Mixed Gauge Battery Cables OK?

[Leodan]

I have a fishing boat, in Ecuador, with a pair of Yamaha 200HP outboards (circa 2007). Because of the open rear-deck, the battery cable are about 20' feet long (6m). It's getting harder to start the motors and the cables do appear to be corroded so I'm thinking its time to replace them. The old cables are 2/0 gauge but its impossible to find 2/0 gauge battery cable in Ecuador (I need about 80' of it). I can get 1/0 cable and I'm pretty sure that would be OK if not for the distance from the batteries to the motors. (It would be a major pain to move the batteries closer).

So here's the situation: I can get just enough 2/0 welder's cable in black for the negatives. But the only other cable I can find is red in 1/0 (a size down) - There's plenty of that. Now I'm thinking the best solution is to use the 2/0 black for the negatives and and 1/0 red for the positives. They don't match but I can't think of any reason why that would matter - It's just a simple circuit, no? The alternative would be to use red 1/0 everywhere and label the negative cable with black PVC.

Am I OK mixing the sizes or should I use the red 1/0 throughout?

Thanks...

 

[alldodge]

I have a fishing boat, in Ecuador, with a pair of Yamaha 200HP outboards (circa 2007). Because of the open rear-deck, the battery cable are about 20' feet long (6m). It's getting harder to start the motors and the cables do appear to be corroded so I'm thinking its time to replace them. The old cables are 2/0 gauge but its impossible to find 2/0 gauge battery cable in Ecuador (I need about 80' of it). I can get 1/0 cable and I'm pretty sure that would be OK if not for the distance from the batteries to the motors. (It would be a major pain to move the batteries closer).

So here's the situation: I can get just enough 2/0 welder's cable in black for the negatives. But the only other cable I can find is red in 1/0 (a size down) - There's plenty of that. Now I'm thinking the best solution is to use the 2/0 black for the negatives and and 1/0 red for the positives. They don't match but I can't think of any reason why that would matter - It's just a simple circuit, no? The alternative would be to use red 1/0 everywhere and label the negative cable with black PVC.

Am I OK mixing the sizes or should I use the red 1/0 throughout?

Thanks...

:welcome: to iboats

Have you thought about cutting the ends off and re-soldering new ends on them, or are the cables that bad?

If they are that bad, then I would suggest using 2/0 welders cable for both Pos and Neg. Put Red tape on the cable about every foot or so, and plenty on each end. Welders cable is better then regular battery cable in most cases due to more strains and therefore better transfer

 

[Grandad]

There's no problem having different sized positive cable from negative. Going one size smaller will give a slight increase in voltage drop, but that may not be significant if you don't already have an issue with excessive length. - Grandad

 

[Leodan]

Thank you both for your responses. I did try cutting off some lengths but it did not help and now I'm all out of slack. It was a local "electrician" that advised against mixing sizes but this place is full of self-proclaimed experts - Most of them completely clueless.
Leodan

 

[Grandad]

Thank you both for your responses. I did try cutting off some lengths but it did not help and now I'm all out of slack. It was a local "electrician" that advised against mixing sizes but this place is full of self-proclaimed experts - Most of them completely clueless.
Leodan

Your electrician may have assumed that you were talking about using different cable sizes in parallel, which can be a problem, but is not your situation at all. - Grandad