new battery cable questions

[boatman37]

So where is the best place to buy new cables? Need then about 8' long or so off the top of my head. Have to get better measurements before ordering them. Any special ones for marine applications or will any battery cables do? I have 2 batteries, a Perko switch, and an isolator. Not even real sure where they run or how many I need without looking. Just happened to notice a little greenish corrosion on my one wire and my volt meter never goes over 12. Been fighting this since last season. Have a rebuilt alternator. Figured by replacing these I can eliminate that. Not having any problems other than the volt meter reading and my depth sounder flashing wrong numbers after a short run. If I switch to my house battery it is fine then.

What gauge should I get? 2 or 4? Thought maybe replace one cable at a time. I already checked and cleaned the connections at the Perko switch and starter as good as I could.

 

[Silvertip]

Did you clean the ground cable (both ends) as well. Doesn't do any good to clean one (or just one end) if the other cable cable corroded ends. You very likely do not have all bad cables. Look at them carefully to see if corrosion has worked it's way under the insulation at the cable ends. If it lumpy in that area new cables are probably in order. Otherwise, a good cleaning (making each end shiny bright) should be all that's needed.

 

[boatman37]

Cleaned a bunch of connections last year. Can't say for sure I got all of them. Can't see a few of them so just went by feel. But the one positive battery cable definitely had the green tarnishing between the lug and insulation (about 1/2" gap between the lug and insulation)

 

[Scott Danforth]

the cable gage depends on the load

best place to get them is to make them yourself Iboats also sells cables https://www.iboats.com/shop/electrical/boat-wiring-and-cable/marine-battery-cable.html

your local hardware store may have everything in stock and the tools to crimp the ends. same goes for worst marine or any of your local marinas if you need them today

get the tinned marine cables.

 

[dingbat]

Reasonable, quick and to order....

http://www.genuinedealz.com/1-0-awg-custom-battery-cables

 

[boatman37]

Thanks. Going to check things out a little closer this weekend and see if I might have missed a few ground connections and also going to see what cables and lengths I will need. So far there have been no issues but our runs are usually limited to 15 miles at the most, and usually closer to 5 but we hope to take a longer cruise this summer (about 50 miles round trip) and want to make sure everything is up to par first. The blinking depth gauge after 15 minutes or so of running is an indicator something is off. And switching to the house battery fixes the issue so something awry there.

 

[Lightwin 3]

the cable gage depends on the load

best place to get them is to make them yourself Iboats also sells cables https://www.iboats.com/shop/electrical/boat-wiring-and-cable/marine-battery-cable.html

your local hardware store may have everything in stock and the tools to crimp the ends. same goes for worst marine or any of your local marinas if you need them today

get the tinned marine cables.

Scott is right.

I had some cables made at my local NAPA store. They asked me if they were for marine. The wire is different.

As far as size, the bigger the better within reason.

 

[Scott Danforth]

Thanks. Going to check things out a little closer this weekend and see if I might have missed a few ground connections and also going to see what cables and lengths I will need. So far there have been no issues but our runs are usually limited to 15 miles at the most, and usually closer to 5 but we hope to take a longer cruise this summer (about 50 miles round trip) and want to make sure everything is up to par first. The blinking depth gauge after 15 minutes or so of running is an indicator something is off. And switching to the house battery fixes the issue so something awry there.

what is battery voltage at battery and at alternator terminal

running you should be about 13.6-14.2 volts
key off, battery should be 12.6 volts or higher (12 volts is fully discharged)

 

[boatman37]

Can't remember now. I checked it all last year but they weren't quite that high. I think about 12.5 or so running. Batteries are fairly new. House battery new 2 years ago and cranking battery new 3 years ago. Alternator was rebuilt and bench tested to be good last year. Thats what leads me to believe cable issue somewhere. If the alternator is putting it out but the battery isn't getting it then it's getting lost somewhere. And i bought one of those DB Electrical alternators off eBay and had it on for awhile and no difference so alt. is definitely not the issue.

IIRC battery voltage with key off was a little over 13, maybe 13.5 or so but whatever it was it didn't raise any flags. when it is running is when i see the issue