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Battery Cable
Ian Pearson - 10/1/03 at 07:17 PM

Hi Guys,

I've a 2.0L Pinto with the original alternator. I've had to put the battery in the "BOOT", and as my electrical knowledge is almost as good as my mechanical, I have no idea what size cable I need to connect to the alternator. I haven't measured it yet, but would imagine that the run will be 7-8'. Any advice will be gratefully recieved.

Cheers for now, Ian.

stephen_gusterson - 10/1/03 at 08:25 PM

Its normal for a battery to have 3 things connected to it - a big cable to the starter, a big cable to the alternator, and a take off point, or points, for the normal car power.

You need to bring a cable forward from the battery to a point in the bonnet area where you can connect these things.


The alternator isnt the major current - its the starter.

Even a small resistance in the cable will have a major effect when you use the starter.

Lets say the cable resistance is 0.01 ohms at 400a starter current.

Thats 4 volts lost in the wiring!

Jaguar V12's and my 318 beemer have the battery in the back, as do many cars.

I would say use a cable size as large as you can sensibly go - certainly bigger than the std battery cable on the donor.


atb


Steve







[Edited on 10/1/03 by stephen_gusterson]

theconrodkid - 10/1/03 at 08:38 PM

just connect the alternator output wire to the starter motor terminal the battery cable goes to,use original type wire(thick) and you cant go wrong

Ian Pearson - 10/1/03 at 09:50 PM

Thanks John!!

stephen_gusterson - 10/1/03 at 11:06 PM

quote:
Originally posted by stephen_gusterson


You need to bring a cable forward from the battery to a point in the bonnet area where you can connect these things.


[Edited on 10/1/03 by stephen_gusterson]



Which of course could be the starter terminal itself



I should have made myself clearer. The alternator cable can be the same size as it always was. The important thing to remember is to bring the cable from the battery forward in a large size to the starter motor / common connection point - in order to avoid volts drop under starting conditions.

atb


steve


[Edited on 10/1/03 by stephen_gusterson]