Wire Ampage

[Biggles]

Could any one tell me what ampage of wire ( In the UK wire seems to be sold in ampage rating and isn't always identified by AWG )would be ideal for connection between the engine and battery for the charging circuit of a 50 Hp motor pushing out 16.4 Volts.<br /><br />I have ordered some 27.5 Amp wire but am concerned it won't be up to the job. Maybe I should have posed the question here first.<br /><br />Many thanks.

 

[chuckz]

Re: Wire Ampage

That wire if anything is overkill for charging the battery. You should check your manual, but the charging system output is probably around 12 amps. If this wire is also used for starting the engine, it's way to small.

 

[Biggles]

Re: Wire Ampage

What ampage would be correct if the wire is also used for starting the engine ?

 

[Paul Moir]

Re: Wire Ampage

If this is for your Merc, then it should have supply a maximum of 9 amps. I see '27.5 amp' wire has a cross-sectional area of 3.0mm, which makes it somewhere between #13 and #12 by the AWG. That should be good for around 20 feet of wire to the battery.<br />Hope that helps!<br /> Reference 1 (what 27.5A cable is)<br /> Reference 2 - sq-mm to AWG <br /> Reference 3 - Ancor wire calculator<br /><br />EDIT: I would want #4 for starter cables - which works out to 170 amp wire (actually, half-way between 105 and 170). But it depends on how far away the battery is.

 

[Biggles]

Re: Wire Ampage

The battery to starter is about 5 feet.

 

[Paul Moir]

Re: Wire Ampage

170 amp would do nicely then, although 105amp would work too. If it were mine I would go for the heavier wire, since it'll put up with degradation better. By the way, wire ment for welders makes excellent battery cables - they're far more flexible and have heavier insulation then regular battery cables. Sometimes it's hard to find stuff that isn't black only, but a little red electrical tape can be used to identify it at the ends.

 

[18rabbit]

Re: Wire Ampage

I just commented on the use of welding cable for battery cable. See here.

 

[Paul Moir]

Re: Wire Ampage

Respectfully, I disagree. As proof I hold up a set of original Johnson outboard cables that have seen 40 years hard service in salt water. They are not tin plated and although they have their fair share of greenies, the failure point was the insulation. I strongly belive the thicker insulation and more flexible conductor will lead to a longer life with heavy copper cables running to an outboard rather than conductor failure. <br />If we were talking about a wire for a bilge pump, I would have no argument.

 

[18rabbit]

Re: Wire Ampage

Well, I respectfully agree with you. And your ‘proof’ is well received. Excellent, those cable are. <br /><br />The overall quality of welding cable makes it a good choice. If you use the closed ended lugs and seal it up with adhesive lined heat shirk I think it will be a whole lot of years before there is a problem, IF there even is a problem. The use of open-ended lugs allows an opportunity for the greenies to get started right away on raw copper so I would definitely avoid those.

 

[imstillatwork]

Re: Wire Ampage

The welding cable was my post, glad I could find more information here too! I have also since found tin plated welding cable that is still cheaper than most marine label stuff.<br /><br />I think the closed ended lugs and some shrink tube and It might be a good idea.

 

[Paul Moir]

Re: Wire Ampage

Tin plated welding cable: I've never seen that before but I think it would be ideal. Oh well, no battle royale this time.

 

[Realgun]

Re: Wire Ampage

I am going with yellow for all gound wires what can I do for that? As pertaining to battery cables.

 

[18rabbit]

Re: Wire Ampage

Realgun - Black cables with colored heat shrink. I can only find the adhesive-lined, heavy-wall heat shrink in black and red so that’s what I use. If you wanted to you could put some yellow thin-wall heat shrink over the red adhesive-lined thick-wall for color coding.<br /><br />Or, if you want to really impress the ladies…there is expanding cable sleeve that comes in all kinds of colors. Braided PolyEthylene Terephthlate (PET) is really common. NOTE: some cable covers require cutting with a hot knife (heat up an xacto-blade on your kitchen stove), some you don’t. The braided PET sleeve I have requires a hot knife. See the FlexoPET here. I pay about $35/200-ft spool. I only have black PET sleeving or I would give you some. Google and you'll find places that sell it by the foot.<br /><br />Btw, do you know of a loft development in Albuquerque called the Gym Lofts? It is an old, historic high school near a hospital that is being converted into lofts.

 

[Realgun]

Re: Wire Ampage

Thats the Old Albuquerque High School. The Loft your refering to is be a renovation of the Gym. The Library is Lawyers offices. I would not buy 1 as the parking is in the street and where would I put my boat? <br /><br />There was a heck of a fight over that H.S. Finally somebody popped their head out. Now the homeless have to go to a shelter.