Starter motor cable to battery upgrade

[caduceus]

As I'm in the process of replacing the starter motor, I thought I'd replace the big red cable from the battery to the starter, and the smaller red cable from the starter to the big fuse. Some of the fine strands at the ends are snapping and not looking too clever.

What is the largest/optimum size cable I should buy? Can you go too thick, or will it just carry the amps it needs however thick the core cable is?

Cheers
Cad

[WorAl]

Don't quote me on this but I think the cable on mine is 4G which is enough to carry the amperage and have just made some jump leads from it myself.

Not cheap though.

http://www.maplin.co.uk/Module.aspx?ModuleNo=6208

[itiejim]

The thicker the wire the lower the resistance.

[Marian]

It says on the link that it's not to be used on starter motors

[jhfozzy]

Try an auto electrical garage.

We used to cut and make starter cables up to spec with ends and everything, but it seems that we've stopped now and only sell it by the reel. Saying that, we've always got some spare lying around the place.

[WorAl]

Marian said:

It says on the link that it's not to be used on starter motors

I know, its bloody stupid, they just wont guarantee it, its battery cable, where else is it to be used apart from amplifiers........but, they don'e guarantee it for that either.

[jhfozzy]

Marian said:

It says on the link that it's not to be used on starter motors

Average current of a starter motor is about 300A+, that cable is rated at 70A. Nuff said.

[Marian]

WorAl said:

Marian said:

It says on the link that it's not to be used on starter motors

I know, its bloody stupid, they just wont guarantee it, its battery cable, where else is it to be used apart from amplifiers........but, they don'e guarantee it for that either.

Seeing as I'm just about to change my starter and alternator I'd be as well changing the cables as well, I take it this cable is fine to use from the alternator to the big fuse and also from the big fuse to the battery and also from and to the starter?

[WorAl]

I would say so yes Marian, but I've only used this for jump leads so no guarantee, I would just check first. It's 4G cable it should take about 120 amps no problem.

[morebeanz]

And what about this point?

jhfozzy said:

Average current of a starter motor is about 300A+, that cable is rated at 70A. Nuff said.

[FarmyardPants]

Just loop it through the cabin, it can double as a heater.

[caduceus]

jhfozzy said:

Marian said:

It says on the link that it's not to be used on starter motors

Average current of a starter motor is about 300A+, that cable is rated at 70A. Nuff said.

So that cable is 21mm multi strand and its not good enough? What should I be looking at then? 30mm multi strand, or something like 25mm 8 strand (thicker strands)?

[shoggyraminator]

You can always use meter tails if you want something really thick. http://www.tlc-direct.co.uk/Products/CA35TBLslash5...

[WorAl]

morebeanz said:

And what about this point?

jhfozzy said:

Average current of a starter motor is about 300A+, that cable is rated at 70A. Nuff said.

And what about the cable already used in the car? from the manufacturer? its 4G multistrand cable. It's only rated at 70A. 300A is going to be 0G cable which is over an inch thick.

ETA: the current of the starter motor may be 300+A, thats not the amperage going to the motor through the cable. My high power boost pack is 90A max.

Edited by WorAl on Wednesday 3rd February 19:05

[jhfozzy]

WorAl said:

morebeanz said:

And what about this point?

jhfozzy said:

Average current of a starter motor is about 300A+, that cable is rated at 70A. Nuff said.

And what about the cable already used in the car? from the manufacturer? its 4G multistrand cable. It's only rated at 70A. 300A is going to be 0G cable which is over an inch thick.

ETA: the current of the starter motor may be 300+A, thats not the amperage going to the motor through the cable. My high power boost pack is 90A max.

That is the instantaneous current going to the starter via the cable, that's why the cables and starter get hot if kept cranking over for long periods.

The current will drop dramatically over the first couple of seconds, but only down to 100-200Amp depending on the useage.

The 4awg cable in the car as original equipment is good for about 100-150A, as it has good insulation properties i.e. heat resistance and used over a short run.

The maplins cable doesnt seem to have the same properties and as it is used for car audio will use cheaper insulation to cut costs, therefore limiting its current carrying capacity.

It's up to the OP, but I wouldn't use it, I'd get the right stuff marked for starter motor use.

[Marian]

jhfozzy said:

It's up to the OP, but I wouldn't use it, I'd get the right stuff marked for starter motor use.

Any links to where to get this?

[Nickccc]

http://www.demon-tweeks.co.uk/products/search.asp?...

[Marian]

Nickccc said:

http://www.demon-tweeks.co.uk/products/search.asp?...

Ta

[caduceus]

Thanks for the replies so far gents.
The meter tails look pretty substantial. I'm tempted to go with them.
That multi strand stuff doesn't seem to weather that well, and individual strands snap at the ends causing a gradual drop in current over time.

I might try and contact an electrical engineering company for some advice on what would be optimal for this application.

[morebeanz]

I don't know these guys, but they seem to have the appropriate gear...

http://www.autoelectrics.net/battery_cable.html