Battery Cables and Crimpers - SailNet Community
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Battery Cables and Crimpers

Was looking over the existing connections between my two batteries this weekend and trying to figure two things: current cable size and crimping.

The cable between the negatives on the two batts is marked "2AWG". Between the positive of #2 to the "Both" post on the switch is marked "4 Gauge". Meanwhile, from the positive of #1 to the "1" post on the switch is an unmarked cable (as far as I could read) that measures .62in diameter on the outside. Any idea what size that one might be?

My two batts aren't close--all the pre-made cables seem to stop at 4 ft--where do you get a 10 foot cable with lugs?

Thanks.

Tom

Tom K

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Old 12-01-2009
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The 4 awg wire is a bit light and the 2awg might be as well. Here's a link to an easy to use wire calc. Just put in the voltage drop (3%), round trip distance, and amperage and it will give you the gauge. AWG by wire length/amps calculator
As far as wire of the right length with lugs you can get custom cables made quite affordably at Genuinedealz > Custom cable, custom battery cable, custom cable assembly, battery cable . Just specify gauge, size of hole in lugs (1/4, 5/16, 3/8) and heatshrink and they charge \$1.00 per end labor.
Hope this helps.

Brian
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I like using this page for computing line losses. If you want a real-life test, run your system under heavy load for a couple of minutes, then touch the cables. If you feel any warmth at all you need to increase wire size. The bigger you go the less loss you will have (but the prices really grow as well).

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mitiempo, Genuinedealz looks perfect--thanks for that! And thanks to you and Zanshin for the size calculators--I'll definitely put those to use as I figure my new setup.

From one of the charts at Genuinedealz, I see that my .62 in. OD mystery cable is likely AWG 0, which is currently used from switch to starter and from #1 batt positive to switch lug "1". I'll be studying a book on electrical systems, but would anyone care to give me a headstart on why a lesser cable can connect two batteries in parallel than is needed to, say, go to the starter from the bank? I get that the starter is a big draw, but does this mean that less current is flowing between the batts than is flowing out to the starter placing the demand?

Thanks again.

Tom

Tom K

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Old 12-02-2009
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I love Genuinedealz. The heavy duty lugs are the best I have found. I get my shipments in about 3 days. Great quality at half of WM for wire. Me just a happy customer.

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Nigel Calder and Jon Payne and both great reads. Check Amazon.com for boat electrical books. Read more than one.

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Old 12-02-2009
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I would make the cables the same size. sized for expected draw of starter etc, and for convenience make them all the same size. You`re ahead of the game compared to me - my cables to the starter were old, corroded non-tinned and maybe 6ga. All new now and much larger.

Brian
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Quote:
Originally Posted by badsanta View Post
Nigel Calder and Jon Payne and both great reads. Check Amazon.com for boat electrical books. Read more than one.
Calder is on my Christmas list--I'll check out Payne.

Tom K

2000 Beneteau 331
Northern Chesapeake Bay

Ambition is a poor excuse for not having enough sense to be lazy ~ Steven Wright
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[QUOTE= would anyone care to give me a headstart on why a lesser cable can connect two batteries in parallel than is needed to

Thanks again.

Tom[/QUOTE]

The cable size required is a combo of load and length

For any load the longer the cable the bigger it needs to be

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Tommays
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Quote:
Originally Posted by mitiempo View Post
I would make the cables the same size. sized for expected draw of starter etc, and for convenience make them all the same size. You`re ahead of the game compared to me - my cables to the starter were old, corroded non-tinned and maybe 6ga. All new now and much larger.
Well, mine don't appear to be tinned and these are 22-yr-old cables, but I was hoping to not have to replace all. We'll see--will be doing a more thorough inspection soon. Is it really common practice to run 0 AWG between batts?

Tom K

2000 Beneteau 331
Northern Chesapeake Bay

Ambition is a poor excuse for not having enough sense to be lazy ~ Steven Wright
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