[C2] Wrong Alternator?
Thread Starter
Pro
Joined: Jul 2018
Posts: 612
Likes: 69
From: Illinois
Wrong Alternator?
I purchased an aftermarket replacement alternator for my 65. The brand new battery wasn't getting charged so I assumed the 30 year old alternator was no longer functioning. The voltage gauge was reading straight up zero. I installed the new alternator without issue, all of the connections matched correctly, then I realized it's a higher 55 AMP alternator and not the proper 37 AMP made for vehicles without A/C like mine.
Is there any concern with having a higher amperage alternator installed in the vehicle or could I damage something? Everything appears to be normal when it runs.
Is there any concern with having a higher amperage alternator installed in the vehicle or could I damage something? Everything appears to be normal when it runs.
Instructor
Joined: Apr 2007
Posts: 161
Likes: 35
From: Headed to the next race track
After verifying no loose wires, check regulator. First mine was under charging (use shop voltmeter not dash) then I cleaned regulator contacts then it was max charging .
Put a direct drop in solid state one on, best thing I ever did, wish I had done that years ago.
Put a direct drop in solid state one on, best thing I ever did, wish I had done that years ago.
Team Owner
Joined: Jul 2001
Posts: 21,398
Likes: 1,011
From: Various places in Southern California.
I don't believe a higher output alternator will cause any problems. If the regulator is functioning correctly, it won't demand any more output from the alternator than is required. So, basically, you've got some extra capacity that won't be used. No problem.
If you are concerned at all, just check the voltage across the battery terminals while the car is running. If it's 13.7-14.3, you're fine. If it's 15+, you've got a problem (which would be the regulator, not the alternator, anyway).
If you are concerned at all, just check the voltage across the battery terminals while the car is running. If it's 13.7-14.3, you're fine. If it's 15+, you've got a problem (which would be the regulator, not the alternator, anyway).
Le Mans Master
Joined: Nov 2015
Posts: 7,472
Likes: 2,647
From: Really Central IL Illinois
I Agree - The voltage regulator controls the alternator output and thus the alternator will only put out what is needed to maintain the battery charge and run accessories.
If you have not installed an electronic voltage regulator, I would do so for the intent of protecting the battery and wiring, as the original mechanical points voltage regulators sometimes stick closed and allow the alternator to induce full amperage to the battery and accessories. The electronic voltage regulator is much more sensitive to over current and will generally open if they fail.
Have a beer and enjoy your car. No worry.
If you have not installed an electronic voltage regulator, I would do so for the intent of protecting the battery and wiring, as the original mechanical points voltage regulators sometimes stick closed and allow the alternator to induce full amperage to the battery and accessories. The electronic voltage regulator is much more sensitive to over current and will generally open if they fail.
Have a beer and enjoy your car. No worry.
