Alternators again. I hate em.

Post by **RattyMcClelland** » Thu Oct 15, 2015 9:24 pm

Battery. Battery battery.

Post by **newkid** » Thu Oct 15, 2015 9:27 pm

Agree with ratty, battery has had it, this colder nights wont have helped much either.

Post by **RattyMcClelland** » Sun Nov 22, 2015 4:08 pm

SUCCESS!!!!!!!!!!!!!!!!!!!!!!

I got round to installing Newkids alternators from the S-spec he broke.

BOOM.

Charges fine and the battery light and cat light is off.

Also the numbers on the alt are different. The plug wiring has different letters and the regulators are different.
Ill uploads pictures later.

nitin_s1 · Post by **nitin_s1** » Sun Nov 22, 2015 4:50 pm

So the Jdm ones are different to the U.K. One ?

mercutio · Post by **mercutio** » Sun Nov 22, 2015 4:56 pm

must be

Post by **newkid** » Sun Nov 22, 2015 6:04 pm

Great news. Let's see the differences

Post by **RattyMcClelland** » Sun Nov 22, 2015 6:22 pm

5th gen Jdm left. 5th gen ukdm right

Jdm

UK

Notice the regulators are different and the wiring lettering on the bottom right diagram.

mercutio · Post by **mercutio** » Sun Nov 22, 2015 8:14 pm

and the Jdm one looks bigger might just be the angle though

Post by **RattyMcClelland** » Sun Nov 22, 2015 8:32 pm

Same size.

89 UKDM BA4 4WS (resto job!) · Post by **wurlycorner** » Sun Nov 22, 2015 10:40 pm

Interesting... Well spotted.
S means Sensor.
C is the local charge output.
The difference is whether the alternator regulator is intended to monitor local voltage, or the voltage actually at the battery.
If monitoring locally, the alternator picks up a feed straight from the main output post on the alternator (via a local link wire), so that pin is saying "i need to be connected directly to the main charge post". If using remote monitoring, it has an S terminal, so that pin is saying "I need to be connected to a wire straight back from the battery".
The principle of what happens inside the regulator is exactly the same, but because they are measuring at different points in the charge circuit on the car, I expect the regulator is probably 'tuned' differently?

Apparently the way you can test which set up your car is wired for, is to check for voltage on that pin (the S/C pin). If the car is set up to use an S alternator, so long as the battery is connected, there will always be voltage on the S pin on the plug. If the car is set up to use a C type alternator, it won't be, unless the alternator is running... (at least, that's what I've read, I must be honest that I can't understand why though,

because the main C output post is still connected to the battery positive terminal, so it should still be permanently live

)