I'm in the process of switching to an alternator in my '56. It's pretty straight forward but I had a question on wiring on the alternator itself.

I've been following this guys how-to:

GM current for your Ford

What I'm confused about is why the pigtail from the #2 spot has to be attached to the bolt on the back where the wire that connects it to the battery goes.

The back of the alternator:



Wiring (the black wire should have a white line, whoops):


Also is "R" the same as the "#1" spot? Is that port (hard to see on the picture, but there is a male connection sticking out from it) with the nut surrounded by the black the same thing or something different? I ask because he mentioned connecting the black wire to the #1 but had it as "R" too and I didn't know if they where sepperate, even though it's clear it was the same on his, I just didn't know if it was something apart on mine.

And does the wire from the #2 port need to be 12ga or can 14ga work? (not sure why at this point it needs to connect down below, unless it was just to connect the plug's loose end.)


I didn't come across anything with running that pigtail there, I just was curious as to why before I did or didn't put it on. Probably a "well duh" question, but it's been way too hot lately and it totally kills my reasoning when I do electric, lol.
Thanks.

 

Use the big bolt at 4:00 for the ground. Here's something I found that should clarify the rest:

The 10SI has three terminals (including those with a 1 wire regulator).

The large "BATT" terminal which gets connected to your battery positive. (Or Terminal Post if your vehicle is so equipped).
And a dual terminal connector. (Repair pig-tails for this connector available at any autoparts store. Or, salvage with alternator if pulling the alternator from a vehicle).
The #1 Terminal. (Marked with a "1" on the case)
This terminal is used to connect to the dash warning light.
For the warning light, a lamp is wired in series with a switched voltage source. During normal operation the lamp stays off. If the regulator is damaged, the #1 terminal provides ground, and the warning lamp will light. Usually.
This terminal is also active on 1 wire regulator equipped 10SI alternators.

The #2 Terminal. (Marked with a "2" on the case)
This terminal is used to excite the 10SI into operation. (3-wire 10SI)
It is connected to the battery positive.
For simplicity you can connect the #2 connector pigtail directly to the "batt" terminal on the alternator.
The terminal is present on 1 wire regulators. Used only for those that require the stock connector to fit snugly.
If you are converting from a 3wire 10SI to a 1 wire regulator you can hook up all your stock connectors, and run it as is. However, thats wasted money unless you plan on cleaning out some wiring under your hood.

 

Thanks for the information, helps to know what things do to figure out anythign later on.

 

Oh, I'm a bit sketchy on the battery light warning, I haven't come across anything it's wired to inbetween, from what I can see it looks like it's wired from the generator regulator to the starter relay to the light. If it still stays on, where should I look? (I've checked all the wiring under the dash, best I can tell it's wired correctly)

And I'm converting to an alternator, I've been using a generator but after testing everything else, the battery light still stays on.

 

You need a special bulb receptacle; it can't have one side grounded like a regular lighting bulb. It has to have two wire leads, one that connects to #1 terminal, the other connects to switched battery (i.e., ignition switch). When the alt is not putting out anything, power flows from the switch thru the bulb to the alt (ground) and is lit. When the alt is charging, there is the same voltage on both sides of the bulb, so it doesn't light.

 

That's not the right flow - and it will be the same for both alternator and generator.

From your "Batt" post of your generator regulator (or the "Batt" post on the alternator); to the "B" post of the headlight switch; through the gauge/light; then out to the starter solenoid. Mentioned this in your other post yesterday. A to B to C. Just that simple.

 

Oh I gotcha, I was thinking something other than a light or ignition switch. Must be something inside the alternator that kicks off the connection, always wondered how a battery light would work (never really thought about it, just seemed like if the battery was dying it shouldn't be lighting anything up, lol). Been one of those days, working when it's way too hot and in the sun doesn't help my thinking process.

Thanks.


And either I'm missing something or I have no gauge... never seen a battery gauge, just a warning light. (this is about when someone just points at it and I hang my head)


Engine temp gauge - Oil warning light- odometer - battery warning light - fuel gauge

 

Semantical faux pas on my part. I figured you would be paying attention to the wiring flow and not pondering on whether or not it's a gauge or a light - figured wrong.

IT DOESN'T MAKE ANY DIFFERENCE!

To get this to work right you need to run the wires the way I told you to run them - four times now.

Run a 10 AWG yellow wire from the "BATT" post of the alternator (or generator regulator) to the "B" post of the Headlight Switch.

Then run a 10 AWG yellow wire from the "B" post of the headlight switch to the left wire on the Battery Warning Light INDICATOR.

Then run a 10 AWG yellow wire from the right wire on the Battery Warning Light INDICATOR to the Starter Solenoid post that has the positive battery cable hooked to it!

Leave the yellow wire running from the headlight switch to the ignition switch there. And make sure there isn't another wire supplying power to your ignition switch. Just that one!

 

10 gauge to/from a 5 W light bulb?! uh-uh. The indicator is not in the path for alternator output. That is from the big red terminal on the back of the alt to the solenoid or whereever the main distribution point is. The indicator wiring is fine at 18 ga. This is the typical 10SI pigtail.

If the truck had an ammeter, then you would wire to/from it with 10 ga. from the big red terminal

 

Thanks Ross, answered all I need to know on it on your first post, lol.

 

Unfortunately it doesn't make any difference if it's an alternator or generator at that point - 40 amps of electricity is 40 amps of electricity. And a 5W bulb may be caplable of taking that kind of electricity if it's designed to withstand up to 40 amps of the OEM Ford Generator built onto the truck (But you are right, it may not withstand the 70 amps that GM alternator will put out - what's wrong with those 1956 Ford engineers to have not anticipated that?). They use 5W light bulb on 480 volt circuits on airplanes. All the 5W indictes is the amount of heat will be generated to produce the light it needs to shine at a given number of lumens (brightness). Apples and Oranges, and completely irrelevant.

Also, on the OEM Ford wiring scheme for this truck, all that amperage from the generator regulator (or from an alternator) hits the distribution point PRIOR to being passed on through the light. The battery is a peripheral on a Ford not the main source of power as it is on a GM vehicle. So the generated amperage required and being sensed by Generator/alternator regulator is all being funneled to the sources (lights, ignition, etc) not to the battery through the light. So the light never sees that many amps - just senses flow direction.

The OEM wiring diagram shows that wire running through the "Indicator." So either this light here is not OEM (and I think it is), or if it is, and it is designed to take the juice - as the system was designed. Who knows? It wouldn't be the first time Ford documentation wasn't quite "Right." Maybe the guy drawing out the wiring diagrams that day was Penn Dick after taking his Ambien or something (just teasing you PD)

I do like your drawing and your charge flow though Ross. It's simple and it works. I'm assuming since it isn't labeled, that square right under the DC-10 is the headlight switch since it is his power distribution point on this 56. So with the exception of the light wiring, and the missing starter solenoid - that charge circuit is the same. Those two differences are the main differences between Ford style and GM style wiring. And frankly, GM charging is much easier to follow.

It's the power distribution that is a challange with a GM set up in a Ford. Normally when one installs an alternator, they put in fuse blocks for distribution to support the differences in flow. It's going to be interesting to see how your headlight switch with it's circuit breakers designed to handle 40 amps will handle 70. Or how your electrical stuff will all last without circuit protection if you bypass the headlight switch - or for that matter how you are going to distribute the power to them at all.

We'll see how this works. I hope it does.