welding cable as battery leads?

[DonMacN]

Folks,

Haven't posted for a while since i got the boat up & running, but wonder if you wouldn't mind helping out?

It a 2008 model HondaBF90, supplied with the seemingly standard fit 'ridiculously short' power cables. I've had issues with join between these and the 'extensions' I had made up and now want to fit complete cables from battery to motor. As it's a dive RIB there's often a lot of water sloshing about the deck and cable joins just can't be a good idea - never going to know when they'll cause a problem.

My question is what rating cable do I need - the 'extensions' I had made up are from 35mm2 cable, but they're just a little bit too 'chunky' to fit easily into the grommet/gland that enters the cowling - though they will work at a push.

The OE cable is labelled AV20, but I can't find any spec for that. My dealer's been in touch with Honda UK, who apparently need to phone Japan to ask....!

I'm guessing the main draw is the starter motor, but does anyone have any good info on all of this?

My dealer is also raising the issue of the 'waterproofness' of welding cable. I'm assuming it's OK for a dive RIB application?

Any advice appreciated.

Cheers

D

[BruceB]

Well I have used it for some years and had no problems. As long as both ends are well tinned and sealed (and not lying in any water) then I can't see how they would be any real problem, if water can't be drawn in then it can't rot the copper.
Certainly the difference in cost is such that even if I had to replace it every few years (and I haven't) it would still be worth using it due to the cost difference............

[DonMacN]

Cheers Bruce,

THat's what I thought myself, but the dealer just put a doubt in my mind. It seemed to me that, quite apart from water getting in, the real danger in a work situation might be current leaking out, so the cable must be made to a decent spec.

Seems there's single insulated and double insulated stuff - are you just using the 'single' stuff?

Price up here for 35mm2 is somewhere around £4/m.

Hopefully some other kind soul can answer the question about cable rating.

Ta

D

[Erin]

The cable size will depend upon the length of run. I believe 25mm would be adequate on most boats for that engine, but if you can go 35 it'll certainly not harm.

[DonMacN]

I knew I'd leave out some important information! The cables I've just taken of are 5.4m long.

[jwalker]

Go for the biggest diameter you can get through the grommets because that'll give you the lowest voltage drop. Welding cable is good. The strands are often tinned which will help prevent corrosion should you be unlucky and get water into them and the strands are small diameter too which gives the cable very good flexibility, unlike some starter motor cable. The outer is tough and heat resistant and can take a fair amount of abuse. Other cables I've used are heavy duty jump start cables, usually not tinned though but have the advantage one is black and the other is red if that matters to you. They too are flexible so easy to route and reroute if necessary.

[Downhilldai]

Originally Posted by jwalker

Other cables I've used are heavy duty jump start cables,

I've got some of them


I made them out of welding cable.

[jwalker]

Originally Posted by Downhilldai

I've got some of them


I made them out of welding cable.

Ah, but are they pretty coloured red and black like mine.

[Downhilldai]

Originally Posted by jwalker

Ah, but are they pretty coloured red and black like mine.

Yes, of course.




Well, the bits of insulating tape on the clips are anyway.

[BruceB]

I am sure I have red and black welding cable, if pushed I can check through the boat file and find out where I got it as I will still have the receipt in there somewhere.
Its fine stranded and flexible but I don't remember it being tinned. 35mm if I remember right.