Charging system question
Thread Starter
Instructor
Joined: Apr 2003
Posts: 195
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From: Maple Grove MN
Charging system question
I have just put in a 90A alternator.
The '69 wiring diagram calls for 10-gauge wire leaving from the starter, then 14 gauge fusible link and then 12-gauge wire all the way to the horn relay, and again 12-gauge wire from there to alternator.
Will that support the higher amp rated alt and ensure proper charging of the battery?
Or should I:
1. Pull a thicker wire directly from alternator to the starter?
2. Pull thicker wire from alt to starter through the horn relay?
3. Pull a thicker wire from the alternator directly to the positive terminal of the battery?
Also, when I checked the current wiring, I noticed that the 14-gauge fusible link had been removed from the wire leaving from the starter,and I found a 24V!! 20A self-resetting in-line circuit breaker there. Why would anyone have done that?
Thanks in advance!
The '69 wiring diagram calls for 10-gauge wire leaving from the starter, then 14 gauge fusible link and then 12-gauge wire all the way to the horn relay, and again 12-gauge wire from there to alternator.
Will that support the higher amp rated alt and ensure proper charging of the battery?
Or should I:
1. Pull a thicker wire directly from alternator to the starter?
2. Pull thicker wire from alt to starter through the horn relay?
3. Pull a thicker wire from the alternator directly to the positive terminal of the battery?
Also, when I checked the current wiring, I noticed that the 14-gauge fusible link had been removed from the wire leaving from the starter,and I found a 24V!! 20A self-resetting in-line circuit breaker there. Why would anyone have done that?
Thanks in advance!
Instructor
Joined: Jul 2006
Posts: 208
Likes: 0
From: Hamden CT
St. Jude Donor '12
I have just put in a 90A alternator.
The '69 wiring diagram calls for 10-gauge wire leaving from the starter, then 14 gauge fusible link and then 12-gauge wire all the way to the horn relay, and again 12-gauge wire from there to alternator.
Will that support the higher amp rated alt and ensure proper charging of the battery?
Or should I:
1. Pull a thicker wire directly from alternator to the starter?
2. Pull thicker wire from alt to starter through the horn relay?
3. Pull a thicker wire from the alternator directly to the positive terminal of the battery?
Also, when I checked the current wiring, I noticed that the 14-gauge fusible link had been removed from the wire leaving from the starter,and I found a 24V!! 20A self-resetting in-line circuit breaker there. Why would anyone have done that?
Thanks in advance!
The '69 wiring diagram calls for 10-gauge wire leaving from the starter, then 14 gauge fusible link and then 12-gauge wire all the way to the horn relay, and again 12-gauge wire from there to alternator.
Will that support the higher amp rated alt and ensure proper charging of the battery?
Or should I:
1. Pull a thicker wire directly from alternator to the starter?
2. Pull thicker wire from alt to starter through the horn relay?
3. Pull a thicker wire from the alternator directly to the positive terminal of the battery?
Also, when I checked the current wiring, I noticed that the 14-gauge fusible link had been removed from the wire leaving from the starter,and I found a 24V!! 20A self-resetting in-line circuit breaker there. Why would anyone have done that?
Thanks in advance!
Not sure on the 24V 20A circuit breaker but it doesn't sound right to me. I would think a 12V 15A circuit breaker would be more appropriate as 14 gauge wire typically handles about 15A of current.
Le Mans Master
Joined: Oct 2006
Posts: 7,123
Likes: 433
From: Gladstone MO
C3 of Year Finalist (appearance mods) 2019
The circuit breaker, especially a self resetting breaker, in the main power feed seems a bit like a place for a failure (fire). The fusible link has way more protection built in. Although it does have the ability to drop you where it is, I'd much prefer that than trying to figure out where all the smoke is coming from.
And I agree that the stock wiring is fine. Any alternator is going to have only the output needed to run whatever accessories and keep the battery charge at the desired level. A 45 amp alternator would be fine if you don't run anyhing but lights at night. A 125 amp will power the lights, a/c, windows. door locks, and that killer stereo amp all at the same time.
And I agree that the stock wiring is fine. Any alternator is going to have only the output needed to run whatever accessories and keep the battery charge at the desired level. A 45 amp alternator would be fine if you don't run anyhing but lights at night. A 125 amp will power the lights, a/c, windows. door locks, and that killer stereo amp all at the same time.
Team Owner
Joined: Jan 2006
Posts: 37,637
Likes: 3,118
From: Crossville TN
Someone put a circuit breaker in there because the installed a high-powered audio system or electric radiator fans [or both] on the car and kept blowing fusible links (ya' think???).
If you have need of a high output alternator, the wiring from it and to the battery should be upgraded for that current level. Since the stock wiring is 10 ga. with a 14 ga. fuse-link, I would think that an 8 ga. main wire with a 12 ga. fusible link would suffice for 90 amp service. If you have a big woofer in the car and turn it way up, you can probably get higher peak current loads than what the alternator can provide {the battery supplying the overage}, so you could still have some over-current problems with fusible links. If that is your situation, you could always wire it with the fusible link in place but also install a fast-action circuit breaker in the audio system circuit to handle an excessive current spikes.
If you have need of a high output alternator, the wiring from it and to the battery should be upgraded for that current level. Since the stock wiring is 10 ga. with a 14 ga. fuse-link, I would think that an 8 ga. main wire with a 12 ga. fusible link would suffice for 90 amp service. If you have a big woofer in the car and turn it way up, you can probably get higher peak current loads than what the alternator can provide {the battery supplying the overage}, so you could still have some over-current problems with fusible links. If that is your situation, you could always wire it with the fusible link in place but also install a fast-action circuit breaker in the audio system circuit to handle an excessive current spikes.
Le Mans Master
Joined: Oct 2006
Posts: 7,123
Likes: 433
From: Gladstone MO
C3 of Year Finalist (appearance mods) 2019
Power for the electric fan should come directly from the battery- like from the starter lug and thru a relay to control it. Low voltage to an electric motor is asking it to run with high amperage. Most electric fuel pumps like full voltage too.
