AE86 16V - Alternator Wiring Basics...

User avatar
jondee86
Moderator
Posts: 2319
Joined: Fri Jan 11, 2013 10:21 pm
Location: Wellington, New Zealand

AE86 16V - Alternator Wiring Basics...

Postby jondee86 » Sun May 04, 2014 9:37 pm

Here is a Toyota schematic of the AE86 alternator wiring...

Image

The alternator has four wires labelled S, L, IG and B.

S is the "Sense" wire that tells the regulator battery voltage, so that
it can adjust the charging rate. Flat battery - high rate, full battery = low rate.

L is for the charge indicator light. When the alternator is charging, the
voltage on this wire cancels the charge warning light.

IG is a switched supply from the battery to provide the initial kick (excitation)
to make sure that the alternator starts generating when the engine starts.

B is the battery wire. This is the heavy wire that connects the alternator to
the battery, and carries the full charging current.

Here are the terminal identifications for the round plug...

Image


So what happens when you connect the battery backwards ?

Well, the alternator is connected directly to the battery positive at all times,
and the rectifier diodes prevent any current flowing back thru the alternator to
ground. When you connect the battery in reverse, battery voltage is applied to
the alternator in the reverse direction, and the diodes (being one-way devices)
cannot block the flow.

Thus, a high current short circuit occurs thru the alternator. If you are lucky
the fusible link will blow before the alternator is destroyed :)

Cheers... jondee86
Give a person a fish, they eat for a day. Suggest they search before posting, and they learn a skill for a lifetime.

Disable adblock

This site is supported by ads and donations.
If you see this text you are blocking our ads.
Please consider a Donation to support the site.


User avatar
ToeKnee805
Club4AG Expert
Posts: 299
Joined: Wed Jan 09, 2013 8:17 pm
Location: Southern California, 805

Re: AE86 16V - Alternator Wiring Basics...

Postby ToeKnee805 » Tue Feb 10, 2015 8:52 pm

damn this post gets no credit!

About to swap a 16v to my TE72 and definitely bookmarking this. Thanks for the info!
1986 Corolla GT-S -- Unmolested -- Now Resto Project
1985 Corolla GT-S -- Turbo Levin Track Car
1982 Corolla 1.8 -- Sitting collecting dust

User avatar
jondee86
Moderator
Posts: 2319
Joined: Fri Jan 11, 2013 10:21 pm
Location: Wellington, New Zealand

Re: AE86 16V - Alternator Wiring Basics...

Postby jondee86 » Thu Feb 12, 2015 12:34 am

Thanks dude !! It's nice to know that someone actually reads these
writeups and finds them useful. Good luck with your engine swap :)

Cheers... jondee86
Give a person a fish, they eat for a day. Suggest they search before posting, and they learn a skill for a lifetime.

User avatar
gotzoom?
Club4AG Expert
Posts: 403
Joined: Fri Jan 11, 2013 8:42 am
Location: Silicon Valley, CA
Contact:

Re: AE86 16V - Alternator Wiring Basics...

Postby gotzoom? » Thu Feb 12, 2015 9:54 am

Be sure the contacts in the round connector and on the alternator are clean when you plug the connector in. Many people replace "bad" alternators that really just have dirty contacts.

Disable adblock

This site is supported by ads and donations.
If you see this text you are blocking our ads.
Please consider a Donation to support the site.


tlea
Club4AG Regular
Posts: 20
Joined: Fri Aug 03, 2018 3:34 am

Re: AE86 16V - Alternator Wiring Basics...

Postby tlea » Mon Sep 17, 2018 11:08 am

Great diagram. I am putting 20V in non Toyota chassis so couple of questions
B= Battery, got this,. Direct charging return to battery
IG= switched ignition source, got it
L= Here comes questions. Does this go to light that has other side to switched voltage?
S= Just battery voltage? Would seem if just connected to positve terminal would read charging voltage?
Thanks

User avatar
jondee86
Moderator
Posts: 2319
Joined: Fri Jan 11, 2013 10:21 pm
Location: Wellington, New Zealand

Re: AE86 16V - Alternator Wiring Basics...

Postby jondee86 » Mon Sep 17, 2018 3:10 pm

tlea wrote:L= Does this go to light that has other side to switched voltage?

Since you have a 4AGE you can ignore the charge relay, the wire marked 4AC
and the ground connection. All you are left is a loop between the Ignition and
charge fuses. The Charge fuse has no voltage until the engine is running.

I have to assume that the regulator provides a ground path to enable the
charge warning light when the ignition is turned ON but the engine is not
running. Then, when the engine is started 12V is applied to both sides of
the light and it turns OFF.

S= Just battery voltage?

The regulator uses the Sense wire to monitor battery voltage. As its name
implies, it regulates the charge current according to the sensed voltage. If
the battery is fully charged (around 14.2V), charging current will be regulated
down to almost zero. If the battery is low or if there is a heavy current drain
from accessories, charging current will be increased.

If you like, the Sense wire is used to create a feedback loop to allow charge
current regulation based on the state of charge :)

Cheers... jondee86
Give a person a fish, they eat for a day. Suggest they search before posting, and they learn a skill for a lifetime.

tlea
Club4AG Regular
Posts: 20
Joined: Fri Aug 03, 2018 3:34 am

Re: AE86 16V - Alternator Wiring Basics...

Postby tlea » Mon Sep 17, 2018 3:41 pm

Got it. I I understand what you’re saying but I’m still trying to have a practical application for mine. There will be no charge light unless I provide one. I’m thinking of a normal white that there is a power contact and then a ground contact. I’m not sure what type of light has two power connections to make it go off and less it has a relay?
On the sense wire Would it then just connect to the positive terminal of the battery same as the charge wire?

User avatar
jondee86
Moderator
Posts: 2319
Joined: Fri Jan 11, 2013 10:21 pm
Location: Wellington, New Zealand

Re: AE86 16V - Alternator Wiring Basics...

Postby jondee86 » Tue Sep 18, 2018 1:03 am

If you take a wire from an ignition switched source to the Charge Warning Light
(whick incorporates a diode, so is polarity sensitive), and then from the CWL to
the Charge Indicator Light output on the alternator, it will work. The regulator
provides a path to ground when the ignition is switched ON. When the engine is
started the alternator applies 12V to the CIL wire and the light now has 12V on
both sides so that no current flows and the light goes out.

The CWL is usually a 4Watt incandescent bulb and I expect that you could find
something suitable in the dash of just about any old Japanese car in a junkyard.
Just be aware that not all alternators have a separate IG wire, and some use
the CWL circuit to double as a 12V supply to provide the initial excitation to
start the alternator charging. So check for a 4-wire alternator if looking for a
CWL in the junkyard.

You can achieve the same result with a relay, and that is often the way it was
done when the alternator had an external regulator e.g. as shown in the abobe
diagram for use with the 4AC engine AE86.

The sense wire needs to connect as close to the positive battery terminal as is
reasonably possible. Any resistance between the point of connection and the
battery terminal will affect the voltage sensed by the regulator.

Cheers... jondee86
Give a person a fish, they eat for a day. Suggest they search before posting, and they learn a skill for a lifetime.

tlea
Club4AG Regular
Posts: 20
Joined: Fri Aug 03, 2018 3:34 am

Re: AE86 16V - Alternator Wiring Basics...

Postby tlea » Tue Sep 18, 2018 4:33 am

excellent explanation. Thank you

Disable adblock

This site is supported by ads and donations.
If you see this text you are blocking our ads.
Please consider a Donation to support the site.



Return to “TECH: Corolla AE86”

Who is online

Users browsing this forum: No registered users and 0 guests