90 amp alternator

[jeffdub]

hi all ive just got hold of a 90 amp alternator and noticed that it has 2 bolt connections on the rear where my old one had 3 spade connections could someone give me an idea where my 2 red wires and the blue one fit please ? thank you jeff

[DentedDevon]

The 2 red wires go to the large terminal with the 13mm nut,the thin blue wire goes to the small terminal.
Make sure all the connections going back to the battery are clean and tight, including the earth straps on the gearbox and on the battery.
I ended up having to fit a new earth strap on my battey because the old one was losing me nearly 1 volt.
To benefit from the 90 amp output I would upgrade the 2 red wires to something heavier , they run to the battery terminal on the starter motor.

[jeffdub]

thanks richard what size wire would you recommend ?

[kevtherev]

thanks richard what size wire would you recommend ?

thicker the better Jeff
So anything over 8mm

E D I T... meant to say 6mm

[jeffdub]

thanks kev

[jeffdub]

just had a quick look on ebay and cant find anything that thick ?

[kevtherev]

You're better off going to an electrical supplies outlet Jeff.
Like Edmundson, CEF, Wilts, Newey and Eyre etc

tell them what amperage (up to 50A DC ) your using, and they will supply the correct cable

[jeffdub]

cheers kev i'll do that

[California Dreamin]

You need to rate to the max output (90amps) although this sort of charge is rare and most of it's life the alternator will be sat delivering 15 - 20 amps to keep up with the lights etc.

http://www.autoelectricsupplies.co.uk/p ... tegory/124" onclick="window.open(this.href);return false;

Martin

[DentedDevon]

Just been checking wiring diagrams.
There are at least 2 variations of the alternator wiring. Some are wired direct to the startermotor and some via the engine bay junction box.
The original wiring totals either 5 or 6 mm2 (square mm).
I think the plug type alternators are usually 45 amps, so you are doubling the potential output.
If you fit an EXTRA cable from the alternator to the starter motor battery terminal that is 6 or 8 mm2 you will have doubled the current carrying capacity.
As California Dreaming rightly says it will be rare for the full 90 amps to be needed. However the heavier cable is important to keep voltage drop down when the system is under load.
(try putting a volt meter on your battery with the engine running then watch what happens as you switch everything on)
CAUTION ... Disconnect the battery before starting work, make sure the new cable is secure and protected where necessary - there are no fuses protecting this part of the system !

[California Dreamin]

DentedDevon's suggestion of ADDING an extra wire similar in gauge to the existing one is a good idea....there is usually plenty of thread on both the aternators main post and the starter solenoid...just be careful to properly fix the terminals (personally I would solder them) and insulate them so there is no risk of shorting (sleave shrink)

Martin

[jeffdub]

thanks for the advice lads but you have to bear in mind im a bit thick when it comes to electrics

[jeffdub]

i think both of my red wires go to the starter motor so where do i add an extra wire from ?

[jeffdub]

thank you for the link california which one would i need ?

[DentedDevon]

i think both of my red wires go to the starter motor so where do i add an extra wire from ?

Make the new wire follow the same route as the existing ones and connect to the same terminal at each end as well.