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Battery Cable Splice

Old 05-23-2017, 07:07 AM
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Default Battery Cable Splice

I need to splice my battery cables to the cables from my engine. Whoever repowered just put a lug on each cable and bolted them together, then used something like Sikaflex and wrapped the whole thing about a million times with electric tape.

I want to re-do this -- as best as I can tell from measuring the conductor, the cables from the motor are 1 ga. and the cables from the battery are 2/0. Could I use something like this to connect the two, even though they are stranded cables?

https://www.amazon.com/Gardner-Bende...4RE49466K&th=1

I plan on putting some dielectric grease on the inside of the splice, and then going over the entire connection with two layers of adhesive-lined heat shrink.

Will this work? I'd rather not put another couple hundred dollars into the boat at the moment, not to mention the additional time and effort of running/making the new cables.

edit: I guess I could also use a copper butt splice for a 1 gauge wire, and just trim the 2/0 cable to fit in it. I don't have a crimper that large, but I'm sure I could swing by a shop and get it crimped. Would that be a better option?

Thanks,

Bryson
Old 05-23-2017, 07:33 AM
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If you use those screw connectors, use some ox-gard or use a marine grease.

https://www.amazon.com/Gardner-Bende.../dp/B000BODU66

The problem with those connectors, the screw bears directly on the wires which can damage the wire strands.
How about cut a shim from piece of copper pipe so the screw then bears on the shim. that way you can tighten it real tight and wont be a problem.
You can get all that from H Depot too. Those cable joiners have wire size ranges.

Harbor Freight has huge heat shrink tubing, good quality comes in white boxes, I would use that to cover it. And tape it first, consider some self vulcanizing electrical rubber tape.
Old 05-23-2017, 07:34 AM
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They make proper crimps for this.. you just need to borrow or rent the right crimp tool. I would crimp, wrap in tape, then put it in corrugated plastic tubing. Still not "right" but a quick fix.

You can remove the cables and have them crimped at a marine /auto parts store?
Old 05-23-2017, 07:41 AM
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Maybe not the best way but I spliced mine like any other wire. I inter-wove the strands (3-4 inches) and soldered it with a torch. Rubber tape and PVC tape on top of that. I checked them regularly and never had a problem.

I kept meaning to buy the right length off a bulk reel but since it was working out, I never got around to it.

Good luck!
Old 05-23-2017, 07:56 AM
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I would use a butt connector but not use any grease inside the connector. Grease which might inhibit the flow of electrons. Better to crimp the connector and then solder it.

Crimp to mechanically connect the two wires together. Solder to improve conductivity and mitigate the likelihood of any internal corrosion. Finally heat shrink the connector using adhesive lined heat shrink. The connection may very well outlast the life of the motor.

Might be better to use a butt connector for the larger size wire and then add some strands of wire as necessary to fill the side of the connector wherein the smaller size wire will connect, as opposed to reducing the number of strands in the larger size wire.

Be prepared for lots of differing opinions on the controversial subject of wire connections. Some will say that splices are heresy. Some will say that solder is the kiss of death. Some will say to only use a virgin new cable from the battery to the motor.
Old 05-23-2017, 08:10 AM
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I would replace it with one length of cable to eliminate the 2 extra crimps that could potentially fail. One less thing to go wrong. I crimp, solder and heat shrink all my connections. this tool def comes in handy
https://www.harborfreight.com/hydrau...ool-66150.html
Old 05-23-2017, 08:58 AM
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Thanks for the input guys!

I started thinking about all of the other cables I need to make, and realized how I could repurpose the existing stuff into shorter cables, like between my trolling motor batteries or from the cranking batteries to the Perko switch. Now it seems like a pretty good idea to cough up the cash and run new cables, but I need to figure out the size.

The problem I'm having is that I don't know the draw of the starter. It's a 2 stroke Yamaha V6 (150 VMAX), and the cable run is about 15' if I had to guess (batteries in the console).

I was looking at 2/0 originally, but that might not be necessary. I would obviously rather err on the larger side, but I know there's a point of diminishing returns.
Old 05-23-2017, 01:32 PM
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Originally Posted by cookbe View Post
Thanks for the input guys!

I started thinking about all of the other cables I need to make, and realized how I could repurpose the existing stuff into shorter cables, like between my trolling motor batteries or from the cranking batteries to the Perko switch. Now it seems like a pretty good idea to cough up the cash and run new cables, but I need to figure out the size.

The problem I'm having is that I don't know the draw of the starter. It's a 2 stroke Yamaha V6 (150 VMAX), and the cable run is about 15' if I had to guess (batteries in the console).

I was looking at 2/0 originally, but that might not be necessary. I would obviously rather err on the larger side, but I know there's a point of diminishing returns.
Se chart below.
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Old 05-23-2017, 01:47 PM
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Originally Posted by alloyboy View Post
Se chart below.
Thanks! Man, I feel like I searched everywhere for that. Really appreciate it!
Old 05-23-2017, 09:42 PM
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With 2 different size wires I'd take the bolted lugs over most options.

The only better options are something like a blue sea power post. Which is the exact same as the bolt, but with a mount.

The best option is to replace while cable.
Old 05-23-2017, 10:07 PM
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Copper butt splice


Crimp with hammer

Then solder and heat shrink.
Old 05-24-2017, 05:25 AM
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Hello. You should use a power post, a bit like a one stud buss bar, you can buy the lugs for the two different sizes of cables with the same size hole for the power post, this is the most secure method and probably the cheapest. Please note, soldering as the sole means of connecting two cables, especially something as important and as high amp as starter cables is prohibited, so are the connections in the Amazon link as they have no pressure plates inside them. Also dont use electrical tape if possible, get some adhesive lined thick wall heat shrink to seal up the terminals, look for terminals with a closed ended barrel to prevent moisture wicking into the cables. Hope this helps.
Old 05-24-2017, 06:24 AM
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Originally Posted by buxa View Post
Hello. You should use a power post, a bit like a one stud buss bar, you can buy the lugs for the two different sizes of cables with the same size hole for the power post, this is the most secure method and probably the cheapest. Please note, soldering as the sole means of connecting two cables, especially something as important and as high amp as starter cables is prohibited, so are the connections in the Amazon link as they have no pressure plates inside them. Also dont use electrical tape if possible, get some adhesive lined thick wall heat shrink to seal up the terminals, look for terminals with a closed ended barrel to prevent moisture wicking into the cables. Hope this helps.
Not prohibited. Just not recommended by one organization or two.

Due to the high amperage current drawn by a starter motor, a number of outboard engine makers specifically recommend the use of solder, so as to improve the current flow.

Solder has its advantages and disadvantages. In the case of a battery cable, the advantage of solder outweighs the disadvantage of solder.
Old 05-24-2017, 06:37 AM
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I've seen waterproof underground type splices that are epoxy sealed at electrical supply houses.
Old 05-24-2017, 07:04 AM
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Replace the cable that needs splicing with a new cable, one-piece, appropriate size.

It is very difficult to solder large gauge wire to ring terminal connectors. A good crimp connection is probably easier and better.
Old 05-24-2017, 08:25 AM
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Originally Posted by alloyboy View Post
Not prohibited. Just not recommended by one organization or two.

Due to the high amperage current drawn by a starter motor, a number of outboard engine makers specifically recommend the use of solder, so as to improve the current flow.

Solder has its advantages and disadvantages. In the case of a battery cable, the advantage of solder outweighs the disadvantage of solder.
Hello, just something I disagree with, unfortunately I have seen so many poorly executed solder connections that have failed due to creating hard spots, you might be okay if crimped and soldered. Solder does have its uses, I use it when installing those tiny wires for analogue to nmea connections to stop the ends from splaying out. I couldnt comment on the outboard manufacturers, I have never seen that recommendation. I do know that connections have to undergo a pull test.
Old 05-24-2017, 10:00 AM
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Originally Posted by jeffnick View Post
Copper butt splice


Crimp with hammer

Then solder and heat shrink.
this crimper is the best, cost a few bucks and makes perfect crimps every time. No need for the expensive and bulky hydraulic crimper. Use one once, and you will never go back. Mine is NOCO brand.

B
Old 05-24-2017, 10:39 AM
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Originally Posted by buxa View Post
Hello, just something I disagree with, unfortunately I have seen so many poorly executed solder connections that have failed due to creating hard spots, you might be okay if crimped and soldered. Solder does have its uses, I use it when installing those tiny wires for analogue to nmea connections to stop the ends from splaying out. I couldnt comment on the outboard manufacturers, I have never seen that recommendation. I do know that connections have to undergo a pull test.
I suspect that we might both be in agreement that a poorly constructed battery cable is not a good idea. From selection of wire size and type, crimping, soldering, sealing, routing and support.

If someone does not know how to do either of the above they would be better served paying someone to do it for them.

Here is what Mercury Marine has to say:

- use only electrical grade (resin flux) solder when soldering battery cable terminals to cable ends. Some form of mechanical connection (for example, by swaging or crimping) is also recommended, and is required if length of solder connection is less than 1‑1/2 times the diameter of the stranded area of the cable.
Old 05-25-2017, 01:41 AM
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Originally Posted by alloyboy View Post
I suspect that we might both be in agreement that a poorly constructed battery cable is not a good idea. From selection of wire size and type, crimping, soldering, sealing, routing and support.

If someone does not know how to do either of the above they would be better served paying someone to do it for them.

Here is what Mercury Marine has to say:

- use only electrical grade (resin flux) solder when soldering battery cable terminals to cable ends. Some form of mechanical connection (for example, by swaging or crimping) is also recommended, and is required if length of solder connection is less than 1‑1/2 times the diameter of the stranded area of the cable.
I agree completely with what you say, unfortunately the correct crimpers for these are quite pricey and unless someone does it a lot it is a lrge investment, quality terminals are pricey too, it´s one of those areas I would not skimp on, tinned cable and connectors, hammer crimps work okay, a properly swaged or cimped connection with the right tool and a quality heatshrink cover should last a long time, sometimes even boat builders dont do a good job.
Old 05-25-2017, 12:45 PM
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Crimping and soldering would be my recommendation. Than cover with flooded heat shrink. Make sure your splice is not in a location subject to constant movement, the crimp and solder will create locations susceptible to metal fatigue with movement.


Jim

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