1-wire alternator question

[68bowtie]

Am I crazy or is wire #915 not necessary?

[siggyfreud]

I'm not sure why it's there since it should get power from #916 anyways.

[tdangle]

Could it be so the battery meter (pseudo amp meter) works correctly. It shows the difference in the current at the battery and output of the alternator.

[HO455]

I believe Tdangle is correct. The drawing is incomplete and only shows the main power circuit.

[68bowtie]

Thanks. Glad I asked, apparently I need to do a bit more research.

[68Gold/white]

One thing, I've read, here, and other places. With a one wire alternator, it is a good idea to ground the alternator case directly to the battery. I don't have the knowledge to tell you why, BUT it couldn't hurt!!! The electron flow to and from the battery will not be interrupted. A ground wire directly to the distributor is a good thing, also...

[firedemon]

possibly to help with voltage drop in a long distance wire

[weq92f]

Originally Posted by firedemon

possibly to help with voltage drop in a long distance wire

This is why I ended up running big ground directly from case to battery...was chasing voltage drop.

-klb

[firedemon]

the 3 wire type are better with a ground too

[MARKDTN]

Why do you want a 1-wire? They work great in equipment that cranks and runs all day with minimal accessories but not as nice in a vehicle with variable amp draw. I would wire it as a 3-wire. Just a thought.

[57taskforce]

Originally Posted by MARKDTN

Why do you want a 1-wire? They work great in equipment that cranks and runs all day with minimal accessories but not as nice in a vehicle with variable amp draw. I would wire it as a 3-wire. Just a thought.

I agree. The 1 wire doesn’t charge as well at lower rpms.

[68bowtie]

From what I’ve been reading I think it will work well for my application as long as I add a good ground. I have a 6-ga for the 1-wire to battery cable, and I don’t have many accessory loads. I like that it’s simple and easy.

I still haven’t found if there’s a way to have the amp gauge functionality.

[weq92f]

Originally Posted by 68bowtie

From what I’ve been reading I think it will work well for my application as long as I add a good ground. I have a 6-ga for the 1-wire to battery cable, and I don’t have many accessory loads. I like that it’s simple and easy.

I still haven’t found if there’s a way to have the amp gauge functionality.

I've got 1-wire that is doing better after rewiring all the amp draws to a single point and then attaching the alt lead to that point. I used 6 GA positive and 4 GA ground to BATT ( It's what I had ).

-klb

[dmjlambert]

Originally Posted by 68bowtie

I still haven’t found if there’s a way to have the amp gauge functionality.

You can have amp gauge functionality if you do these things:
1. Like weq92f, wire all the amp draws to a single point and then attaching the alt lead to that point. In the stock configuration, that single point would be a tape-wrapped joint near the driver side headlight. Those wires may be 12 gauge or fatter.
2. From the mentioned single point, connect one of the amp gauge wires with inline fuse.
3. From the mentioned single point, run a 5.5 foot 12 gauge wire to the junction by the battery. Connect the battery to that junction, and also connect the other amp gauge wire with inline fuse to that junction.
4. Do not connect any accessories to that junction, or to the battery, or to the starter lug. If you do, the current draw of those accessories will be invisible to the ammeter.

You can change lots of wire lengths and sizes in your electric system, but this one wire that runs from the alternator tie-in junction by the driver side headlight to the junction by the battery is 5.5 foot 12 gauge, it's part of the ammeter design. In reading on the forum about major customizations people do to their truck electrics, it seems to me not many people preserve the amp gauge during those customizations, they switch to volt meter instead. The amp gauge would not be compatible at all with the wiring shown in the diagram in the first post above.

[68bowtie]

Originally Posted by dmjlambert

You can have amp gauge functionality if you do these things:
1. Like weq92f, wire all the amp draws to a single point and then attaching the alt lead to that point. In the stock configuration, that single point would be a tape-wrapped joint near the driver side headlight. Those wires may be 12 gauge or fatter.
2. From the mentioned single point, connect one of the amp gauge wires with inline fuse.
3. From the mentioned single point, run a 5.5 foot 12 gauge wire to the junction by the battery. Connect the battery to that junction, and also connect the other amp gauge wire with inline fuse to that junction.
4. Do not connect any accessories to that junction, or to the battery, or to the starter lug. If you do, the current draw of those accessories will be invisible to the ammeter.

You can change lots of wire lengths and sizes in your electric system, but this one wire that runs from the alternator tie-in junction by the driver side headlight to the junction by the battery is 5.5 foot 12 gauge, it's part of the ammeter design. In reading on the forum about major customizations people do to their truck electrics, it seems to me not many people preserve the amp gauge during those customizations, they switch to volt meter instead. The amp gauge would not be compatible at all with the wiring shown in the diagram in the first post above.

I think I understand. Are the two "amp gauge wires" the yellow arrows below? Is the 5.5-ft 12-ga wire the one with the blue arrow?

[HO455]

Yes.

[68bowtie]

Excellent thanks everyone. I see why the amp gauge won’t work with my configuration.

[insidedev]

Originally Posted by dmjlambert

You can have amp gauge functionality if you do these things:
1. Like weq92f, wire all the amp draws to a single point and then attaching the alt lead to that point. In the stock configuration, that single point would be a tape-wrapped joint near the driver side headlight. Those wires may be 12 gauge or fatter.
2. From the mentioned single point, connect one of the amp gauge wires with inline fuse.
3. From the mentioned single point, run a 5.5 foot 12 gauge wire to the junction by the battery. Connect the battery to that junction, and also connect the other amp gauge wire with inline fuse to that junction.
4. Do not connect any accessories to that junction, or to the battery, or to the starter lug. If you do, the current draw of those accessories will be invisible to the ammeter.

You can change lots of wire lengths and sizes in your electric system, but this one wire that runs from the alternator tie-in junction by the driver side headlight to the junction by the battery is 5.5 foot 12 gauge, it's part of the ammeter design. In reading on the forum about major customizations people do to their truck electrics, it seems to me not many people preserve the amp gauge during those customizations, they switch to volt meter instead. The amp gauge would not be compatible at all with the wiring shown in the diagram in the first post above.

Hello,
someone has a video of a working AM meter here.

How strong is the deflection from the pointer if it works?

[LockDoc]

Originally Posted by insidedev

Hello,
someone has a video of a working AM meter here.

How strong is the deflection from the pointer if it works?

In all of my meters that work the maximum deflection is about 1 needle width in either direction from center.

LockDoc

[insidedev]

Thx @LockDoc,

but that's not very much .


I tested my once with an 18 gauge wire in the circit, because the display turned out a lot and well.

[LockDoc]

Originally Posted by insidedev

Thx @LockDoc,

but that's not very much .


I tested my once with an 18 gauge wire in the circit, because the display turned out a lot and well.

The 2 fuse holders in the circuit sometimes get corroded and keep the AMP gauge from working correctly.

LockDoc

[KQQL IT]

Originally Posted by 57taskforce

I agree. The 1 wire doesn’t charge as well at lower rpms.

Mine is 14.4 at 1000 rpms with a giant alternator pulley.
Weird

[HO455]

Originally Posted by KQQL IT

Mine is 14.4 at 1000 rpms with a giant alternator pulley.
Weird

The problem is at an idle. The voltage regulators used inside a one wire alternator won't allow charging (or only a very restricted output. There are different versions and manufacturers of regulators used over the years.) if the RPM is too low. At the time it saved GM money. And when the alternator wasn't running it was disconnected from the battery so there was no drain on the battery. The alternator is off below around 350 to 450 rpm at the alternator.
What this means at an idle it is basically a trickle charger. So at night, in the rain, during winter, in stop and go traffic your battery slowly goes dead. This didn't bother GM until they started to put serious computing power in the ECMs. Suddenly having a voltage drop became a much more serious issue. That's why all the newer alternators perform so much better.

[RichardJ]

I could not find the exact same image from post #1 on this thread on the Painless web site.
Another image with the same wiring with #915 & #916 shows them entering the fuse box separately.
I could not find an actual schematic of the fuse box to see why they sometimes used separate inputs in this fashion. Separate inputs could be used for Switched and UnSwitched circuits, but not as part of the charging circuits.
The image above failed to indicate the 8 gauge wire as their #960 wire.

Painless offers charts that help identify wires by assigned numbers.

They identify #915 as Engine Section - Alternator B+.

They identify #916 as Engine Section, Single Wire - Bat Positive or Start Solenoid.

I think what painless does, is provide wire for various configurations and if you don't use all of them, you just tie them together. Oh well, what do their customers know?

[RichardJ]

It took me forever to find this on their site as they seem to want to push people into using a one-wire Alternator.

This is for a three-wire Alt connection.
They use a #995 wire to connect the Alt terminal #2 to their #916 wire and #914 wire for the exciter connection.

It still doesn't explain why they are using the #915 as the alternator output as opposed to their #960 in their other drawings.

In https://www.painlessperformance.com/Manuals/10104.pdf they tell you how to add a resistor to the #914 and also how to add a Gen idiot light.

Now this Painless pdf. is impressive, but you better sit down with a serious adult beverage.

In this drawing, they should have the Midifuse as close to the Battery as possible and forget the starter as an alternative.
The #995 should be connected directly to the midifuse and not the #916 at the fuse block.
#995 is the Sensing wire. It carries very little current, but tells the voltage regulator and alternator, what the battery needs. It does that best by looking directly at the battery.