1 wire or 3 wire alternator

[tolobill]

hi, new guy to the pirate have a 80cj7 with 78 302 want to get rid of voltage regulator. is it possible to get a list of parts to convert to 1 wire or 3 wire alt and which is better. i looked thru lots of pages on search cant find, be nice thanks.

[Gummi Bear]

Hit the Bronco sites, and start doing research on 3G alternators. There's some great tech on them. Stick with the 3 wire. It's not that complicated, and doesn't rely on one thing only to cause excitation.

Here's where you can get some plug-n-play parts to make the conversion, if you're wiring impaired:

http://fordfuelinjection.com/?p=67

[mooktank]

Grab a delco si series. It's easy as pie to run a 3 wire. I have a 21si for sale right now as a matter of fact. It's reconditioned and rated for 150 amps.

[DRKelly]

Originally Posted by mooktank

Grab a delco si series. It's easy as pie to run a 3 wire. I have a 21si for sale right now as a matter of fact. It's reconditioned and rated for 150 amps.

x2

Except I think he meant to say 12SI.

[RRRAAAYYY2]

If you want to go one wire, we make an almost bolt in, need a 1" spacer on the pivoting (spool) mount. Not hard to do, can use washers if you had too. Some of the advantages to our units are that compared to the "si" Delco alternators they produce a lot more at idle. We make them in 130amp, 170, 200 amp models.

The 3G isnt the best in a one wire application, they have yet to fully perfect the regulator for it. So you are stuck with it being a 2 wire alternator, one to the battery and one to a light/ignition circuit. It is a pretty easy conversion to do. Advantages of the 3G are it will produce really good in the bottom end, and it can handle mud a little better.

As for what is better one wire or externaly excition (2-3 wire). The only disadvantage to a one wire is it places a .03amp draw in your system. The older "si" units also need a high rpm turn on as well. But other than those two things, one if you are using a newer style, one wire is superior to the extra wires. i.e. one wire senses internally, whereas the wired in unit has to rely on the lamp, lamp wire, lamp feed, sense wire, as well as the alternators internals, just lots more stuff to go wrong.

[mooktank]

No I have a 21si. Not a 12si. It's a big unit but is nice and makes good power.

[RRRAAAYYY2]

The 21si would make way better power than the automotive 10 and 12si. Internally it is very similar to the CS144, except it has a longer rear bearing, except in the AG units.

What mount is yours? Do you have a spool mount where there is just one bolt through the bottom, or does it have the J180 with the two mounting ears on the bottom?

[Wicked_S10]

The advantage to haveing a 3 wire altenator is that it senses voltage at the main distribution node for the electrical system, which should not be at the battery. On older fords and GM's the distribution node is typically the starter solenoid. On a 1 wire alternator, the voltage regulator gets its input directly from the charge wire, which will always be higher than down stream/after the battery. This means that a one wire alternator is not doing as much for your chargeing system as a correctly wired 3 wire alternator. It takes a pretty major power draw to effect the voltage upstream of the battery. IMO the only benefit to haveing a 1 wire alternator is that they are easier to install with less engine compartment wire/clutter. The 3 wire alternator will provide the better performance when wired correctly.

Later,
Jason

[RRRAAAYYY2]

What better place to have a discussion about this then on a Ford thread. Fords have been forever plagued with over voltage problems, especially late models, because of issues trying to sensing externally.

A perfect charging system would have the alternator go directly to the battery, then from the battery to a distribution block, then to your loads. The battery has two major functions, the first is to store energy. The second is to asorb voltage spikes in the system. The biggest contibutor of voltage spikes is the alternator. But this is getting off topic.

The alternators regulator works by turning itself on and off, sometimes up to 333 times in one second. When it shuts off it checks the voltage in the battery. Whether it is external sense or internal sense. So the optimum system will have the shortest distance, with the least amount of possible resistance in it. That has to be/should be internally, down the main charge wire, to the battery. Since it is a reference voltage with little amps, the main battery cable should almost always be the best route.

When you force the refrence voltage to come from a long distance, through smaller wire, you introduce lots of places for the reference voltage to be altered. A good example would be in 6G equipped vehicles. About six inches from the regulator the plugs are notorious for building up resistance in the fusable link in the wire. This causes the alternator to get a false reading, which causes it to over charge.

An even better example is when GM first introduced the CS130's in the late 80's, many of them came with two wires in the regulator. On was the "L" indicator light, the other was external sense. After about 1993 when our customers complained of an over charging problem in a GM application, we would ask if it had a thicker red wire going to the regulator. 9 times out of 10 it did, and cutting it solved the problem.

Chrysler and Ford are the only two manufacturers that havent changed from the external regulators. Most everyone else stopped using them in the 60's as technology progressed.

The big thing is remembering how the regulator functions, and what it is supposed to do. It reads battery voltage, and adjusts how long it needs to stay turned on to bring the battery voltage back up to a predetermined set point. It is not reading the voltage in the system, just in the battery. If it was reading the system voltage, and it corrected its output to a distance a long way (voltage drop) away from the battery, it would then over charge the battery.

Hope all this makes sense. If not I can try explaining it another way.

[Proeliator]

This is a good discussion. To be honest, I was always adamanent about sticking with a three wire alt. However, a couple years ago I ended up going with a high amp, drop in, one wire in both the hiboy and the eb. I've been happy with both and sold on the one wires now...I'm a big fan of the kiss principal.

[RRRAAAYYY2]

As much as I like them, I wouldnt recommend a 3G one wire yet. We havent found a good regulator, as in durability yet. Tried another new one today, cut in awesome, but wouldnt shut off. It was in an alternator meant to charge hard at idle, and that might be why it wouldnt shutoff. I am just sckeptical of them as for three years we have been trying different brands, and revisions, etc. Usually they dont turn on worth a crap, these new ones are good for that. Going to test it in a regular alternator next week.