Battery Cable Questions

[Jeff T]

I'm getting ready to purchase battery cable and terminal ends to install the second battery and isolator. I am planning to do the entire system in at least 2 AWG, if not 1 AWG (depending on the price).

Questions:

1-Is there any specific characteristics that I need to look for, or stay away from? I was planning to look on ebay for some, but I know I run the risk for crap. That is why I'm asking.
2-Same question for terminal ends.
3-The current terminal ends that are on the boat are the type that fasten to the battery with a wing nut. Do I need to use the type that tighten with a screw, similar to auto?
4-Does the cable have to be marine or can it be automotive grade.
5-Can you go too big on the wiring? Meaning, could 2AWG be more effecient than 1 AWG?

Thanks.

[spharis]

I'm getting ready to purchase battery cable and terminal ends to install the second battery and isolator. I am planning to do the entire system in at least 2 AWG, if not 1 AWG (depending on the price).

Questions:

1-Is there any specific characteristics that I need to look for, or stay away from? I was planning to look on ebay for some, but I know I run the risk for crap. That is why I'm asking.
2-Same question for terminal ends.
3-The current terminal ends that are on the boat are the type that fasten to the battery with a wing nut. Do I need to use the type that tighten with a screw, similar to auto?
4-Does the cable have to be marine or can it be automotive grade.
5-Can you go too big on the wiring? Meaning, could 2AWG be more effecient than 1 AWG?

Thanks.

1- not really. As long as it is a conductor its ok. Name brands and cheapos are all made by the same Koreans/Japanese
2- see 1
3- Use the wing nut terminal type.
4- As long as it is insulated, its good, so not really much difference. Marine usually has a different type of coating, but it is stiff.
5- No, in high amp situations the larger the btter.

[Jeff T]

As Always...Thanks.

I was reading about the tinned copper by Ancor (I am assuming this is the coating you are referring to). Is tinned copper worth it? You also mentioned esoteric in a PM, what is that?

Just so that I'm clear...the order of size from smallest to biggest would be:
4AWG, 2AWG, 1AWG, 0AWG, 1/0, 2/0, and so on?

[mtnsmith]

The tinned means the copper wire itself has tin on it to help it resist corrosion, which is why it is better for use in a marine environment. The insulated in question 4 meant just that it has a covering on the outside of the wire. My old VW bus had a negative battery cable that was not insulated. The size order is correct as well.

[spharis]

If I'm not mistaken, the tin is just on the ends or pre-cut wire, the part that is exposed. The tin is not under the coating. Esoteric is a brand name. I just happened to pick it up cheap. And yes those sizes are correct.

[lee]

Tinned wire has tin that runs all through the wire to resist corrosion. I would think you would need to go with a 2/0 if the wire is going to be used for starting.

[chpthril]

I bought some stuff from this Ebay store. They will make your cables for you ( for a small fee if you buy cable, ends and shrink tube) if you know the demensions. They sell marine rated cable, which I recommend.

http://stores.ebay.com/Genuinedealz_...Q3amesstQQtZkm

[Jeff T]

There will be wire used for starting. So, do I need 2AWG or 2/0? I will be re-running most of the cable. I have the exact plan and I won't until I get started. With that said, I'm installing an isolator. Therefore, there will be some new cable used for starting (at a minimum--isolator to start batt).

[spharis]

JeffT, aren't you just going to re-use the starter to battery cable that is already there?

2/0 is good for ~190 amps, 2A is good for about 125A @ 16 feet; you should be able to get the current draw of the starter somewhere.

Tinned wire has tin that runs all through the wire to resist corrosion.

Thanks for the education.


How does tinning the inside of a sealed cable going to prevent corrosion though? I tin all battery cables on the ends to the sheathing, then they are shrinked.

[Jeff T]

Yes I plan to reuse the starter cable. But I still have to run all the cable for everything else:
-Alt to iso (may reuse the alt lead already in place)
-Iso to Batts 1 & 2
-Ground from Batt 1 to Batt 2.

Will 2 AWG work for all these?

[chpthril]

Yes I plan to reuse the starter cable. But I still have to run all the cable for everything else:
-Alt to iso (may reuse the alt lead already in place)
-Iso to Batts 1 & 2
-Ground from Batt 1 to Batt 2.

Will 2 AWG work for all these?

I think 2AWG will work just fine for you 2nd batt install, thats what I went with.

[lee]

How does tinning the inside of a sealed cable going to prevent corrosion though? I tin all battery cables on the ends to the sheathing, then they are shrinked.

Moisture will find its way inside the sheathing. Take a look at an older boat and grab a wire cut into it and the wire will be corroded even in the middle of the run.

[mtnsmith]

I completely agree with what Lee said. I have always been around saltwater used boats and the wiring is especially succeptible then. I have had to run new wire up a 35 foot mast every other year on more than one occassion, even with tinned marine wire.

[spharis]

I just don't see how moisture can get into a properly encased cable, unless it sat in water. I think the wire ends were not treated properly.

[Jeff T]

I'm now trying to figure up how much cable I need. My plan was to only run NEW ground from the current battery to the new battery. I was going to leave the current grounds in place (original battery is already grounded).

Now, as per this thread, I am planning to purchase 2 AWG cable for power and ground. If my current grounds are larger or smaller than 2 AWG and I install 2 AWG for my new length of ground wire, will that create any issues?

I guess the same question would need to be answered for power as well. I'm going to use the current alt feed to run to the iso, and run new 2 AWG power from iso to both batteries. I don't know what size is currently there and I won't be able to check before I need to place an order.

Any advice is appreciated!