Alternator Wiring Help

[11Budlite]

Thought I'd start a separate thread to help Hal with his alternator wiring. I'm sorry I couldn't remember the details at Carlisle, but I used the following info to wire my Geo alternator on the Birkin. Not sure what type of alternator the Caterham uses, but the wiring should be similar. Maybe some of you Caterham owners can jump in...

 

http://www.f1-rocketboy.com/alternator.htm

 

It's for an airplane, but I thought the description and drawing was pretty good.

 

Bruce :7drive:

[slngsht]

As I understood Harold's problem, the alternator drained the battery when the car was shut off. The first place to check is for voltage in the Ign switch lead (pin IG in Bruce's link).

[BobDrye]

As I understood Harold's problem, the alternator drained the battery when the car was shut off. The first place to check is for voltage in the Ign switch lead (pin IG in Bruce's link).

 

 

 

Hal said the the B+ wire from the alt goes to the starter which seems correct. I would check for power at the alt exciter terminal, which if prestant with the s/w off would drain the battery. If I were provided with a year and model Focus I could post a diagram.

 

 

:7head:

[slngsht]

Yup, I think we are saying the same thing. He also said he had no idea what the engine was out of.

[BobDrye]

Yup, I think we are saying the same thing. He also said he had no idea what the engine was out of.

 

I did a little research today and I found the following. Most newer Ford alts use 3 wires. 1 wire is to monitor the stator ripple voltage. The second wire turn the alt light on or off in the dash. The third wire is from the body control module to the exciter wire to the alt. You might say that the system has 2 voltage regulators. At certain times the body control module will decide to charge or not to charge the system. The alt will work just powering the exciter terminal thru the ign s/w.

 

Hopes this helps!

 

 

:7fume:

[EburgE]

Let me begin by saying, especially to Bob, I have never been so touched by a post on the Internet: to think that somebody would post my problem on a site just so that I'd get a solution is beyond words.:thumbs:

 

Actually, I have been disturbed for the past couple of weeks because I did not know where to turn with respect to the alternator questions.

 

Okay, enough gooey.

 

--Hal

 

 

[EburgE]

What I know:

 

1. The alternator is definately charging the batter when the engine is running. The B+ (big wire) is connected from the alternator to the starter to the battery.

 

2. When not running, unless I disconnect the B+ wire, the alternator drains the battery within a day or two.

 

3. The alternator has another connector--a THREE-PIN connector. I believe the three pins are connected to:

a. The battery via the ignition switch, i.e., the current is off when the key is off. Disconnecting this wire alone does NOT solve the drain problem.

b. The alternator light on the Tach. (This, by the way, is always illuminated when the ignition is on.)

c. The computer, i.e., the ECU which is a Pectel T2.

 

These connections sound consistent with Bob's findings, two posts above.

 

4. The alternator is a Bosch unit for a 2004 Ford Focus; the wiring harness is from Caterham. The engine is a 2004 from a Focus.

 

 

What I suspect:

 

1. The alternator could be the wrong model for the wiring harness. Caterham USA has not been able to provide a wiring diagram for the harness, nor can they tell me which year/model of Ford alternator the harness should use.

 

2. The alternator regulator (within the alternator) could be bad/damaged. Could this explain the drain on the battery?

 

3. The Pectel ECU could be set up wrong for the alternator? Not sure.

 

 

My next plan of action is to test each wire separately on the three-pin connector to see which, if any, are causing the battery to drain.

 

Any other ideas would be appreciated.

 

--Hal

[BobDrye]

What I know:

 

1. The alternator is definately charging the batter when the engine is running. The B+ (big wire) is connected from the alternator to the starter to the battery.

 

2. When not running, unless I disconnect the B+ wire, the alternator drains the battery within a day or two.

 

3. The alternator has another connector--a THREE-PIN connector. I believe the three pins are connected to:

a. The battery via the ignition switch, i.e., the current is off when the key is off. Disconnecting this wire alone does NOT solve the drain problem.

b. The alternator light on the Tach. (This, by the way, is always illuminated when the ignition is on.)

c. The computer, i.e., the ECU which is a Pectel T2.

 

These connections sound consistent with Bob's findings, two posts above.

 

4. The alternator is a Bosch unit for a 2004 Ford Focus; the wiring harness is from Caterham. The engine is a 2004 from a Focus.

 

 

What I suspect:

 

1. The alternator could be the wrong model for the wiring harness. Caterham USA has not been able to provide a wiring diagram for the harness, nor can they tell me which year/model of Ford alternator the harness should use.

 

2. The alternator regulator (within the alternator) could be bad/damaged. Could this explain the drain on the battery?

 

3. The Pectel ECU could be set up wrong for the alternator? Not sure.

 

 

My next plan of action is to test each wire separately on the three-pin connector to see which, if any, are causing the battery to drain.

 

Any other ideas would be appreciated.

 

--Hal

 

Hal:

The first wire that I would disconnect is the wire to the ECU. Then connect a test light in line with the battery positive. If the test light glows you have a drain. If not you have found the problem. The second procedure would be to disconnect the alt from the system. Does the test light still glow? If it does you still have a drain. If this is true start pulling fuses till the light goes out. If you connected an amp meter between the positive cable and the bat + you should see less than 50 mili amp. Most multi meters will allow up to 10 amps thru them. Do not turn anything on or you will probally blow the fuse in the meter.

 

 

 

:7head: :7head:

[jbanker]

Next option is to install a battery disconnect and forget it...That's what I did four years ago and it solved the problem.

 

Jack

[EburgE]

The folks at MidAtlantic Caterham have agreed to sort through the alternator, in addition to some other open issues. Will report back.

 

Thanks again!