140 amp alternator
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Intermediate
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140 amp alternator
I am putting a Spal fan on my 73 454 (runs too hot), so I bumped the alternator to 140 amps. There is a 9 guage wire with a fusable link from the alternator post to the starter motor (via the horn relay). The guy that rebuilt the alternator suggested I run another 9 guage wire from the alternator to the starter moter (to provide more amps to charging the battery) Has anyone done this?? If so what size fuse did you put in-line or did you use fusable link wire (I can't find anyone that sells it) Thanks
Race Director
Joined: Mar 2006
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From: Florida
9 gauge isn't very common, so an 8 gauge wire with a run of less than 10 foot will need a circuit breaker of 40 amp capacity. The breakers are available at any parts store and like the fuseable links, they don't blow as fast as a fuse. The breaker is available as a self resetting too.
Team Owner
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From: Columbia Missouri
The extra wire is a good idea, but you don't have to find a fusable link...you can run the wire through a breaker. That'll provide the same safety but in the event of a blown wire the wire won't be junk, and you can just reset the breaker.
Le Mans Master
Joined: Jan 2006
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From: Boca Raton Florida
Why do you need to provide more charging current to the Battery? You are doing NOTHING that affects the battery.
All you need to do is put #8 wire from the alternator to a term post and a set of relays for the fans. Put this on the fender well next to the alternator. The fans will be running only when the engine is running and there is no reason to ship the current for the fans from the alternator, down past the starter to the battery and back.
Use something like this. This was done by BeeJay and its a good setup
All you need to do is put #8 wire from the alternator to a term post and a set of relays for the fans. Put this on the fender well next to the alternator. The fans will be running only when the engine is running and there is no reason to ship the current for the fans from the alternator, down past the starter to the battery and back.
Use something like this. This was done by BeeJay and its a good setup
Team Owner
Joined: Aug 2006
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From: Columbia Missouri
Originally Posted by SIXFOOTER
Use something like this. This was done by BeeJay and its a good setup
I'd love to see that setup with a cool clean compartment to keep everything safe and shielded. Maybe a custom relay box.
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Joined: Jan 2003
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From: Austin TX
I have a 140 amp alternator. I looked at the Powermaster web site to find the wire size. See:
http://www.powermastermotorsports.com/charge_wires.html
It does not say anything about a breaker or fusible link. Consequently I do not have a breaker, etc. in the line. Am I taking a risk I don't know about?
By the way I ran a 4 gauge wire from the alternator to the battery. It is very thick, but seems to work fine.
http://www.powermastermotorsports.com/charge_wires.html
It does not say anything about a breaker or fusible link. Consequently I do not have a breaker, etc. in the line. Am I taking a risk I don't know about?
By the way I ran a 4 gauge wire from the alternator to the battery. It is very thick, but seems to work fine.
Team Owner
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From: Springfield MO
St. Jude Donor '07
Originally Posted by Durango_boy
I'd love to see that setup with a cool clean compartment to keep everything safe and shielded. Maybe a custom relay box.
Team Owner
Joined: Aug 2006
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From: Columbia Missouri
Originally Posted by I'm Batman
The Lincoln Mark VIIIs have an awesome underhood fuse/relay box. I need to grab another one for the '54 GMC. Just gotta sand the "Ford" logo off of the top and find a nice bowtie sticker.
We should add a couple of those to our pick'n pull shopping list.
Melting Slicks
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As mentioned above you don't need a larger wire to charge the battery, you just need a larger wire to the horn relay junction lug to power the accessories. This lug is the central distribution point to all electrical loads in the car, and when you install your electric fan connect it to this same lug.
Team Owner
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From: Columbia Missouri
Originally Posted by shafrs3
As mentioned above you don't need a larger wire to charge the battery, you just need a larger wire to the horn relay junction lug to power the accessories. This lug is the central distribution point to all electrical loads in the car, and when you install your electric fan connect it to this same lug.
Does that junction have an amperage limit to watch for?
Melting Slicks
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No not really. The important thing is to upgrade the wire from the alternator to that lug. The only thing to watch for is getting to many connections on that lug, not because of electrical loading but physically, you can only stack so many terminals on it. Jegs has a junction that has two lugs that I'll be using when I get around to it.
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I am not an EE, but I have been schooled over the years by some pretty knowledgeable folks. It has always been my understanding that all electrical equipment is run by the battery and the only function of the alternator is to keep the battery charged. Therefore I will get the second wire from the alternator as close to the battery as possible (for me that will be the starter solenoid) I do plan on hooking the fan terminal to that same location, not so it is close to the alternator but because it is a handy place to connect to the battery. It seems to me that if you connect the second alternator to the horn relay post and then hook the fan to that same post that you accomplish very little except put a lot more amp load on the wire running from the starter solenoid to the horn relay and risk burning up that fusible link wire.
Melting Slicks
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Nope, it's the other way around. If all electrical loads were supplied by the battery then if you disconnected it while the car was running the car would die. The battery is only for starting the car.
Last edited by shafrs3; Oct 4, 2006 at 04:32 PM.
Team Owner
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From: Columbia Missouri
Originally Posted by shafrs3
Nope, it's the other way around. If all electrical loads were supplied by the battery then if you disconnected it while the car was running the car would die. The battery only is for starting the car.
That's what I've heard as well.
Le Mans Master
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From: Boca Raton Florida
Originally Posted by shafrs3
Nope, it's the other way around. If all electrical loads were supplied by the battery then if you disconnected it while the car was running the car would die. The battery is only for starting the car.
Team Owner
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From: Springfield MO
St. Jude Donor '07
Originally Posted by SIXFOOTER
Thats exactly correct. There is no need for a big new wire back to the battery for your fans and nice big new alternator. The charging current needed to recharge the battery after a start is all that is going back there and the existing harness is more than capable of suppying that. Moreover, putting a large conductor essentially from the alt to the battery will run the risk of overcharging the battery, The charging system is calibrated to use the inherant voltage drop in the stock harness to keep the charge voltage at the battery within limits.