Ammeter shows ( -14 )
Thread Starter
Instructor
Joined: Aug 2009
Posts: 147
Likes: 2
From: Colorado Springs Colorado
Ammeter shows ( -14 )
After noting that my headlights/dashlight/ any electronics would dim considerably at a stop or idle. Hell if I hit the brights, my radio shuts off. So I decided hell why not do an alternator upgrade, after reading on the forums and looking through a few other sites I decided on the CS144.
Got it from QualityPower (ebay seller, they have a website as well). After many trips to Home Depot for various bolts, nuts hardware, wire crimper and such its finally in. The Previous owner must of have some kind of problem with the alternator before as he had some quick disconnects for the alt, I cut those off put on new ends, ran the adapter, made sure everything was aligned and started her up.
No real problems noted, although I didn't run the 10ga to the starter as Durango_Boy's instructions advised but..... My ammeter is showing negative and I can still dim the hell out of my lights, any ideas?
Got it from QualityPower (ebay seller, they have a website as well). After many trips to Home Depot for various bolts, nuts hardware, wire crimper and such its finally in. The Previous owner must of have some kind of problem with the alternator before as he had some quick disconnects for the alt, I cut those off put on new ends, ran the adapter, made sure everything was aligned and started her up.
No real problems noted, although I didn't run the 10ga to the starter as Durango_Boy's instructions advised but..... My ammeter is showing negative and I can still dim the hell out of my lights, any ideas?
Racer
Joined: Dec 2009
Posts: 380
Likes: 0
From: Glendale AZ
I would start by adding the extra current path for your alternator to the starter lug (which in turn feeds the main positive connection directly)
Dimming of the headlights is fairly normal with the way the electrical system was designed. Unlike many modern cars, the headlights are powered by dash voltage which is usually diminished.
The cure for dimming headlights is to feed them off the alternator hot directly via relays which eliminates the voltage drop that you are seeing.
I wouldn't sweat the amneter too much as they're hard to make work correctly after changing the charging system to higher capacity. What's more important is your voltage at the alternator and at the battery.
Dimming of the headlights is fairly normal with the way the electrical system was designed. Unlike many modern cars, the headlights are powered by dash voltage which is usually diminished.
The cure for dimming headlights is to feed them off the alternator hot directly via relays which eliminates the voltage drop that you are seeing.
I wouldn't sweat the amneter too much as they're hard to make work correctly after changing the charging system to higher capacity. What's more important is your voltage at the alternator and at the battery.
Last edited by volition; Dec 30, 2009 at 12:23 AM.
Race Director
Joined: Sep 2002
Posts: 10,362
Likes: 5
From: San Diego - Deep Within The State of CONFUSION!
If you are showing a discharge, it is discharging. Unless something is not wired properly.
Racer
Joined: Dec 2009
Posts: 380
Likes: 0
From: Glendale AZ
I respectfully disagree completely. If the alternator is functioning properly and it's connected right, the ammeter should be showing a charge. Regardless of it being a higher-amp unit than the car came with.
If you are showing a discharge, it is discharging. Unless something is not wired properly.
If you are showing a discharge, it is discharging. Unless something is not wired properly.
Diagnosing whether it's charging or not using the factory ammeter alone isn't really reliable enough depending on what wiring modifications were done to accomodate the CS144.
If left alone a negative on the ammeter does indeed show a drain (non-charge). Either way to verify the system is working correctly;
We need to measure voltage and its drop to see if the alternator is:
#1)Recieving a signal on the exciter wire
#2)Sensing battery voltage correctly on the S terminal
Which adapter did you use for the conversion and did you add the resistor in?
Last edited by volition; Dec 30, 2009 at 12:51 AM.
Thread Starter
Instructor
Joined: Aug 2009
Posts: 147
Likes: 2
From: Colorado Springs Colorado
looks like I have a few things to do this weekend, I'll add the wire to the starter, check all my crimps for the connectors and check voltages. The guy who sold me the adapter said I didn't need the resistor because it was built-in already on my car (1975) I have the idiot lights for headlight and brake, but I never seen the other 2 light up so I don't know what they are.
I'll pick up the napa adapter with the resistor built-in to that and try again I suppose. I'll keep you guys posted.
I'll pick up the napa adapter with the resistor built-in to that and try again I suppose. I'll keep you guys posted.
Burning Brakes
Joined: Jan 2006
Posts: 1,223
Likes: 174
From: Fort Wayne IN
I do not think you have an alt idiot light in your car
Racer
Joined: Dec 2009
Posts: 380
Likes: 0
From: Glendale AZ
looks like I have a few things to do this weekend, I'll add the wire to the starter, check all my crimps for the connectors and check voltages. The guy who sold me the adapter said I didn't need the resistor because it was built-in already on my car (1975) I have the idiot lights for headlight and brake, but I never seen the other 2 light up so I don't know what they are.
I'll pick up the napa adapter with the resistor built-in to that and try again I suppose. I'll keep you guys posted.
I'll pick up the napa adapter with the resistor built-in to that and try again I suppose. I'll keep you guys posted.
This is likely the cause of your drain that your ammeter is showing.
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Le Mans Master
Joined: Dec 2007
Posts: 6,422
Likes: 591
From: McHenry Illinois
Your 75 does not have a gen light, so you will need the resister, but it's purpose is to protect the alternator. As others have said, go ahead and install the heavier wire from the alternator to the battery terminal of the starter and then check the voltage at the alternator and then at the battery. Also check the voltage at the alternator and battery with your lights on and try to see where you are loosing the voltage. Does the ammeter go th the center when the car and all accessories are off?
Le Mans Master
Joined: Jan 2001
Posts: 6,743
Likes: 1,385
How to determine what CS-144 adapter you need
Here's what I did to figure what adapter I needed. Worked perfect the first time I hooked it up.
You can do the quick check below to see what adapter you need to convert from 12si to CS-144 ...then go to the local parts store and get the equivalent part (I went to NAPA, mine took Echlin part # EC82).
"If you are unsure which adapter to use, measure the resistance of the exciter line. Disconnect the positive battery cable and the alternator plug. Connect an ohm meter between the #1 terminal on the plug end of the alternator harness and the end of the positive battery cable. Turn the ignition key to the "on" position and read the ohmmeter. If resistance is less than 35 ohms, use adapter #8078. If it’s between 35-350 ohms, use #8077. If it’s more than 350 ohms, you have excessive resistance somewhere in that circuit which needs to be repaired, first."
...the above text is from:
http://www.netmotive.net/articles/hib/reman.html
that's the guidelines I used to wire mine in and it worked from the get-go.
I got my CS-144 at the junkyard for 22 bucks; it cost me more for the electrical adapter and the belt........it turned out to be a 140 amp unit....goofy one with a third ear; I only bought it to see if I could make it fit...and then it turns out to be in great shape...I lopped off the 3rd ear; as you can see the other 2 bolt holes are 180° apart.
You can see it bolted on - see my corvette photos here: https://www.corvetteforum.com/g/picture/6185141
AC delco part number 321-1144...
you can here to see the image, and you can search by ac delco part numbers in rockauto (if you have different part number also):
https://www.rockauto.com/en/moreinfo...sn=267&jsn=267
according to the napa website it's a 140 amp alternator.
You can do the quick check below to see what adapter you need to convert from 12si to CS-144 ...then go to the local parts store and get the equivalent part (I went to NAPA, mine took Echlin part # EC82).
"If you are unsure which adapter to use, measure the resistance of the exciter line. Disconnect the positive battery cable and the alternator plug. Connect an ohm meter between the #1 terminal on the plug end of the alternator harness and the end of the positive battery cable. Turn the ignition key to the "on" position and read the ohmmeter. If resistance is less than 35 ohms, use adapter #8078. If it’s between 35-350 ohms, use #8077. If it’s more than 350 ohms, you have excessive resistance somewhere in that circuit which needs to be repaired, first."
...the above text is from:
http://www.netmotive.net/articles/hib/reman.html
that's the guidelines I used to wire mine in and it worked from the get-go.
I got my CS-144 at the junkyard for 22 bucks; it cost me more for the electrical adapter and the belt........it turned out to be a 140 amp unit....goofy one with a third ear; I only bought it to see if I could make it fit...and then it turns out to be in great shape...I lopped off the 3rd ear; as you can see the other 2 bolt holes are 180° apart.
You can see it bolted on - see my corvette photos here: https://www.corvetteforum.com/g/picture/6185141
AC delco part number 321-1144...
you can here to see the image, and you can search by ac delco part numbers in rockauto (if you have different part number also):
https://www.rockauto.com/en/moreinfo...sn=267&jsn=267
according to the napa website it's a 140 amp alternator.
Last edited by carriljc; Mar 19, 2022 at 01:25 AM. Reason: correct link, minor editorial changes, fixed link to article by Hib Halverson
