Downside (or Upside) of 1-wire versus 3-wire Alternator???

james singleton

Well-known member
I am curious as to any thoughts/comments concerning the use of a "1-wire" alternator versus the use of a "3-wire" alternator. Is there much difference such as longevity of the regulator, etc.??? Thanks, James
 
Thanks Wallaka, that was a great article on both the "one wire alternators" and the "three wire alternators" systems. That article was just what I was looking for; it answered most of the questions I had concerning the two systems. Thanks, James
 
...but not mine.
May cont to peruse the search but...I'll drop this for now

Want the ford 3G for the 250 below. Need to slide by the heater hoses & tuck in for the Vi finned alloy VC,
Should be a 'small case', have tabs at 180* (12 & 6 o'clock), mount on driver's side. May B destined for the on board welder (300 amp/watt/volt whatever) but boss just wants it back out in the weather ("Get that junk oudda here, need access to the lift behind!"). Any 1 know if a tarus or other fits this bill?
 
I ran a 1 wire Power master with no problems. After you start the car revving it to 1200 rpms was no big deal. It is just a tap on the pedal and the regulator wakes up.

Now I switched to 3G. But it is still converted to a 1 wire.
 
i don't have your money... got mine (short)
:rotfl:
 
I am curious as to any thoughts/comments concerning the use of a "1-wire" alternator versus the use of a "3-wire" alternator. Is there much difference such as longevity of the regulator, etc.??? Thanks, James
Long ago I bought a 10Si self-exciting unit for mine (it's a single wire alternator) after finding out that the stock alternator was not working. You do have to rev the engine a bit to get the regulator going but it doesn't need an obnoxiously high rev so it's no biggie. I really like the simplified wiring and the fact that my ammeter now works much better with the update. As far as longevity, I've had a similar alternator in past cars and never had an issue with one.
 
By the way there is a simple solution for this, if you will put in the correct resistance Alternator Charging Indicator Light Bulb into the Circuit then you won't need to Rev the engine and it will be charging as soon as it's started at idle RPM's.
 
"...longevity of the regulator, etc.?..."
not certain - now it's up on the alternater itself is there less heat? I doubt it, ina smaller package, digital not analogue? etc. I don;t know. Once uising the 3G I plan ona huge wire + a megafuse (175). I ordered one w/a 7.5 inch square case. Many havea 9, 9.5 inch square case. Not sure this has the typical 3G back (C if I can post up here):

FORD 3G ALTERNATOR

Typical Installation

page1image4225622544
 
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guess so. Boy that's huge. (now U no Y I am not a pic poster). Wanted to cite Chuck A. @ BCB bronks as a real resource for all things bronk (40 yrs now, a move frm Cali to TX 1/2 way thru that time) for the above schematics.
I think I'd better use the "hide-a-solinoid" method as removal seems a bit tricky. I just wanna buy some time, get back on the rd, B4 deciding abt the on board mig (300 amp alternator?) a few yrs down the road. Still not learnin alot bout automotive electrics. I must have a real block. Cant teach an ol dog new tricks? aahahahaa
I think the above (1990s? same in '00s?) isa 90/130 A. @ idle 90 ... w/revs above (1, 1.5K) it develops the 130A. It has the 180* or opposite side mount tabs (like oe). The newer U go the bigger the case it seems. My H.Hoses'n header flange, the VI finned V/C all come into play for common real estate. We'll C when delivered...may need to test several ....... 8^ (
 
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Guys, FWIW I have been running a Tuff Stuff 1-wire 100 amp unit on my 300 that is great. It is 1/4" longer than the factory case, otherwise stock dimensions and mounting. It's best feature is the very low RPM it kicks in, and stays in. At 750 rpm it puts out enough amps to support AC with 2 radiator fans and dash fan on high. $123 at Summit. The PN for the V-belt is TFF 7068. They have serpentine belt units also. I like the clean, one-wire look over the factory wires running here and there.
A small US outfit in Ohio, US made.
 
Tuff Stuff is great (usa made +). Expensive (for me) and not 3G (as above schematics). Dont mean "no good" tho~
 
The the 3 wire is the way to go. "The 1-wire alternator is self-exciting, it requires the driver of the car to exceed an engine RPM threshold to tell the alternator to start charging. It does not start charging until it reaches a threshold RPM – which requires the engine to rev up a bit." “The 1-wire alternator only has a sense of what it is sending current to, which is the battery. If the battery is up, it does not recognize a voltage drop. The three wire alternator senses voltage at the fuse block and the ignition, and the alternator will then charge more to get all the systems up to power,”
 
"...to exceed an engine RPM threshold to tell the alternator...
& that can be as low as 1,000 RMPs for some, no?
 
Some people want the alternator to charge below 1,000 rpm. For example running a wide band air-fuel ratio meter that doesn't begin heating the O2 sensor until the voltage reaches 12.5 volts.
 
Something I encountered last year on a particular styled rv. There is some realization of what our alternators do actually is much less compared to what we expect of them. This is a programable regulator that you set per your battery profile. It is much more prevalent for the inboard marine engines.
 

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The the 3 wire is the way to go. "The 1-wire alternator is self-exciting, it requires the driver of the car to exceed an engine RPM threshold to tell the alternator to start charging. It does not start charging until it reaches a threshold RPM – which requires the engine to rev up a bit." “The 1-wire alternator only has a sense of what it is sending current to, which is the battery. If the battery is up, it does not recognize a voltage drop. The three wire alternator senses voltage at the fuse block and the ignition, and the alternator will then charge more to get all the systems up to power,”
No harshness or contention intended, but this is not correct. The 1-wire alternator I am running charges MUCH better than ANY factory alternator of any brand I've ever run in 48 years of driving. Perhaps it's just the brand (Tuff Stuff), their selling point is the low RPM amp output due to the coil windings. At 750 RPM the alternator keeps up with a 50 amp load. It begins charging the moment the engine fires, and never has less output than the amp demand above 750 rpm. It's very impressive, and I will not be returning to a factory-based external regulator system again.
 
some dont make a destinction btwn "1-wire" and "3G".
Nother forum I saw a good deal of jaw boning re: starter solinoid (ford's fender mounted) and the use of the term 'regulator' for same item. I think the words used w/precision (nouns) can help alot. Fella may confuse 2 (& in some cases 3) items w/"solinoid" if not attending to language as in starter's solinoid/relay (fender mount) and the starter's solinoid (pmgr's on the starter itself). Would this help in the above? - '1 wire' and '3G' ? (I state again - auto ele is a mystery 4 me, learnin from U guys tho).

seen the marine "78" posted? programable
 
No harshness or contention intended, but this is not correct. The 1-wire alternator I am running charges MUCH better than ANY factory alternator of any brand I've ever run in 48 years of driving. Perhaps it's just the brand (Tuff Stuff), their selling point is the low RPM amp output due to the coil windings. At 750 RPM the alternator keeps up with a 50 amp load. It begins charging the moment the engine fires, and never has less output than the amp demand above 750 rpm. It's very impressive, and I will not be returning to a factory-based external regulator system again.
No mention was made of an external regulator nor does 3 wire mean an external regulator is used. The difference between the ONE-WIRE and THREE-WIRE alternator is the voltage regulator. The Delco part # D680 voltage regulator is used in both the 10SI and 12SI THREE-WIRE models. The same model of alternator can be assembled with different types of voltage regulators (for ONE-WIRE or for the THREE-WIRE system).
The subject is more complex than just charging the battery. A lot depends on how the vehicle is wired. A sensor wire can adjust the voltage at the load point instead at the the battery.
The other of the two plug-in wires at the SI series alternator is the “voltage-sensing” terminal for the voltage regulator. Through the sensing-wire, the voltage regulator monitors electrical system voltage and makes adjustments to alternator output. The regulator will adjust alternator output as needed to maintain the place where the sensing-wire is routed (at about 14.2 volts). And the sensing-wire can be routed to a place remote from the alternator (downstream).
This “remote voltage-sensing” feature is often a big advantage when running with a factory type wire harness from the Muscle car period (60’s and early 70’s period cars and trucks). Then the alternator output will be adjusted according to what goes on far downstream from the alternator–at the main power distribution junction, which operates the whole car plus charges the battery!
The 12SI Delco alternator is a very good up-grade. With a diode, 7/16" drill bit and a 1" spacer it will bolt right on a 200 Ford six.
For most applications, the advantages of a THREE-WIRE alternator will far outweigh the little time saved with a ONE-WIRE installation. 3 wire vs 1 wire alternator.JPG
 
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