Alt wiring

[cpisani70@aol.com]

trying to convert to a 1 wire Alt in my 68 does it matter where i tie into the circut with the red wire? What becomes of the brown wire? Any help would be great i want to start pulling some new wires.

[dmwphoto]

I just folded up the original alt harness and taped it up near the drivers headlight. Ran a 10 gauge wire from new alt to battery voltage terminal on the right fender
Posted via Mobile Device

[dznucks]

There are some good threads on the site about how to wire the 1 wire alt.
It is best to go with the 3-wire setup, but thats your call.

[haysonj]

Originally Posted by dznucks

There are some good threads on the site about how to wire the 1 wire alt.
It is best to go with the 3-wire setup, but thats your call.

I am being told this on the Edelbrock site also but no one will tell me why My computer for the fuel injection reads 13.1 volts with the one wire but only reads 12.4 with the three wire and I get a low voltage alarm. Why is the one wire bad.

[cpisani70@aol.com]

When you taped up the old wires and ran the new wire did the factory gauge still work???

[dmwphoto]

Yes. It just reads voltage. If you had a light instead of a gauge it may be mor complicated.
Posted via Mobile Device

[ERASER5]

A volt meter will work. The factory ampmeter will not.

[ERASER5]

Originally Posted by haysonj

I am being told this on the Edelbrock site also but no one will tell me why My computer for the fuel injection reads 13.1 volts with the one wire but only reads 12.4 with the three wire and I get a low voltage alarm. Why is the one wire bad.

How did you wire your 3 wire alt? Did you do just jumper a wire from the output terminal to the votlage sence input? Or did you keep the factory wiring intact?

If you did the short jumper, you will get low voltage elsewhere in the system. The voltage sence reads the voltage AT the alt and reducese the output to maintain 13 ~14vdc right there. No voltage drop is accounted for. Several feet of wire later, the wire resistance has dropped the voltage too low for your system.

The factory wiring had a "remote" votage sencing wire tied into the system several feet and some load away from the alt. Now the alt pumps up the voltage to account for voltage drop and you can read proper voltage all the way to your computer.

A 1 wire alt just blasts high voltage regaurdless of the load. It looks good at first, but it can do bad things like cooking the battery, and not charging at all at idle.

Fixitp has a nice write up some where around here.

[haysonj]

Originally Posted by ERASER5

How did you wire your 3 wire alt? Did you do just jumper a wire from the output terminal to the votlage sence input? Or did you keep the factory wiring intact?

If you did the short jumper, you will get low voltage elsewhere in the system. The voltage sence reads the voltage AT the alt and reducese the output to maintain 13 ~14vdc right there. No voltage drop is accounted for. Several feet of wire later, the wire resistance has dropped the voltage too low for your system.

The factory wiring had a "remote" votage sencing wire tied into the system several feet and some load away from the alt. Now the alt pumps up the voltage to account for voltage drop and you can read proper voltage all the way to your computer.

A 1 wire alt just blasts high voltage regaurdless of the load. It looks good at first, but it can do bad things like cooking the battery, and not charging at all at idle.

Fixitp has a nice write up some where around here.

I have a complete rewire with a Painless wiring harness and is wired per their instructions. I also have the charge wire going to a very expensive battery isolator that is suppose to protect the batteries. It works fine with the one wire but does not work with the 3 wire wired the way painless says to do it.

[cpisani70@aol.com]

So the factory gauge says battery does that guage read volts bercause it would be nice if having it work was that simple.

[haysonj]

Originally Posted by cpisani70@aol.com

So the factory gauge says battery does that guage read volts bercause it would be nice if having it work was that simple.

The factory gauge on my 69 is a amp gauge it shows charge or discharge A Volt gauge will show volts like 11,12,13,14. They had a special resistance wire to go through the factory amp gauge. I've been told you can't make it work with the three wire but I really don't know.

[ERASER5]

Originally Posted by haysonj

I have a complete rewire with a Painless wiring harness and is wired per their instructions. I also have the charge wire going to a very expensive battery isolator that is suppose to protect the batteries. It works fine with the one wire but does not work with the 3 wire wired the way painless says to do it.

Hmm. Obviously something is wrong. Could the plug be wired backwards? I know it will not charge that way. When I converted to internal reg, I just pushed the original terminals into a new plastic holder. No charge, swapped wire positions, good to go.