Battery Wire Gauge

helicopterjim

helicopterjim

Hero member
Location
near Lone Butte, BC, Canada
Hello ..... I tried to search the forum for the answer but no luck and I?m 4 hours away from my bikes for the next several days.

Looking for the wire gauge of the battery/ground/starter leads. I have access to some good quality wire and terminals and want to make some replacement wires. I would guess 2 to 4 gauge and would probably make it 2 AWG gauge regardless but don?t want to stray too far from original size.

Thank you
Jim
 
If you're talking AWG Jim, 6 will be closer to original spec (13.3mm2 equivalent according to the table I checked).  I prefer to use 16mm2 here but that can be awkward to route unless it's super flexible & multi stranded.
You'll struggle to fit 2 gauge and 4 will put a strain on terminals due to limited bending radius.  You may have problems finding lugs with a small enough hole too.
 
Car stereo squirrels use some nice heavy gauge fine strand cables to run their 1000 watt power amps. I think you can get 4 or 6ga. and it is really flexible. Would be a good source of terminal ends too. Plus it comes in pretty colors!  I redid the battery cables on a CB550 with some 8 ga. and it worked out fine.
 
I used welding cable for my Jota's battery and starter leads. I don't recall the wire gauge, but it's at least double the x-sectional area of the original leads. It has multiple strands of very fine wire so is quite flexible.
 
helicopterjim said:
The number of strands and the purity of the copper seems to be important as well.
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Not really. Copper of normal industrial purity is perfectly OK, as Rob alludes with his snake oil comment about the 'oxygen free copper' bullshit.
Number of strands is relevant when considering flexibility, but has little to do with current rating. For most practical purposes, the only parameter you need to consider for current carrying capacity is the total cross-sectional area of the conductor.


PS: For those who want to get pedantic about cross sectional current density and skin effect in a conductor, let's not confuse the issue. Cross sectional area is a good enough yardstick for our purposes, and that's how conductor size is measured in the real world anyway.
 
Dellortoman said:
Not really. Copper of normal industrial purity is perfectly OK, as Rob alludes with his snake oil comment about the 'oxygen free copper' bullshit.
Number of strands is relevant when considering flexibility, but has little to do with current rating. For most practical purposes, the only parameter you need to consider for current carrying capacity is the total cross-sectional area of the conductor.
Click to expand...

I agree that the number of strands is relevant for flexability ........ but I have seen some shite wire available that looked more like aluminum than copper. Increasing the gauge to 4 AWG was probably the biggest factor. I'm not sure about the oxygen free part myself ..... I just know that upgrading the wiring on my Elefant made it start without having to put the battery tender on overnight. Stock wires were crap and too much voltage drop. Ducati M900 Monster also started much better ....... touch of the starter and away she went .... rather than cranking over two or three times. I will do my Guzzi and 3C next ..... just figured I would make my own kit this time.

Jim
 
helicopterjim said:
I have seen some shite wire available that looked more like aluminum than
Click to expand...

Aluminium is a pretty good conductor too (although copper is better). When I worked on EHV transmission lines and substations, most of the conductors we used were aluminium.

It's not suitable for automotive use though because it's not very tolerant of vibration. It work hardens and will eventually break if subject to flexing.

Silver is the best conductor, about 1.05 x copper. Why don't you use thick silver cables for your battery?  ;)

Another possibility would be to use a superconductor material. Then it wouldn't matter how thin your cables were, but you'd only be able to ride on very cold days - might not be a problem in Canada.
 
helicopterjim said:
Yep. I guess those fancy braided ones are probably hard to find ....... but they look cool.

Jim
Click to expand...

Belt and Bevel have them Jim and no doubt other suppliers.
Shipping might be an issue but.
https://beltandbevel.com.au/ducatiparts/copper-battery-strap-earth-point/
 
Here in the USA the local NAPA store has an excellent selection of ground (earth) cables. AIRC I found a quality copper heavy gauge braided cable that worked just fine. It was intended to a riding lawnmower or garden tractor. :o

You fellows over the pond try some of the supply stores for garden tractors?
 
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