ONE WIRE ALTERNATOR AND JUNCTION BLOCK??

[80sHottrodder]

For my 1983 Silverado, I purchased a 140amp 1 wire alt., and the instructions say to just run a wire straight to the battery. Only thing I'm confused about is how the fuse panel will receive constant voltage. My factory wiring has a output wire from the alt running to the junction block which is fed power from the starter solenoid. Then from the junction block a wire is ran to the fuse panel. Anyone who has converted to a one wire alternator, input would be greatly appreciated!

 

[shiftpro]

Ha ha the same question has been on my mind..

 

[Blue Ox]

Isn't the wire from the starter solenoid attached to the same terminal as the battery cable? What difference will it make if you connect the alternator to the battery or the battery cable?

Or I'm not understanding what your schematic looks like.

 

[75gmck25]

It will work fine.

Stock alternator charge wire runs from the alternator BAT post to the large lug on the starter. This is the same post where you connect the starter end of the main battery cable. If you run a charge wire directly over to the battery you are just connecting to the other end of the same main battery cable. The fuse block is still connected at the starter end of the main battery cable, so it all works.

Bruce

 

[80sHottrodder]

Yall are right.Was looking at my wires wrong. Thanks.

 

[custodian]

I just ran the wire, number 10, from the alternator to the battery.

 

[Blue Ox]

140 amps through 10ga.? Seems a little light.

 

[Frankenchevy]

I like to refer to madelectrical.com for some of this stuff. I highly recommended anyone read the articles on there. There are a lot of diagrams detailing both multi and single wire alternator setups. He used to write electrical articles for the popular hot ridding magazines.

Here he compares single to multi wire alts and provides diagrams http://madelectrical.com/electricaltech/onewire-threewire.shtml

He recommends running a heavier gauge wire to a junction block.

He also says the charging wire shouldn’t be too large. It can allow too much current to the battery. charging it too quickly can reduce your battery’s life.

 

[Frankenchevy]

You must be registered for see images attach

 

[Blue Ox]

He also says the charging wire shouldn’t be too large. It can allow too much current to the battery. charging it too quickly can reduce your battery’s life.

Something is very wrong with this. Water pressure and flow is often used as an analogy for electricity, but restricting a water pipe won't start a fire. The wire needs to be large enough to carry 140 amps over the length of the circuit. Making it larger will not increase the alternator's output.

 

[gmachinz]

It one reason why imo 1-wire alts have NO place on a regularly driven vehicle. It puts out too much amperage when it isnt even needed. 3-wire setup w/remote voltage sensing is always the better route.

 

[Frankenchevy]

Something is very wrong with this. Water pressure and flow is often used as an analogy for electricity, but restricting a water pipe won't start a fire. The wire needs to be large enough to carry 140 amps over the length of the circuit. Making it larger will not increase the alternator's output.

The wires only draw what the component wants to draw, not full alternator output. Draw and potential are not one in the same. Otherwise, every wire on the battery and alternator side of the fuse block would need to be capable of carrying the full potential of the system.

Think of a home’s circuit. Although there may be 20 amp potential on a circuit, not everything on the circuit has 20 amps flowing through it. Many power supplies are 18ga for small appliances and such, while that 20amp circuit gas 12ga wiring in the walls.

The potential for fire is mitigated by a properly placed fuse or link. Think about your fuse block. All fuses, whether rated at 5 or 50 amps have the same potential on the line side, however if the load side attempts to draw more than the rated link, the fuse will fail.

 

[Matt69olds]

The wires only draw what the component wants to draw, not full alternator output. Draw and potential are not one in the same. Otherwise, every wire on the battery and alternator side of the fuse block would need to be capable of carrying the full potential of the system.

Think of a home’s circuit. Although there may be 20 amp potential on a circuit, not everything on the circuit has 20 amps flowing through it. Many power supplies are 18ga for small appliances and such, while that 20amp circuit gas 12ga wiring in the walls.

The potential for fire is mitigated by a properly placed fuse or link. Think about your fuse block. All fuses, whether rated at 5 or 50 amps have the same potential on the line side, however if the load side attempts to draw more than the rated link, the fuse will fail.

What he said. I think MAD suggests using a section of smaller wire (fusible link wire) in case the alternator internal shorts to ground, or the output wire grounds out. The thinking is the fusible link wire will melt, protecting the rest of the circuit.

 

[bucket]

It one reason why imo 1-wire alts have NO place on a regularly driven vehicle. It puts out too much amperage when it isnt even needed. 3-wire setup w/remote voltage sensing is always the better route.

Just quoting this because I think it needs more emphasis.

How the heck is a 1-wire alternator an upgrade? Far as I know, the purpose of a 1-wire alternator is just for guys building hot rods that don't feel like running the proper amount of wires.

 

[Blue Ox]

If the battery is drawn down the alternator will try to deliver 140 amps. As you said, the wiring in the house is large enough to carry 20 amps in case you plug a 20 amp load into it. If you don't want the capability of 140 amps don't install 140 amp alternator. But certainly don't try to throttle it with an undersized wire. A fuse is a different animal, but even that has to be capable of handling the alternator's output.

Frankly, as others have said, a giant single wire alternator on a street vehicle is probably a disadvantage. I usually only see them on race cars where the electrical priorities are different.