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Alternator wiring Options
tims31 - 17/3/14 at 11:02 AM

Can someone please take a look at the diagram below and let me know if there is any real difference to the two options when it comes to wiring up my alternator.

The plan is to have the battery on the right of my car so the layout is as it will be installed but I just wanted to check that Option 1 is the easiest way for me to do it and option two is the usual way of doing it but to my eyes its the same, am I correct and is it ok to do it as per option 1?


Description
Description

Thanks

DW100 - 17/3/14 at 11:21 AM

Or option 3, Run both wires to the battery.

Option 2 is more usual as the wire between the alternator and the battery is not normally as heavy gauge as the one going to the starter.

r1_pete - 17/3/14 at 11:22 AM

I'd go with option 2, keeps the battery to starter cable shortest, and involves fewer connections in the high current circuit.

SteveWalker - 17/3/14 at 11:25 AM

I'd go for option 2. It reduces resistance and possibilities of poor connections to the starter and also means that you've not got a high starting current flowing at the alternator connection - many just have a plug-in connector unsuitable for starter loads.

Pahhh - you pause for a moment to answer a phonecall and find that two people have answered before you!

[Edited on 17/3/14 by SteveWalker]

tims31 - 17/3/14 at 11:30 AM

Great, guess i'll go with option two.

What size cables should I be using for the two runs, the alternator is a 40amp and the starter is from a CVH mounted on a Zetec? Flexible cable preferably

britishtrident - 17/3/14 at 12:04 PM

Option (1) increases the potential for a wiring fire because the event of a problem or error with the main battery to starter cable you could end with a situation where full starter current is flowing through the alternator wires.

Either use option (2) which is perfectly adequate or wire straight from the alternator to the battery or fuse box.

r1_pete - 17/3/14 at 02:52 PM

quote:
Originally posted by tims31
Great, guess i'll go with option two.

What size cables should I be using for the two runs, the alternator is a 40amp and the starter is from a CVH mounted on a Zetec? Flexible cable preferably


Have a look on Vehicle Wiring Products site, they list all sizes of cable, current rating etc, I'd go for 60 amp for the alternator, and welder cable for the starter as its so flexible, VWP list this too.

tims31 - 17/3/14 at 03:24 PM

Thanks very much to all for your help

[Edited on 17/3/14 by tims31]