Low voltage output from alternator
Pro
Joined: Aug 2001
Posts: 724
Likes: 0
From: West Palm Beach FL
you need to calculate pulley RPM's ..not engine RPM.....its not 1 to 1 ratio..............
Its not race provens "fault" ....even with the high output PTK alternator....the votage drops....I had the problem, NickYoskin does, Arnel does...........
Just make sure it is hooked up properly and drive it......We have all spent alot of time trying to figure out an alternative...
Its just the nature of the C5 and the small alternators we run....the Race proven unit is even smaller than the PTK unit...
Oh....Halltech was never able to get the voltage up either....and they spent alot of $$ trying to do so!
You need to get a PDF and get your alternator rpm up to where the alternator is making max output....it will be between 8000 and 16000 rpm....
Tom
Its not race provens "fault" ....even with the high output PTK alternator....the votage drops....I had the problem, NickYoskin does, Arnel does...........
Just make sure it is hooked up properly and drive it......We have all spent alot of time trying to figure out an alternative...
Its just the nature of the C5 and the small alternators we run....the Race proven unit is even smaller than the PTK unit...
Oh....Halltech was never able to get the voltage up either....and they spent alot of $$ trying to do so!
You need to get a PDF and get your alternator rpm up to where the alternator is making max output....it will be between 8000 and 16000 rpm....
Tom
Former Vendor
Joined: Nov 2005
Posts: 8,995
Likes: 2
From: Spring Texas
St. Jude Donor '08
Voltage at alternator with engine off was 12.9
Voltage when engine running at idle was 11.4
Voltage at 2500 rpm was 11.9
Voltage when I first started the car and drove to Advance auto Parts was 13.4 on the DIC. It stayed there for about 5 minutes then dropped to 12.4/12.2. This could be due to the battery starting to lose charge after I started running it. It was down to 11.5/11.7 while drove another 5 minutes. This is where it is at 2500 rpm unless I put the AC on and it drops to 11.2 volts. I'm putting another charge on it and checking the alternator terminal again. I can't imagine why Race Proven would sell me an alternator that I told them was going on my daily driver which is basically stock and that the only mod was the twin turbo.
I don't know of anyone driving around at 10,000 - 16,000 rpm's as Tom's earlier post alluded.
Would putting a larger pulley on the alternator make any improvement?
Voltage when engine running at idle was 11.4
Voltage at 2500 rpm was 11.9
Voltage when I first started the car and drove to Advance auto Parts was 13.4 on the DIC. It stayed there for about 5 minutes then dropped to 12.4/12.2. This could be due to the battery starting to lose charge after I started running it. It was down to 11.5/11.7 while drove another 5 minutes. This is where it is at 2500 rpm unless I put the AC on and it drops to 11.2 volts. I'm putting another charge on it and checking the alternator terminal again. I can't imagine why Race Proven would sell me an alternator that I told them was going on my daily driver which is basically stock and that the only mod was the twin turbo.
I don't know of anyone driving around at 10,000 - 16,000 rpm's as Tom's earlier post alluded.Would putting a larger pulley on the alternator make any improvement?
Thread Starter
Pro
Joined: Jul 2006
Posts: 675
Likes: 0
From: Punta Gorda FL A Man's got to know his limitations!
you need to calculate pulley RPM's ..not engine RPM.....its not 1 to 1 ratio..............
Its not race provens "fault" ....even with the high output PTK alternator....the votage drops....I had the problem, NickYoskin does, Arnel does...........
Just make sure it is hooked up properly and drive it......We have all spent alot of time trying to figure out an alternative...
Its just the nature of the C5 and the small alternators we run....the Race proven unit is even smaller than the PTK unit...
Oh....Halltech was never able to get the voltage up either....and they spent alot of $$ trying to do so!
You need to get a PDF and get your alternator rpm up to where the alternator is making max output....it will be between 8000 and 16000 rpm....
Tom
Its not race provens "fault" ....even with the high output PTK alternator....the votage drops....I had the problem, NickYoskin does, Arnel does...........
Just make sure it is hooked up properly and drive it......We have all spent alot of time trying to figure out an alternative...
Its just the nature of the C5 and the small alternators we run....the Race proven unit is even smaller than the PTK unit...
Oh....Halltech was never able to get the voltage up either....and they spent alot of $$ trying to do so!
You need to get a PDF and get your alternator rpm up to where the alternator is making max output....it will be between 8000 and 16000 rpm....
Tom
Thread Starter
Pro
Joined: Jul 2006
Posts: 675
Likes: 0
From: Punta Gorda FL A Man's got to know his limitations!
that's too low for any electrical system. Your system should never go below 12.0v at Idle. Usually the cause of such a voltage drop is excessive drain on your electrical system such as high powered audio equipment. I'd reccomend calling your local alternator shop ans seeing if they can't re-wire it.
Pro
Joined: Aug 2001
Posts: 724
Likes: 0
From: West Palm Beach FL
myself and Nick Yoskin have both had rewired alternators.....the space is just too small for a larger frame unit..
Race Proven can send you a file that gives the output vs RPM....you need to shoot for max output based on the PDF file....PDF is a type of file
Tom
Race Proven can send you a file that gives the output vs RPM....you need to shoot for max output based on the PDF file....PDF is a type of file
Tom
Thread Starter
Pro
Joined: Jul 2006
Posts: 675
Likes: 0
From: Punta Gorda FL A Man's got to know his limitations!
This would be helpful.
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Pro
Joined: Jan 2008
Posts: 675
Likes: 3
From: Riverside, California
on the whole "enough amperage thing" How many amps does a C5 require to operate?
Also why did some C5s come with the French 110 amp Valeo models and other got the mexican made 140 amp? Is there a difference in amperage requirements or was this simply seen as an upgrade through the years as having more power to play with?
Also why did some C5s come with the French 110 amp Valeo models and other got the mexican made 140 amp? Is there a difference in amperage requirements or was this simply seen as an upgrade through the years as having more power to play with?
Padrino
Former Vendor
Joined: Nov 2005
Posts: 8,995
Likes: 2
From: Spring Texas
St. Jude Donor '08
As far as total power output My best guess is that both systemss allow you to have between 30-60 extra amperes to play with depending on varying conditions (i.e. headlights running etc)
Le Mans Master
Joined: Sep 2000
Posts: 6,976
Likes: 527
From: Clouds Over California
I see 14.6 vdc at the back post of the Alternator and 14.1-14.2 @ startup and 13.8-14.0 once both fans kick in (operating temps). I also have an amplifier driving a 10" sub and dvd nav player.
I got my Alt tested at a Auto Electic shop with a load tester and they told me it was fine and then how to tell with it on the car running. First measure the vdc at the back of the alternator when you start the car up with a multimeter. If you get 14.4-14.6vdc at the back post of the alternator...where the battery terminal hooks up...your alternator is working fine. The difference between the post (back of alt) and what you see on the DIC is the voltage drop across the harness. Even when I didn't have my alternator wired correctly the lowest I ever saw on the DIC (at night, AC, fans, stereo, lights on) was 12.0 vdc.
Haven't had the problem and have posted the wiring diagrams before on this forum.
Here is the PM discussion with Bill before I wired it up correctly.Private Message: Re: Alternator Wiring Connector
Recipients: Bill Dearborn
12-18-2007, 12:28 PM
Shinobi'sZ
CF Senior Member
Member Since: Sep 2000
Location: Many places at once in Kalifornia Re: Alternator Wiring Connector
--------------------------------------------------------------------------------
Quote:
Originally Posted by Bill Dearborn
I went to the Service Manual and assembled the following info. It is for all 2000 and newer C5s. The description tells you what the wires are for and the schematic shows how they are attached.
Bill
Quote:
Originally Posted by Shinobi'sZ
Hi Bill,
Since you are the resident electrical guy I thought I would pose another gremlin question to you...as long as you don't mind.
I am trying to indentify the wires on my Alternator wiring harness. There is a big red wire that has a constant 12vdc non switched. Then a thin red wire that only comes on when switched...however it doesn't read the same vdc as the other...it is always about 2 vdc lower. Then there is a grey wire...I am trying to identify each wire and determine what it does for the Alternator.
I have been running a single wire to an aftermarket alternator..but I just run the wire from the fuse box 12vdc switched to the ALt. I was thinking if I could figure out what the wires are in the OEM harness that go to the OEM alternator..that I could just tap into them.
Thanks.
Just want to say thanks for all of your help. My Alternator now reads 14.1 almost all of the time on the DIC.
Also I replaced my SWPS and it resolved the 1287, 1288 code and Service Active Handling codes.
Shinobi'sZ
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Last edited by Shinobi'sZ; May 17, 2008 at 06:00 PM.
Advanced
Joined: Jun 2007
Posts: 90
Likes: 0
From: Knoxville Tennessee
Bill
I think the twin turbo design wasnt thought through....the space where the alternator sits...upper passenger side....is space limited so the smallest alternator on the market was chosen.
I spoke to all the PTK guys...all complained of low voltage...yet none of us ever had a problem maintaining power to any accessory. This is real world testing....by multiple people......cant get better than that..
Also the ND model alternators are made for race teams that run high rpms....these things need to run at 10,000 rpm (based on pulley size) for one to get them to voltage /AMP output and for cooling purposes (this from the Race Proven builders....in Georgia and Germany).....they know alternators.....
Keep in mind we are not talking about a direct drivers side alternator replacement here is my setup....ND150 (160 amp output at 280 degrees and 16,000 rpm)...havent run the motor with this alternator...yet..
Tom
Tom
I think the twin turbo design wasnt thought through....the space where the alternator sits...upper passenger side....is space limited so the smallest alternator on the market was chosen.
I spoke to all the PTK guys...all complained of low voltage...yet none of us ever had a problem maintaining power to any accessory. This is real world testing....by multiple people......cant get better than that..
Also the ND model alternators are made for race teams that run high rpms....these things need to run at 10,000 rpm (based on pulley size) for one to get them to voltage /AMP output and for cooling purposes (this from the Race Proven builders....in Georgia and Germany).....they know alternators.....
Keep in mind we are not talking about a direct drivers side alternator replacement here is my setup....ND150 (160 amp output at 280 degrees and 16,000 rpm)...havent run the motor with this alternator...yet..
Tom
Tom
can you give me a call at 501-258-3704 about this alternator bracket.
Tech Contributor
Joined: Dec 1999
Posts: 32,910
Likes: 2,402
From: Anthony TX
CI 6,7,8,9,11 Vet
St. Jude Donor '08
Voltage at alternator with engine off was 12.9
Voltage when engine running at idle was 11.4
Voltage at 2500 rpm was 11.9
Voltage when I first started the car and drove to Advance auto Parts was 13.4 on the DIC. It stayed there for about 5 minutes then dropped to 12.4/12.2. This could be due to the battery starting to lose charge after I started running it. It was down to 11.5/11.7 while drove another 5 minutes. This is where it is at 2500 rpm unless I put the AC on and it drops to 11.2 volts. I'm putting another charge on it and checking the alternator terminal again. I can't imagine why Race Proven would sell me an alternator that I told them was going on my daily driver which is basically stock and that the only mod was the twin turbo. I don't know of anyone driving around at 10,000 - 16,000 rpm's as Tom's earlier post alluded.
Would putting a larger pulley on the alternator make any improvement?
Voltage when engine running at idle was 11.4
Voltage at 2500 rpm was 11.9
Voltage when I first started the car and drove to Advance auto Parts was 13.4 on the DIC. It stayed there for about 5 minutes then dropped to 12.4/12.2. This could be due to the battery starting to lose charge after I started running it. It was down to 11.5/11.7 while drove another 5 minutes. This is where it is at 2500 rpm unless I put the AC on and it drops to 11.2 volts. I'm putting another charge on it and checking the alternator terminal again. I can't imagine why Race Proven would sell me an alternator that I told them was going on my daily driver which is basically stock and that the only mod was the twin turbo.
I don't know of anyone driving around at 10,000 - 16,000 rpm's as Tom's earlier post alluded.Would putting a larger pulley on the alternator make any improvement?
Your alternator is NOT charging. Can you post up a schematic for the terminal lay out of that alternator?? Then I can give you guidane on what you chould have voltage wise on all the terminals.
Bil
