Alternator main cable size (mm^2) for new eyelet?
Alternator main cable size (mm^2) for new eyelet?
Author
Discussion

ben2083

Original Poster:

43 posts

178 months

Monday 7th December 2015
quotequote all
Hi,

I managed to shear my alternator cable eyelet off the end of the cable at the weekend when swapping the alternator over. Need to order a new eyelet to crimp on to the cable but not sure what size the cable in, in cross sectional area, anybody know? The stub on the alternator is M8, so need an 8mm hole but what size cable to accept.....it's a '99 Serp engine if that helps!

Thanks in advance.

phillpot

17,510 posts

212 months

Monday 7th December 2015
quotequote all
If you're going to use the type with coloured insulation it's a yellow one you want


If you prefer this type (solder on?) 6 x 8 should do the trick I think.



Of course you could just strip the end of the cable and squash between two flat washers ...... getmecoat

ben2083

Original Poster:

43 posts

178 months

Monday 7th December 2015
quotequote all

Thanks for the swift response.

6mm squared for the main 12v feed....glad I asked, I would have guessed at much more. Will order some and see, it's not going to break the bank anyway!

ukdj

1,004 posts

213 months

Monday 7th December 2015
quotequote all
Those size connectors are for the switched feed to the starter solenoid NOT the main direct feed to the battery/alternator.

Alan461

853 posts

160 months

Monday 7th December 2015
quotequote all
Mine had 16sq mm but changed it for 35sq mm
I used an eyelet for welding cable which was much more robust than standard

phillpot

17,510 posts

212 months

Monday 7th December 2015
quotequote all


Bit of confusion here?

ben2083 said:
I managed to shear my alternator cable eyelet off
I thought we were talking the power feed from the back of the alternator (same as 100 amp fuse) not the main battery to starter feed?

ukdj said:
Those size connectors are for the switched feed to the starter solenoid NOT the main direct feed to the battery/alternator.

ben2083

Original Poster:

43 posts

178 months

Tuesday 8th December 2015
quotequote all
Ok, now I am confused too!

The cable I am talking about is the main connector on the back of the alternator, it's a brown cable on mine. It has (or rather had!) an eyelet on the end which connects to the largest stud on the alternator with an M8 nut.


ukdj

1,004 posts

213 months

Tuesday 8th December 2015
quotequote all
Ahh my bad I think, got my wires crossed ;-)

Although the yellow eyelet connectors are usually only rated to around 30amps so whilst they might be the correct size, they probably aren't the correct rating for the alternator output, which depending on alternator model and running load can output anything up to 100amp.

phillpot

17,510 posts

212 months

Tuesday 8th December 2015
quotequote all


ideally a photo might clear up the confusion but failing that can you measure (or at least estimate) the overall diameter of the wire in question, including the insulation?

thicker/thinner than a pencil?

ukdj

1,004 posts

213 months

Tuesday 8th December 2015
quotequote all
Here's a dead crispy one i replaced earlier ....


ben2083

Original Poster:

43 posts

178 months

Tuesday 8th December 2015
quotequote all
Unfortunately I won't get a chance to measure, or get a photo, till the weekend, at which point I can calculate the CSA myself.Just thought I'd ask in case anyone had any experience so that I could order eyelets in advance, ready for the weekend.

If I was to estimate I would think it was a similar diameter to a pencil, so about 6mm, which would led to a CSA of ~30mm Squared? I think it was a single wire though rather than the two shown in ukdj's photo.

Probably best I wait till the weekend, measure it properly and pop to Halfrauds for a new one.

Thanks for your help though.

FoxTVR430

452 posts

140 months

Tuesday 8th December 2015
quotequote all
ukdj said:
Here's a dead crispy one i replaced earlier ....

That looks more like speaker wire yikes

ukdj

1,004 posts

213 months

Tuesday 8th December 2015
quotequote all
FoxTVR430 said:
That looks more like speaker wire yikes
TVR original spec, shocking I know! Obviously this grade of wire was on special offer during build time

Now replaced with something a bit more substantial

QBee

22,464 posts

173 months

Wednesday 9th December 2015
quotequote all
6mm cable is indeed about 30 square millimetres - the formula you are groping for is Pie arrrrgh squared, ie Pie x 3 x 3 = 28.27 sq mm.

chimp427

11,871 posts

262 months

Wednesday 9th December 2015
quotequote all
pm me your details and i will post you a few eyelets covering 4 mm to 25 mm with an 8mm hole.
You will need a good set of ratchet crimpers or similar to make a decent job of it though.

Mr Jenks

1,207 posts

294 months

Mr Jenks

1,207 posts

294 months

Wednesday 9th December 2015
quotequote all
chimp427 said:
You will need a good set of ratchet crimpers or similar to make a decent job of it though.
I got these to do my battery cables and alternator cable.
https://www.tlc-direct.co.uk/Products/SWRP625.html