NOT CHARGING - 1970 CADILLAC

[trini 140]

Do a battery load test.

[The 55er 313]

1966 Pontiacs have an ammeter in the dash, there is no idiot light, just sayin'. 

[padgett 1,228]

That was about the time some car lines got a 10SI (internal regulator) and think it was about '72 before all of the 10DNs (external regulator) were replaced. If you can be specific about the year, engine,  make, and model I can tell you which alternator was supplied. Near 50 years on 10DNs were often replaced by 10SIs but normal car lines still had less than 100A, base models often had a 37A.

 

Delco alternators usually had a contact on the back near the bottom where you could stick a screwdriver while running and it would go to max output.

 

Upgrades are popular and common, think the max is about 140A

 

Back in the day I used to reverse the diodes in a 10DN & use in Jags with lotsa halogen lights (had to be imported then).

 

BTW you realize this thread is from 2015 ?

[66-pontiac 2]

K... turned everything on; lights, heater/fan, radio.... put the meter on it read back forth between 12.7 to 12.9.... talk of the alternator its a 60 amp unit from rockauto, has a needle guage in dash no light.

 

volt regulator is like the alternator 3 wires- I’m in Alaska its 15 snowing (that will be the extent of my whine lol) 

 

started right up no jump but I brought the battery in charged it up cleaned the heck out of the terminally and connectors- 

 

wonder if a guy can run a 10 gauge from that alternator to the positive terminal? 
 

an old guy said if the battery is good the alternator won’t come up? I dunno thought it was always 13 or + so running... 

 

 

 

 

[66-pontiac 2]

1966 389 Catalina BOAT lol my baby lol

 

K... turned everything on; lights, heater/fan, radio.... put the meter on it read back forth between 12.7 to 12.9.... talk of the alternator its a 60 amp unit from rockauto, has a needle guage in dash no light.

 

volt regulator is like the alternator 3 wires- I’m in Alaska its 15 snowing (that will be the extent of my whine lol) 

 

started right up no jump but I brought the battery in charged it up cleaned the heck out of the terminally and connectors- 

 

wonder if a guy can run a 10 gauge from that alternator to the positive terminal? 
 

an old guy said if the battery is good the alternator won’t come up? I dunno thought it was always 13 or + so running... 

 

 

 

 

[padgett 1,228]

10ga can carry about 30A, need 0 or 00.

 

Alternators typically put out 1-2V more than the battery voltage.

[Bloo 1,337]

Have you checked the voltage at the alternator AND the battery? Are they close to the same? Try it with the engine not running, or running. Either way, the results ought to tell us something.

 

Figure out whether that circuit is broken before you go about replacing it. As referenced by the earlier Cadillac posts, there is probably a fuse or fuselink, and it's probably bad. I'm betting on a fuselink.

 

If that circuit proves to be good (I doubt it), the next step would be to "full field" the alternator to see if THAT makes it charge.

 

Yes 12.7-12.9 means it isn't charging. It probably charged at about 14.2V when new, however GM (apparently) jacked up the charging rate around 1976(?) to better match the chemistry of their newly introduced "Freedom Battery". 14.7 or so became the norm for GM, and the aftermarket quickly followed suit with their voltage regulators. Today GM cars in the wild (with alternators) are usually found to be charging at the higher rate, even when they are much older than 1976, all the way back to the first Delcotron alternators.

 

These numbers are not absolute, although they are pretty close at room temperature. Regulators are usually temperature compensated, and may jack the voltage up a tenth of a volt or two in the cold.

[trini 140]

Fuse in the harness  usually  affect the ignition. The engine will crank but there will be no ignition.  fuse in the  the harness?  Look for an unusually "fat"  lumpy wire about 2 inches long compared to the rest of the wire in the harness. To repair open the fat part and replace with an inline fuse.

Newer alternators has built in regulators. There are new versions with only one wire.. A short check is hook a jumper from the battery direct to the B terminal and use a jumper directly from the F terminal to the battery and run the engine at about 1000 rpm. with engine running turn on all bells and whistle and the engine will slow down.. GOOD GROUND IS A MAJOR PROBLEM. ENGINE TO FRAMEAND FRAME TO BATTERY.  Infrequent driving or  not driving enough to allow the battery to charge is a major problem especially with generators.   A WARM GROUND WIRE IS AN INDICATION OF POOR GROUND.

[trini 140]

You may put 4zero wire to the "BAT" terminal. It will make no difference. Just use a 12 gauge directly from the battery to the "BAT " terminal" Use a short jumper and attach one end to the battery and chuck the other end in the "F" terminal. That is to excite the field. (bypassing the key) That's all. Done. With engine running the charge should be 14.5 more or less. If the charge is above that , higher than 15 the battery is dead   If no charge look for poor ground . Leaving the jumper perminantly   from battery to "b" terminal will not cause any harm  There is a diode behind the "BAT" terminal that prevents the flow back . Look at the back of the alternator, just below the bearing, there is an elongated slot. Push a cotter pin in hard, that will ground the field brush. The voltage will go up to 18 volts. DO NOT HOLD FOR LONG. That is how to test internal problems in alternators with built in regulators.   Do the test with engine running of course.

[Marty Roth 1,848]

Just a gentle reminder in addition to all the excellent notes already posted-

 

When cleaning the ground connection, be sure to not only clean both ends of the wire, but also the surface to which they ground,

remembering to remove painted surfaces from the restoration.

 

You likely know this already, but sometimes a reminder triggers the "Oh-wow - That's what I did" moment-

ask me how I know...

[66-pontiac 2]

Ok... thanks to everyone tomorrow I will be a continuity checking guy- I want to check fuse-able links are shot. I would like everything to be square anyhow.  

reading all the importance of steps and ground etc... heres a btw: 

 

the ground for the voltage regulator (I assume) would be where its attached to the firewall, the other day when I put the new unit on; in the cold I lost 3 of the screws.... I figured one would be enough(?) but if that is indeed how its grounded maybe I should quit halfa*** things lol...  Or maybe that’s not how it’s grounded I gotta do it right though. 

 

ALL OF EVERYONE’s responses are much appreciated- This car being older than me by 11 years- my hat is off to this forum and all the members. I will be letting everyone know-

 

I start the car once a week let it run half hour. 

[Frank DuVal 722]

13 hours ago, trini said:

As far as I can tell with certainty G M vehicles of that era does not use external regulator.

 

I've never seen a stock 66 GM product that DID NOT have an external regulator! 😲

 

Those internal regulator Delcotrons were a 70's design. 😉

[Bloo 1,337]

These are externally regulated.

 

[trini 140]

Bloo, You are right, but the car in question is a 1970 Cadillac.  If it is a  change over period then it might still have the outside regulator.

The easiest thing to do is to install one with internal regulator and leave the old regulator in place just for show. The "BAT" wire on the regulator could connect on the "BAT" terminal on the alternator and the field  wire could be attached to the "F" terminal on the alternator. Save yourself a lot of headache today and for the future. The "I" terminal is probably connected to the "BAT" terminal somewhere and is controlled by the ignition key. When the key is turned "ON" the dash gauge shows battery voltage.  THIS IS JUST MY THOUGHT. Old style housing is smooth outside and the new style has lots of ridges on the outside. I donot have my camera to show a picture of the difference. By the way I would just like to mention to check  if the new style alternator is charging touch a screwdriver blade on the bearing button with the engine running . There will bea strong magnetic pull.

CHEERS.    

[Bloo 1,337]

Actually, it's a 1966 Pontiac Catalina.

[66-pontiac 2]

Alright.... broken brown wire. Replaced, sitting idle now 13.01. Everything on 13.9 to 14.21 good for now- thanks everyone! 
 

This summer I am going to go over all these old dry cracked wires- 

Went to gas station 3 times, 5 gallon at a time, its got a full tank- 

 

Checked all fluids, heats on thawing out. Let it run for 40 minutes. One day I will have a garage lol. 
 

thanks again everyone- 

 

 

[trini 140]

I do not know what kind of charging system there in in the 1966 Pontiac but the one thing I detest most is a flat battery and no start. With a flat battery charged by generator , push the car and let the clutch out. With an alternator, no dice. It needs a little bit of juice to excite the field.