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1972 Eldorado Alternator

Started by 72 Cadi-Eldo, July 09, 2021, 10:07:08 PM

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72 Cadi-Eldo

63 Amp Delco-Remy 3 wire alternator & Auxiliary wire.

Is the auxiliary wire from positive battery terminal going to the "batt" terminal on alternator supposed to be fused (have a fusible link)?
What size wire should it be?  10gauge vs 8gauge vs 6 gauge?

I have conflicting information from two trusted sources. One said yes, other not fused

Car is in shop & I need to get a correct answer to move forward:
Is the positive wire (auxiliary wire) to alternator fused from factory?

Appreciate your help.


TJ Hopland

I don't have a 72 or a 72 manual but the 73 manual says its 10 gauge and no note about fusible links there.   If I was redoing things with non repro 'correct' parts I think I would go with 8 or 6 if I had to buy something anyway. 

71 or 72 was the time frame they went from external regulator to internal.  Alternators looked pretty much the same and had the output stud then a 2 pin connector.  They bolt up fine and have the correct number of terminals but electrically are quite different and require deeper wiring changes than just the connector. 

The external regulator the connector was more square and the terminal blades would be stacked flat looking down from above as mounted in the car.    The internals the connector was rectangle and skinny side to skinny side.   

73 had an orange 18 gauge wire from terminal 2 which is further from the output stud that just went to the output stud.   Terminal 1 which was closer to the stud was a 16 gauge brown wire that eventually ends up at the GEN light on the dash.

Someone with a external regulator will have to tell you what the wire colors were and where the regulator should be.
StPaul/Mpls, MN USA

73 Eldo convert w/FiTech EFI
80 Eldo Diesel
90 CDV
And other assorted stuff I keep buying for some reason

"Cadillac Kid" Greg Surfas 15364

72 Eldo had an internally regulated alternator. The RWD cars of that year were externally regulated. I would use an 8 ga wire but I believe factory was #10.
Greg Surfas
Cadillac Kid-Greg Surfas
Director Modified Chapter CLC
CLC #15364
66 Coupe deVille (now gone to the UK)
72 Eldo Cpe  (now cruising the sands in Quatar)
73 Coupe deVille
75 Coupe deElegance
76 Coupe deVille
79 Coupe de ville with "Paris" (pick up) option and 472 motor
514 inch motor now in '73-

fishnjim

https://jascoautomotive.com/automotive-wire-amperage-capacity-chart/

Ampacity is also a factor of length and the operating conditions.  ie, shorter - more amps same size.   
The terminal lug should tell you what minimum size wire it takes, because they're also wire size rated.   If you run a smaller wire then a fusible is problem wise, but don't complain when they burn.   There should be a electrical diagram for your car online, if you search.
 

"Cadillac Kid" Greg Surfas 15364

Typically the pig tail off the positive battery cable intended to go to the charging post (BAT) of the alternator is 10Ga. on good quality cables.  FWIW I cut the pig tail off about 4 or 5 inches from the cable post end and splice in an 8Ga. Black wire, soldering the connection rather than using the crimped connection provided.  For the alternator end 8 ga. terminals for the post size are readily available. This may be overkill but in many years of doing this I have never had a problem.  This is definitely un fused and not fusible, but a direct connection between the alternator and the battery through which the battery is fed from the alternator.
Greg Surfas
Cadillac Kid-Greg Surfas
Director Modified Chapter CLC
CLC #15364
66 Coupe deVille (now gone to the UK)
72 Eldo Cpe  (now cruising the sands in Quatar)
73 Coupe deVille
75 Coupe deElegance
76 Coupe deVille
79 Coupe de ville with "Paris" (pick up) option and 472 motor
514 inch motor now in '73-

TJ Hopland

My guess is a stock 63 amp alternator would not be able to put out 63 amps for long enough to fail the 10ga wire.   They likely knew the alt would fail before the wire so no good reason to make it any bigger.  Typical use the alternator is only putting out max power for less than a minute to recover from starting.   Even with the AC and everything else on you are likely under or around 30 amps for a continuous load which is well within what we normally think of a 10ga wire good for.

If you look at more current stuff that often comes with 200 amp alternators they are not going that much bigger on the wire either,  my eyeball measuring says maybe a 6 at the largest.   
StPaul/Mpls, MN USA

73 Eldo convert w/FiTech EFI
80 Eldo Diesel
90 CDV
And other assorted stuff I keep buying for some reason

"Cadillac Kid" Greg Surfas 15364

TJ
Depending upon whose chart you read, 63 amps with a 2% voltage drop falls between 8 and 10 ga for the distance between the alternator and the battery.  Being an engineer I tend to be conservative and go bigger.
Greg Surfas
Cadillac Kid-Greg Surfas
Director Modified Chapter CLC
CLC #15364
66 Coupe deVille (now gone to the UK)
72 Eldo Cpe  (now cruising the sands in Quatar)
73 Coupe deVille
75 Coupe deElegance
76 Coupe deVille
79 Coupe de ville with "Paris" (pick up) option and 472 motor
514 inch motor now in '73-

bcroe

Same here, have a roll of 6ga welding cable for upgrading
factory alternator output to battery.  The General figured it was
pretty short, and peak current would only flow briefly (too quick
to melt insulation) right after a cranking event.  I do not see it
that way.  Bruce Roe