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Thread: One Wire (self energizing) Alternator?

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Posts: 1-10 of 16
2016-04-26 22:11:29
#1
One Wire (self energizing) Alternator?
I'm curious if anyone has swapped out the factory alternator with a One Wire model, and if so, what model worked and how you fitted it? Generally, the only people likely to have done this are people that track their cars, so I'm posting in the Road Racing forum.

The main benefit is simplified wiring, and not having to worry about accidentally burning out the alternator using the Kill Switch to stop the car.
2016-05-07 20:22:38
#2
I've not heard of these before, but now I'm curious as well.
2016-05-07 20:43:19
#3
Never heard of it, any links or general info? Pricing?
2016-05-08 02:55:48
#4
Ok, the general principal with a 1-wire or self-exciting regulator on the alternator is that it doesn't rely on battery voltage being present in order to energize the coils in order for the alternator to start producing electricity when it spins up. The regulator will then put out a fixed voltage once sufficient RPMs are made to keep the field going.

This means that there is no sense line going to the battery to help regulate output, and also there would be no charge light on the dash to tell you if the alternator was putting out power or not.

This is really only useful in race applications when the car has a kill switch, the kill switch will also usually cut the sense voltage line, so when you kill the car, as the alternator is still spinning the regulator thinks that the battery is at zero volts, and tries to ramp up the power during that brief time the alternator is spinning down as the engine dies. Depending on the design of the regulator, this will often result in the regulator burning itself out (maybe not today, maybe not tomorrow, but one day, when you least expect it...).

The 1 wire alternator eliminates that issue because there is only 1 wire connected to the alternator, the output line.
2016-05-09 01:09:08
#5
Being that we're going through alternators like hot knife through butter, I would be interested in knowing how this works out for you.
2016-05-09 16:17:48
#6
Originally Posted by metro_se-r
Being that we're going through alternators like hot knife through butter, I would be interested in knowing how this works out for you.


I've been doing a lot of research here. Short answer to my original question is that there doesn't seem to be an off the shelf solution.

From what I've read, no manufacturer ships a 1 wire alternator from the factory, with the exception of forklifts, marine applications, etc. Nothing you're likely to find in your local auto salvage yard. Some auto parts places will stock some of the standard GM type alternators with 1 wire regulators built in, but these aren't a bolt on affair.

So the next option is to convert the alternator to a 1 wire by replacing the regulator. This is a pretty simple thing, it involves removing the old regulator and swapping out with the new one. But the regulator is specific to the type of alternator, and I haven't had a chance to pop mine open to see what's inside.

Some googling for 'nissan 1 wire regulator' and similar searches hasn't come up with any reliable hits, I believe that our alternators were originally made by Hitachi, and they may not have offered such a regulator. So, I may be back to looking at retrofitting a more common alternator type that has an easy supply of regulators available, if I do move forward with this idea.
2016-05-09 17:30:05
#7
OEM Nissan alternators for our era are made by Hitachi or Mitsubishi.

The newer Nissan alternators are made by Hitachi, Mitsubishi, and Valeo.
2016-05-09 17:59:17
#8
Originally Posted by metro_se-r
Being that we're going through alternators like hot knife through butter, I would be interested in knowing how this works out for you.


Metro, are you burning out the regulators, or some other issue? I'd bet if you run the Sense wire directly to the battery, the problem may disappear.
2016-05-09 22:00:36
#9
While searching for some newer alternators that may fit to test with (newer Versa and Altima), I noticed that the pulley used on the newer ones was no longer a solid piece, and is instead clutch driven. An example of one of these is this model from a 2006 Sentra 2.5: 94117 HIIILR New Alternator | Product Details | Remy Auto Parts

Not having seen this technology yet myself, I was curious how this worked, and came across this video:

Now, the B13 doesn't have a tensioner like that engine does, but it's easy to see that the newer clutch type pulleys are a definite advantage. Basically as the engine accelerates, so does the pulley, but when the engine slows, the pulley keeps spinning through inertia (think how the clutch flywheel works) and keeps spinning the alternator faster than the belt is actually moving, then when the engine accelerates again it catches up with the clutch on the pulley and spins it back up again. These alternators may also be designed to spin faster because most of the ones I've looked up have smaller pulleys than what's on the B13.


This info is totally irrelevant to the 1-wire conversation, but it was cool information so I thought I'd share.
2016-05-10 16:45:00
#10
^^^THIS^^^^

Also of note, when OAD and one-way clutch alternators go bad they act as solid pulleys and exhibit the same noise and belt flutter. That is one way to diagnose a weird noise coming from your engine bay. Another way to tell is rev up the engine really high and shut it off while rpms are still high. If you don't hear a loud whine from the alternator as it spins down to a stop for a few seconds after engine stops then the OAD/one-way clutch is bad also.
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