Welcome to the North American Subaru Impreza Owners Club Monday April 23, 2018
Home Forums WikiNASIOC Products Store Modifications Upgrade Garage
NASIOC
Go Back   NASIOC > NASIOC Technical > Electrical & Lighting

Welcome to NASIOC - The world's largest online community for Subaru enthusiasts!
Welcome to the NASIOC.com Subaru forum.

You are currently viewing our forum as a guest, which gives you limited access to view most discussions and access our other features. By joining our community, free of charge, you will have access to post topics, communicate privately with other members (PM), respond to polls, upload content and access many other special features. Registration is free, fast and simple, so please join our community today!

If you have any problems with the registration process or your account login, please contact us.
* Registered users of the site do not see these ads. 
Reply
 
Thread Tools Display Modes
Old 04-04-2018, 11:37 AM   #1
AudiobahnSTI
Scooby Specialist
 
Member#: 99339
Join Date: Oct 2005
Chapter/Region: MWSOC
Location: Edwardsville, IL
Vehicle:
04 STI
WRB

Default 04 sti alternator wiring

Iíve searched and searched but havenít found the info Iím looking for so figured I would start thread and try to get clean answer.
Well
I have a 2004 sti with the factory 3 pin alternator does anyone know what pin and wire color goes to what? I was thinking about wiring in a diode to one of the wires to trick the ecu into thinking there is not enough power and make the alternator charge. Iím just not sure what wire to use. Iíve read itís pin three which I think is blue wire but then Iíve read itís the blue/red wire which looks like it is pin 2. Anyone have a diagram of what wire goes to what?

My plan was to wire in dual pole switch that I can have the (correct wire) connected normal in one direction then when switched it will run through the diode. Anyone think it would work like I had planned it to? I was putting it on switch so donít always have to have it on constantly.
Any help would be greatly apperciated
Thanks
* Registered users of the site do not see these ads.
AudiobahnSTI is offline   Reply With Quote
Sponsored Links
* Registered users of the site do not see these ads.
Old 04-11-2018, 06:21 PM   #2
Cougar4
Scooby Guru
 
Member#: 53443
Join Date: Jan 2004
Location: Anchorage, AK
Vehicle:
2001 LL Bean Outback
Winestone

Default

The alternator and regulator is designed to charge the battery without an issue. Making the regulator charge the battery to more than it should could cause problems, particularly to the battery. Over charging it with higher charge voltage is a bad idea.
Cougar4 is offline   Reply With Quote
Old 04-16-2018, 02:35 PM   #3
AudiobahnSTI
Scooby Specialist
 
Member#: 99339
Join Date: Oct 2005
Chapter/Region: MWSOC
Location: Edwardsville, IL
Vehicle:
04 STI
WRB

Default

I put the diode in line on a switch so one way it runs normal and the other way it goes through diode normally it will runs 14.1 when itís switched it runs 14.7.
I understand it would be charging the battery to much at high voltage but there are times the voltage drops to around 12.8-13.2 well driving with everything on. I only use the switch when itís running lower then 13.4 with accessories on and I make sure to keep an eye on the voltage to the battery to make sure it donít go to high.
At cold start up I get 14.3
After warm it drops to about 13.5
With everything on and warm it will sometimes drop to 12.8
My volt gauge which is connected directly to battery is what I got those readings from. I have noticed that the accessport readings are normally slightly lower then the gauge.
AudiobahnSTI is offline   Reply With Quote
Old 04-17-2018, 11:50 AM   #4
Cougar4
Scooby Guru
 
Member#: 53443
Join Date: Jan 2004
Location: Anchorage, AK
Vehicle:
2001 LL Bean Outback
Winestone

Default

Well the voltages you stated for normal and higher charging rate are okay. I assume you have made sure the alternator belt isn't slipping and causing the lower charging voltages below 13 volts. As long as the battery voltage stays above 12.6 volts the battery is charging. Charging a battery at a lower charge rate is usually better for the battery life in the long term.

Having the input to the voltmeter at the battery is a good idea since wire losses and voltage drop across them will be minimized. It is fairly normal to have around a 1 volt difference between the battery voltage and the voltage at the dash panel due to wire losses.
Cougar4 is offline   Reply With Quote
Reply

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Forum Jump

All times are GMT -4. The time now is 11:04 PM.


Powered by vBulletin® Version 3.7.0
Copyright ©2000 - 2018, Jelsoft Enterprises Ltd.
Powered by Searchlight © 2018 Axivo Inc.
Copyright ©1999 - 2017, North American Subaru Impreza Owners Club, Inc.