Extending The Battery Cable

[two stroke mick]

I just got my rib back but the battery and the fuel tank are in the same compartment i.e. under the seat. I want to move the battery to a seperate compartment which is located in the front of the seat unit. The cable that connects to the battery is not long enough. I need to add approximatly 2 foot (600mm). The engine is a 60 hp ETec.

In your opinion will the extra 2 foot cause an excessive voltage drop. The cable that came with the engine is 9 foot.

TSM

[jwalker]

Use cable at least as fat as your present stuff and make a good quality joint and it'll likely be fine.

[hank]

I would not splice the wire to make it longer
get a longer wire and larger size
( the smaller the number the larger the diameter the wire)

[two stroke mick]

The cable that came with the engine has been finished with a ring (looks like a lollypop wiith a hole in the middle). I was thinking of using a pre made section of cable with lolly pop connector on each end and connect one end to the battery and connect the lollypops on top of each other and tighten them with a SS bolt.

http://www.vehicle-wiring-products.e.../battleads.php

Using the SSP/N wire 600mm long.

[Dirk Diggler]

The correct way is to use butt connectors and 2 layers of heatshrink.

[Poly]

Originally Posted by two stroke mick

The cable that came with the engine has been finished with a ring (looks like a lollypop wiith a hole in the middle). I was thinking of using a pre made section of cable with lolly pop connector on each end and connect one end to the battery and connect the lollypops on top of each other and tighten them with a SS bolt.

dirk is of course correct about the correct way. However what your describe is what I have done all covered in two layers of heat shrink. Its a bodge but it works. I only have a 20HP and it has a cord start so I decided that it didn't really matter anyway; if not being able to start your engine would be more critical for you then your conclusion may be different.

[matt h]

Dirk is correct, this is the only failsafe way, the other nut and bolt way would be considered a bodge!!

[BruceB]

Personally If I was to extend cables rather than replacing them I would in all likelihood solder them by splaying and butt jointing them and then blowtorch the joint with plenty of flux and solder to get a good joint. Then cover with adhesive type heatshrink.
I would be happier with this type of joint electrically and mechanically over a crimp. In fact I solder all my crimped connections in addition to crimping them.

[jwalker]

Originally Posted by matt h

.... this is the only failsafe way,

Pish. You think a crimp is failsafe?

...the other nut and bolt way would be considered a bodge!!

By some, maybe but a nut and bolt will put a pressure of many tons across the joint. After all, when the cable terminates at the battery, it'll just be held to the terminals by.......a nut and bolt.

[jwalker]

Originally Posted by BruceB

Personally If I was to extend cables rather than replacing them I would in all likelihood solder them by splaying and butt jointing them and then blowtorch the joint with plenty of flux and solder to get a good joint. Then cover with adhesive type heatshrink.
I would be happier with this type of joint electrically and mechanically over a crimp. In fact I solder all my crimped connections in addition to crimping them.

Agreed.

[Nos4r2]

The ONLY thing I'll say on solder V crimp is there's a reason it's illegal to solder connections on aircraft.


Personally, I wouldn't join the cable at all. I'd make a new cable.

[Hightower]

I'd make a new cable length too. Everything else is a bodge, not worth the risk of the cable detatching, corroding or setting electrolisis in action by getting or allowing the negative and positive joins to get salt water in them.

[Tim M]

This might seem like a really silly question, but why? I have always been of the opinion that a soldered joint is a lot better than a crimped joint, especially on a boat where a crimped connection can work un-done.

[Poly]

Originally Posted by Hightower

I'd make a new cable length too. Everything else is a bodge, not worth the risk of the cable detatching, corroding or setting electrolisis in action by getting or allowing the negative and positive joins to get salt water in them.

Hightower - not disputing that a whole new cable would be a better solution (although probably expensive, and IIRC not straightforward to fit at the engine end). However: You presumably) have crimped on connectors at both ends of your cable (one at the battery and the other in the engine) why are these any less likely to "detatch" than a connector in the middle? Why is corrosion any more likely to get into these connections (if correctly made and enclosed) than any other electrical connection on the boat? I'm not sure what your electrolysis concern was.

My main concern about the bolt approach (as bodged on my boat) is that if any sharp edges on the nut bolt wear through the protective casing there is a small risk that both positive and negative connections wear through and could short.

[jwalker]

Originally Posted by Polwart

My main concern about the bolt approach (as bodged on my boat) is that if any sharp edges on the nut bolt wear through the protective casing there is a small risk that both positive and negative connections wear through and could short.

Bend them, smooth them, pad them, clamp them, stagger them, sleeve them, box them, and any other number of thems.
Be rational not emotive...as you obviously have been since you used a bolt.

[Poly]

Originally Posted by jwalker

Bend them, smooth them, pad them, clamp them, stagger them, sleeve them, box them, and any other number of thems.
Be rational not emotive...as you obviously have been since you used a bolt.

Jeff thats pretty much what I did - they are staggered offset about 4 inches from each other, sleeved in shrink wrap, secured together with cable ties and all wrapped in insulating tape (it doesn't look pretty - but that reminds me that the joint underneath may not be prefect either!).

Like all of the primitive electrics on my boat it was only meant to be a temporary measure (in this case to test the battery and engine) but actually worked OK so has just remained. Its lasted 2 1/2 years so it can't be too bad. (the last time I went to the boat the joint was under an inch of ice/snow and still seemed to be working fine).

[two stroke mick]

I considered a whole new cable. But it is hard to find the exact spot where it terminates without stripping off a considerable amount of kit.

[Dirk Diggler]

Originally Posted by jwalker

Pish. You think a crimp is failsafe?By some, maybe but a nut and bolt will put a pressure of many tons across the joint. After all, when the cable terminates at the battery, it'll just be held to the terminals by.......a nut and bolt.

That terminal, held by the nut and bolt, will be "crimped" onto the cable, same as a butt joint, but with more to go wrong. Take my word for it, I do this as my job, a Butt joint is the correct way, unless your prepared to go to the expense of new cables. Which you'll have to crimp ends on to!!!

[Poly]

Originally Posted by two stroke mick

I considered a whole new cable. But it is hard to find the exact spot where it terminates without stripping off a considerable amount of kit.

Even if you can you may find that the fitting that needs to be crimped on is bigger that the hole in the cowl (it is on mine) so the fitting needs attached after the cable is fed through - either you need the right tool and skills to do it right or you will have to pay someone who has. I have proper crimp tool but it doesn't go that big so that was the end of that approach.

[Dirk Diggler]

Originally Posted by Tim M

This might seem like a really silly question, but why? I have always been of the opinion that a soldered joint is a lot better than a crimped joint, especially on a boat where a crimped connection can work un-done.

That's assuming you know how to solder, where as any fool can crimp!