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Discussion Starter #1
I got my car running finally after a bunch of mods, one of which is an electric fan/cs144 conversion. Everything is working fine, even the factory ammeter but I question the voltage output on the Cs144. I thought for sure it would be complete overkill for my car which I liked but...now I'm wondering if it will keep up. Here is what I've got:

Re-man CS144 from Oreily- Ultima life time warranty. 8ga charge wire to the starter lug, 8ga charge wire to the horn relay.

Voltages:
1)Car idling, nothing on. 14.49v @ alt.
2)Car idling, electric fan on. 13.90v @ alt, 13.30v at battery terminals.
3)Car idling, fan on, AC on Max/HI, stereo (single amp) on. [email protected] alt, 13.0-13.1v @bat
4)Car idling, fan on, AC on Max/HI, stereo on, headlights on. [email protected], 12.6-12.7v @bat.

Revving the engine to around 2000rpms only raises the voltage up about .1v on any of these tests...to me, it seems that this cs144 is not ramping up enough voltage under full load. I thought considering this alternator is for a Caddy Deville, I would have way more power then I would ever need but not the case.

I will be running another 8ga charge wire directly to the battery to help make up the .6v I am losing apparently by going to the starter lug/pos cable. Maybe the extra charge wire direct to the battery will help but, it still seems like 13.2v @ the alt at full load seems low to me....


Any of you guys ever taken any voltage vs. Load readings with a Cs144 ??

Thanks
 

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Discussion Starter #3
I'll check mine today and post the results. I don't have a/c, but that shouldn't change the readings much. Sounds like you have a bum alternator.


Hamad just tested his for me:



Originally Posted by HamadUP
"I just made some measurements for you, here are the results :


1- Engine idle @ 800 rpm, nothing on : Alt. = 14.4 - Batt. = 13.9
2- Engine idle @ 800 rpm, lights on (including bright) : Alt. = 14.3 - Batt. = 13.9
3- Engine idle @ 800 rpm, adding dual spal fans : Alt. = 14.3 - Batt. = 13.6
4- Engine idle @ 700 rpm, adding A/C : Alt. = 13.7 - Batt. = 13.0

You'll notice that when rpm dropped, the voltage also dropped a little, so thats not related to the performance of the alternator, I tried to bring up the rpm to 800 rpm while taking the readings, but I was alone and it was dark outside and the wife was calling for dinner
.


My alternator is the CS-144 but its the 1st generation (came off '87 or '88 cadillac, not sure) that has a little different housing, and I heard that the later ones (the one that you have) are better, so your readings should be better than mine. I have this setup for two years now and my '71 is a daily used car with no problems what so ever, always starts as it should, and even when I went for a two weeks trip it still started fine when I came back.

The wiring is pretty much stock, except one additional 10 ga wire (with a fusible link) from the starter's lug to the (+) terminal in the alternator.

I don't have a stereo system, but I thought the second fan may compensate that."




So his is a little better then mine but not much....he pretty much has the same stuff except his has dual spals and mine is the lincoln mk8. I am going to run a seperate charge wire directly to the battery to make up the .6v I am losing through the starter/pos cable....Hopefully that helps some but I definitely thought this CS144 should have had way more juice under load...:rolleyes:

Any test info you can get would be greatly appreciated... I will do the charge wire tonight, perform the tests again after its good and hot and see what I have...
 

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Question, when you wired your alternator, did you include resistance to the brown wire? Cars that have a GEN light don't need any extra resistance but yours would.

Explain the procedure you used to wire your alternator to the stock harness.
 

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Discussion Starter #5
Question, when you wired your alternator, did you include resistance to the brown wire? Cars that have a GEN light don't need any extra resistance but yours would.

Explain the procedure you used to wire your alternator to the stock harness.
Yes I bought the AC Delco si to cs adapter with the resistor built in. Mine charges as soon as I start it and no revving needed to initiate the charge...it just doesn't seem to produce enough juice once all of the load is applied in the car.
 

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Voltage is not what charges your battery, its the current output. A 12v battery only has to stay above about 12.5 volts to charge. any thing over that with all your acceories on will be charging the battery.

But it does sound like you have a battery terminal or ground problem with that much drop to the battery.
 

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Discussion Starter #7
Voltage is not what charges your battery, its the current output. A 12v battery only has to stay above about 15.5 volts to charge. any thing over that with all your acceories on will be charging the battery.

But it does sound like you have a battery terminal or ground problem with that much drop to the battery.

15.5v? Or 13.5v
 

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Re-man CS144 from Oreily-
I'm guessing that might be the cause of your lower readings than Hamad. What is the amperage rating of the CS144?
 

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Discussion Starter #10
Well a whole night of testing/playing and no progress. I added an 8ga charge wire from the alt to the battery, before I hooked it up, I verifiedit had the same voltage as the alternator and it. I hooked it to the battery and the battery voltage came up .1v. Thats it....
At that time, I had just started the car and everything was cold so voltage was high, 14.49v at the alt, 13.86 at the battery and with the additional charge wire hooked up, 13.95v. So not much of anything. So I continued on with my tests....Here is the data after 30 mins of run time...

Idling, headlights on:
Alt 14.00v, Bat 13.39v

Headlights, fan on
Alt 14.00v, Bat 13.31v

Headlights, fan, AC(Max/HI)
Alt 13.83v, Bat 13.00 but will eventually drop to 12.70-12.75

Headlights, Hi Beams, fan, AC(Max/HI)
Alt 13.5-13.6, Bat 12.65 and eventually down to 12.5v

So basically, after its hot and at full load, I lose 1v between the alternator and the battery. Running the charge wire directly to the battery didn't really help. Then I thought maybe its a ground issue so I ran a 10ga ground wire from the alternator ground lug directly to the neg terminal on the battery..... THEN I was only getting 12.8v at the alternator and 12.6v at the battery....Immediately after that I disconnected the added ground wire and shut the car off, restarted it and brought all the load back on and the alternator was back at 13.5....No load it was back at 14.00v....

It seems the alternator is making the juice, I am just losing it at the battery somehow...
Any ideas??:thud:
 

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How clean are all of your frame connections? You want to remove paint at all of the heavy connections so they make solid contact. Something to check out anyway.
 

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Discussion Starter #12
How clean are all of your frame connections? You want to remove paint at all of the heavy connections so they make solid contact. Something to check out anyway.
The ground connections at the frame were recently wire wheeled down to the bare frame and and new THICK gauge cables were installed. Braided ground strap from frame to the starter is in place. New ground cable from the frame to the motor mount also....
 

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out of curiosity, what's the condition of the battery? New, old, gel cell?
 

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Discussion Starter #14
out of curiosity, what's the condition of the battery? New, old, gel cell?

Battery is about 1yr old, Duralast Gold 850 CC....The car has been sitting for 5 wks, I never put the charger on the battery and it still fired right up last sunday.....Battery voltage is 12.4 engine off. Even when this battery was brand new it only had a 12.45v steady charge.

As mentioned, I never had any charging issues with this car with the stock alternator and non electric fan. I have owned it 5 yrs and never a no start episode....the only thing I changed was while the rear end was out, I went to the CS144 and lincoln MK8 fan. Now with the lights, AC, fan on, the voltage will barely maintain 12.6v at the battery, yet its 13.6 at the alternator...:crazy:
 

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I'm not sure it's worth it to get to hung up on the voltage at the battery. It looks like Hamad was loosing about 0.7 V between his alternator and battery. You're right in that same ballpark. As Ivan mentioned, the amperage is what's really critical.

Something to consider... As you turn on more accessories and the current draw on the electrical system increases, the voltage drop across any given resistor will be greater. According to Ohm's Law:

voltage = current*resistance (or V=iR)

So as current goes up, so does voltage. Your battery cables have some inherent (and constant) resistance, so you should see more a voltage difference between alternator and battery when you have a high current draw than when you have very little. Just something to consider.
 

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What is it you are trying to achieve??? Over charging your battery will burn it up in a short period of time. Your regulator will turn off your alternator as the battery reaches full charge. After starting you car you will have discharged the battery a bit and the alternator out put will be higher, it will drop as the battery regains full charge.

A 12v Battery is fully charged at 12.7 volts.
 

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Sealed Lead Acid batteries prefer a fast charge regime That is a 14.7V fast charge voltage and then taper off to a 13.8V end of charge trickle. The newer GM vehicle have adopted this scheme as well with the PCM controlling the alternator voltage to a higher level right after you start the car and taper it back off to the lower level.

This scheme has been used by the battery charging industry for decades.

Your CS144 should be outputting closer to 14.1 - 14.2 V at the alternator, regardless of the load. The voltage drop occurs in the cabling and connections, not at the source. There is little to no resistance at the BAT+ terminal of the alternator from the diodes-regulator location. The CS144 uses a parallel diode architecture to minimize drop and maximize heat dissipation. It shouldn't be dropping out.

What is the resistance value in your SI to CS pigtail. I have seen 80 to 300 ohms in schematics and words of advice, but it is supposed to mimick the DC resistance of you dash generator indicator light bulb.
 

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Discussion Starter #18
I just read all of this:
http://www.madelectrical.com/electricaltech/chevymain1.shtml

Good info there. They state that .4-.5v drop from alternator voltage to battery voltage is normal and actually anticipated by the original Delco Remy engineers who designed the wiring. Also something about where the sensing wire for the voltage regulator gets signal from a wire splice/junction in the harness. Not from the horn relay or battery voltage...

Ofcourse none of this helps me much as I am still only getting 12.6-12.7v at the battery when hot and under full load...that will probably not keep it charged. So I need to either minimize the voltage drop from the alternator to the battery or get more juice from the alternator at full load.
 

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Discussion Starter #19
I'm not sure it's worth it to get to hung up on the voltage at the battery. It looks like Hamad was loosing about 0.7 V between his alternator and battery. You're right in that same ballpark. As Ivan mentioned, the amperage is what's really critical.

Something to consider... As you turn on more accessories and the current draw on the electrical system increases, the voltage drop across any given resistor will be greater. According to Ohm's Law:

voltage = current*resistance (or V=iR)

So as current goes up, so does voltage. Your battery cables have some inherent (and constant) resistance, so you should see more a voltage difference between alternator and battery when you have a high current draw than when you have very little. Just something to consider.

I just re-read your post....that completely jives with what I saw on my tests last night.....the more load I put on the system, the more voltage drop between alt voltage and bat voltage....interesting.


I'm tempted to just let it ride and see what happens....I guess if the battery never drains, I "really" don't have a problem. Most of the time I won't have the hi beams on either....but I always drive at nigh and have the ac on(now now the e fan) so this large load on the system will be a common occurrence. I will keep researching this though...

I'm almost wondering if I should swap out this alternator for another? Maybe I tweaked something in it when I reclocked it?(I only pulled the front case off, not the armature etc)
 

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OK I installed my little digital voltmeter directly to the pos/neg terminals at the battery and went for a drive. Although the voltage is lower then what I would like and expect, I think it may be sufficient. I drove around about 30-40 mins in various traffic/cruise conditions, AC on (Max/HI), Fan on, headlights on, stereo on and even the high beams on....After everything was up to temp, I was averaging anywhere from 13.3-13.6v going down the road at 2000rpms, idling at stop lights with everything on and idling at around 750-800rpms it would sit at 12.9-13.0v most of the time, with the headlights on but no hi beams......With hi beams on and brake lights, pretty much everything I can turn on in the car, I saw 12.5v once but it was mostly 12.6-12.9v, depending on the cycle of the compressor/fan...Ofcourse if I was in a bad traffic jam in the middle of summer and I had everything turned on for an extended period, I might be in trouble, but I would imagine it would take a while to drain the battery from extended idling with everything on, hopefully once moving again and the fan goes off, the system will recover....
I guess I will let it ride and see what it does. I don't want to be chasing a ghost in my car that may not be there but I am definetly not overly excited about the lack of charging performance from the CS144....i would expect this kind of performance out of the original 63 amp alternator and maybe even a 100amp but a 140? I should be able to weld with this thing...


Thoughts?
 
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