bigger the more flow. Just make sure to have the same sized grounds also.

So I have 2 1/0 (Pos and Neg) in parallel and 1 ea going to the starter and block coming from the battery switchhttp://i129.photobucket.com/albums/p...psb120c066.jpg
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How are you hoking up the wire from the alternator? Those cables look great!!

I already have 1 cable each coming from the block and starter going to the battery switch, now I need to make a wire to go from the alternator to the batteries..... Thanks BTW

Why do you need two 1/0 cables hooking one batt to the other ?

Check at the starter, you may already have an alt wire there. I'd just run a new wire from alt to starter if that's the case.....unless you have a bat switch.

Double 1/0 on such a short run between batteries is a waste for almost every application I can think of.
Upsize cable to carry high amperage or reduce resistance over a distance. There would be no draw on a boat between two batteries such a short distance that would necessitate a double run. Especially if the load being carried off is only using 4ga.

Are these your start batteries? stereo bank?

System would be better served with 1/0 neg going to block given the high amp load an engine starter can demand.
1/0 should be used throughout the switch if that is how positive charge is distributed to engine starter.
The other 1/0 should be for pos/neg stereo if you are over 1500w.
4 ga should be plenty overkill for an alt unless you are over 200A as it should be for the 2' between batteries.

These are my start batt's and from everything I have taken out the whole boat needs rewire so I thought I would start with the most expensive and work my way down. Currently I have 1/0 from the block (Neg) and starter and now working on adding it to the batt's. Then running 4 gauge to the panel (From the battery switch).
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Guess I want it done right so there are no more worries (In the near future)

Judging from the boat in your sig, single engine.
Assuming these are the only two batteries on the boat?

I would run neg 1/0 between block and starter. back to neg terminal. Between battery neg's can be 4ga but since you have the 1/0 cut, fine as long as you are not running big stereo. (this is all assuming you want to use only the new terminal connections and are not using the posts for anything)
If running over 1500w stereo, you need 1/0 to the stereo distribution block.

Run pos 1/0 from each battery to your switch and then on to the starter if you have 1,2,both switch. If you have on/off only then combine the batts with either 4 ga or 1/0. Same stereo connections as neg.

4ga up to the panel is WAY overkill unless you are running up to 1000w stereo off the same lead too but wont hurt. Factory is usually 10ga, I would not be opposed to 8ga. Don't forget equal neg back.
I would not recommend running stereo amps off the primary panel regardless. Amps generate extra, extended heat that tends to make connections fail. IF one of these connections fail, all power to the panel can be lost instead of just stereo.

Use di-electric grease on all connections to minimize corrosive effects even when using tinned wire.

..........Looking back at your last pic, I see a 1/0 neg on the post already. Take my advice for what it is. There are many ways to set up the electrical depending on your equipment and intentions.
We need a lot more info on your overall components, draw requirements and expectations. I can say 99.999%, double 1/0 between two batteries is a waste beyond overkill. The pos parallel is a possible setup but not often used if you have a 3 way switch?

Yes this is a single engine 502, and if I run my current setup as seen below I can not isolate each battery with my switch, With that said I am going to rub 1/0 cable from each positive to the switch then run 4 Gauge from the the batteries to the panel where I am going to install a new fuse/ breaker panel.
Is is overkill... Probably, but I want to avoid any future electrical problems and know that I can add devices in the future and not worry about overloading the wire


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The coast guard is going to want the battery terminals covered.