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. 13.7v@ alt, 13.0-13.1v @bat
4)Car idling, fan on, AC on Max/HI, stereo on, headlights on. 13.3v@alt, 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

 

Well, the re-man operation can install whatever 'guts' they want to in the body during rebuild. I'm guessing you got a CS144 case...but not the appropriate guts on the inside. Anything to save a buck in tough times like these.... (just a thought...)

 

Yeah that thought crossed my mind also......the reason I bought a "parts store" alternator was so I could get a replacement anywhere in the country at any time...in the event I am on a road trip and it craps out....I didn't want some special order alternator that if it failed, I would be stranded without a readily available replacement.

 

Stay tuned, I'll get some volt measurements off my alternator/battery when I come back home today.

 

THAT would be awesome my friend....
Make sure to test with the AC on and blower on HI, as well as head lights and E fans on...

Thanks bro!

 

I want to know this info too...as I will be going with a single amp, A/C, stereo, E-fans in the near future as my project keeps taking more and more of my money, LOL.

thank you!

 

I purchased a used 140 amp, CS144 alternator and rebuilt it myself using a kit I purchased off of the internet with a heavy duty rectifier and regulator. I haven't had any problems running my A/C, electric fan, and stereo amp.

 

Try this test, at idle ( make it high idle not 700RPM ) in neutral turn your headlights on to highbeam, nothing else running.

Battery voltage should be 13.8 - 14.2 V and as high as 14.5V

Increase motor speed to 1500 and the voltage across the battery should be between 14.2 and 14.6 V. If it is then the alternator is fine and you are just overloading it and need a bigger one. If not one of your diodes in your bridge rectifier has failed, easy and cheap fix if you can disassemble the alternator, no soldering involved just swapping the rectifiers.

My CS144 broke a wire on the dyno at 7000RPM. Seems the armature is made of two halves and the fan belt sprocket side can move before the back half does when I punch it, just a little, and under quick acceleration it broke a wire that connects it to windings inside. So there's another downside to it.

Had to repair mine, guess I am going to have to go with some kind of racing alternator or something if I plan any trips to the track next year, or chassis dyno time when I put the new headers on

 

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.

 

Thanks a lot Hamad!

Your readings are VERY similar to mine...That makes me feel a little better......I think adding the charge wire directly to the battery from the alternator will help make up that .6v I am losing through the starter/pos cable etc.... If so, that should get me at 13.0-13.3v at the battery, that should be enough to keep it charged up. I didn't intentionally test for the hi beams but i noticed this morning my high beams were on so...maybe they were on the whole time... I will do some more testing tonight after I run the new charge wire and see what I got....... A solid 13.0v at the battery with full load should keep it charged...still a little weak in my opinion but...as long as I don't add anything other electronic draw on the system, I should be fine.....I guess I can forget about an electric fuel pump....

 

Here's what a cs144 should be putting out by alternator shaft RPM:



You probably know this, but measure the crank pulley dia and divide this by the alternator pulley dia, then multiply that result by engine rpm to get the alternator rpm's.

Even with the 108A version, you should have plenty of juice at idle (50A+).

 

How can I measure the AMPS its putting out? I know voltage but..?

I think my fan is just a freakin hog.....Its a lincoln MK8 fan so I figure it pulls 30-40amps continuous.... But even so, a CS144 that puts out 90 amps at idle should easily handle the load from a a 30amp fan, AC, headlights, stereo etc.... Its definitely no more load then a Cadillac or a cop car or something.... I figured I would have plenty of juice to spare....Looks like Hamads is close to mine, although still slightly better, particularly before he hits his AC.... I would like 13.5v at the battery at full electric load if possible...

 

You would need an ammeter of some kind. I have access to the clamp around the wire kind so you never have to break the circuit. Sears sells one for $40.

I've checked the amperage of mk8 & taurus fans before and they all draw around 25 amps once they are up to speed. My car keeps up with a 94 amp 12si alternator just fine, but my a/c isn't working right now & I use PWM controller so the fans (dual spal setup) will likely never pull full amps at an idle.

 

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 verified it had the same voltage as the alternator and it did. 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??

 

First make sure nothing is on, headlights, stereo, no fans etc. The voltage across the battery terminals should be pretty much exactly the same as the voltage right across your alternator at idle.

If it is lower then you have a drain somewhere that needs to be fixed before you do anything else.

If the voltage is the same set the idle screw up to 1500RPM and see what you get doing the same tests you did at idle.

 

Why ? You might be on to something here. This shouldn't happen.

 

I checked the voltages with the engine off.... ALT was 12.40, BAT was 12.40. Then when I started the engine with nothing on, the ALT was 14.49 and the BAT was 13.8v.

BTW, when I had the stock alternator on it, I NEVER had a charging problem, granted it was weak at idle but at 1500rpms it would be 14.0v-14.2v at the battery(although this is with no electric fan or headlights on).....but I have had the car running like that for 5 yrs and never drained a battery or had a no start episode... The only things I have changed since last month was going to the CS144 and adding the 8 ga charge wires....I don't have any electrical issues at all with this car...but I expect this CS144 alternator should be producing enough volts I could mig weld with....much less barely support electric systems in a 40 yr old car....

 

If you are checking batt voltage between the + & - at the batt you wont get the same voltage as the alt output untill the batt comes up to full charge.
Try putting the batt on charge over night and then check batt voltage not running and then running and see if that finds your .6 volt loss.
also check alt out put at the batt between the + batt lug and ground, (frame, or alt case)
If no differance then maybe the batt is week and wont take a full charge and is showing only a surface charge.

 

I've been following this from the beginning and no one has mentioned the voltage regulator. Is it an internal unit like the Delco alternator in my '72? If you have same voltage at alt. and battery with engine off and then a difference with engine running, maybe it's not the alt. but something else like the regulator? When they rebuild, they usually put in the cheapest parts. Just thinking out loud outside the box. Sometimes it helps. Good luck!

 

Voltage regulator is usually there so the alternator doesn't over charge the battery.

I would get the alternator checked, usually it takes five minutes and they shouldn't even charge you. A good alternator/starter shop should be able to tell you within a few minutes if there is something wrong with it.

Test the battery too, as stated above, batteries, no matter how good they look only last 5 years and should be replaced within that period.

Last my battery with ignition off is about 12V. When I turn my ignition on with nothing else on I read at the battery exactly what I read at across the pos. and neg. terminals of the alternator. This has to happen as all you are doing is measuring the alternator voltage at the end of long cables. You might get a slight loss ( voltage drop ) because of the cables but this is much less than 1 volt and probably in the millivolt range.

MotorHead OACETT Ceritified Graduate Electronics Engineering Technologist