Alternator swap.

Post by **shepster** » 11 Jul 2007, 13:27

I have a 45amp plug in type alternator and have bought a 90 amp 'post' type one, can i simply modify the wiring or have i dropped a b*****k?

Post by **R0B** » 11 Jul 2007, 14:13

i have gone from post type to plug in before.so i dont see why not.assuming its ok to go from 45 to 90 amp....

Post by **Ian Hulley** » 11 Jul 2007, 14:29

Knock up a micro loom (out of the same thickness of cable) to adapt from one to the other. I've 2 90 amp alt.s one of each

so I have the adaptor loom fitted to the spare I carry on the big trips.

Cheers,Ian.

Post by **shepster** » 11 Jul 2007, 14:58

So do i simply attach the two thick wires to the thick post and the thin one to the thinner post?

Post by **lloyd** » 11 Jul 2007, 15:16

Does van wired with 45 amp alternator have big enough wire to handle 90 amp alternator? 90 amp needs bigger wiring then 45 amp. Not sure but think wire amp vs wire size is something like this:
45 amp needs 8mm wire for 4' and 19mm for long runs.
90 amp needs 19mm for 4' and 30mm for long runs.
Runs being distance from alternator to battery.

Post by **shepster** » 11 Jul 2007, 15:28

lloyd wrote:Does van wired with 45 amp alternator have big enough wire to handle 90 amp alternator? 90 amp needs bigger wiring then 45 amp. Not sure but think wire amp vs wire size is something like this:
45 amp needs 8mm wire for 4' and 19mm for long runs.
90 amp needs 19mm for 4' and 30mm for long runs.
Runs being distance from alternator to battery.

30mm cable! f**k me the van would be worth more weighed in! are you sure you have that right as i haven't seen anything that thick anywhere.

Post by **lloyd** » 11 Jul 2007, 15:41

Sounded to big to me too. Thing is 90amp requires bigger wiring then 45amp.

Found this link showing it it gauge wire size: http://www.the12volt.com/info/recwirsz.asp

And this one to convert size: http://www.rbeelectronics.com/wtable.htm

I'm not sure of this, but I do know when I've change to bigger alternators on rigs in the past, I had to use bigger wire from alternator to battery.

Still searching for more info

Post by **lloyd** » 11 Jul 2007, 15:54

Here's a good chart of wire size for amps and length of wire: http://www.motorcityreman.com/technical-info.html

I'm sure others have installed bigger alternators and will be along to help figure this out. Seem s somewhere i saw a write-up on wiring a t3, but can't seem to find it now.

Post by **shepster** » 12 Jul 2007, 07:45

sukhoi27 wrote:i have gone from post type to plug in before.so i dont see why not.assuming its ok to go from 45 to 90 amp....

Which wires go where then Rob?......

Post by **billy739** » 12 Jul 2007, 08:01

did this conversion no probs!
i think all vans are wired for 90 amp,as from all i have broken up they all have the same size wire front/back weather 2.0l Aircooled 1.9dg or 2.1 engine!
never had a problem,join the two thicker wires with a loop terminal and another smaller on the blue wire!
easy

Post by **shepster** » 12 Jul 2007, 08:19

Cheers Billy!

Post by **R0B** » 12 Jul 2007, 11:19

sorry cant answer that.mocki did mine.....

Which wires go where then Rob?

Post by **shepster** » 16 Jul 2007, 09:53

Now fitted and working, as Billy said simply crimp two connectors to the fat wires and bolt them to the fat pin and the same with the thinner wire and connect that to the thin pin.

Cheers.