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Old 01-24-2018, 07:31 PM   #1
chip46wis
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One wire alt. and fan relay on POS side battery?

Ok---getting to final wiring on my 56 Question---I already have my one wire alternator 105 amp running to the pos side of the battery 8 gauge wire---------Can I also run the 10 gauge wire from the pos terminal ---fused to the relay for the 1 1600 cfm fan without overloading the fan wire? just seems all the alt juice is going to overload the fan wire? same terminal.
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Old 01-25-2018, 02:15 AM   #2
VetteVet
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Re: One wire alt. and fan relay on POS side battery?

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Originally Posted by chip46wis View Post
Ok---getting to final wiring on my 56 Question---I already have my one wire alternator 105 amp running to the pos side of the battery 8 gauge wire---------Can I also run the 10 gauge wire from the pos terminal ---fused to the relay for the 1 1600 cfm fan without overloading the fan wire? just seems all the alt juice is going to overload the fan wire? same terminal.
This is a common misconception among people who don't understand how the alternator works. Even though the alternator is capable of putting out 105 amps, it will only generate enough to maintain the circuit voltage that the system is designed for, and to keep the battery charged. Everything in the truck is an amperage draw including the battery. The alternator will only put out enough to satisfy that draw and keep the battery charged.

Think of it this way. If you have a 1000 GPH water pump in your house and you change it for a pump that is capable of 3000 GPH, is that going to burst water pipes. The alternator is just an amperage pump that will output up to it's capacity. Now if the wire was too small to carry the load of the fan, then it would burn up due to it's resistance, but the alternator would not be at fault.

Here is a nice diagram of how to wire a single fan, and it even shows how to wire in a bypass switch to turn on the fan, and a light to show that the fan is running.


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Old 01-25-2018, 03:11 AM   #3
chip46wis
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Re: One wire alt. and fan relay on POS side battery?

Vettevet you have helped myself and MANY others again and again----THANK YOU!!!!!
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Old 01-25-2018, 10:43 AM   #4
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Re: One wire alt. and fan relay on POS side battery?

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Vettevet you have helped myself and MANY others again and again----THANK YOU!!!!!
Your very welcome.
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