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I'd like to upgrade my alternator to 140 amps. Been looking at different ones from Powermaster and others. I'm confused with the "1 wire compatible" descriptions on them. I have the stock 3 wire connector. So what's the scoop on these, do they all work?
I swapped to a powermaster 1 wire a few years ago. It works awesome. It powers all my electronics. My car has massive dual electric fans/EFI and all the other usual stuff. No issues w amperage/voltage. I have a wire going from the battery to the alternator, that's it. Just make sure the belt is good, it takes more to turn it vs a stock unit.
Can also look into an AD244 LS alternator swap if you have a serpentine setup. It's been documented on this site and I've also personally done it on mine.
At which point you can run a factory 140 amp alternator.
Can also look into an AD244 LS alternator swap if you have a serpentine setup. It's been documented on this site and I've also personally done it on mine.
At which point you can run a factory 140 amp alternator.
I believe I saw that but it looked to be an 88 or later where the alt was on the passenger side. Mines an 87.
Alternator Technology has improved greatly since the 1980s.
Our original Alternators (and a direct replacement) have rather poor output at Engine Idle and Low-RPM.
More Modern Design Alternators do a far better job (such as an AD230 or AD244 Model GM Alternator).
Newer and better technology is available as a "bolt-in" Solution.
Why use outdated Technology when replacing the Alternator?
Greater efficiency and Low-RPM Output has been available for a long time now.
Alternator Technology has improved greatly since the 1980s.
Our original Alternators (and a direct replacement) have rather poor output at Engine Idle and Low-RPM.
More Modern Design Alternators do a far better job (such as an AD230 or AD244 Model GM Alternator).
Newer and better technology is available as a "bolt-in" Solution.
Why use outdated Technology when replacing the Alternator?
Greater efficiency and Low-RPM Output has been available for a long time now.
If I'm at the parts store looking for my alternator replacement in this upgraded spec, what am I asking for? @vorteciroc
I always thought "1 Wire" alternators were for tractors, farm equipment, and industrial engines. Oh and old timers too ignorant to wire up a 3 wire alternator.
An alternator (leaving aside the PWM ones briefly, which once you understand the fundamental principle, are not so strange after all) has 3 wires.
Wire #1 : connects its output to the battery, to charge it, and to power everything else. (duh) That's the only one a "1-wire alt" has.
Wire #2 : tells the alt that it's time to be charging now. I.e., the key is on, the engine is running, the rest of the electrical system is up and running; etc. In cars with an idiot (sofakingdom) light, it also lights the light. Which leads to interesting situations if the light bulb burns out.
Wire #3 : the "sense" wire. The alternator does all within its power to maintain the voltage at that particular point in the system, wherever it is connected to, at some predetermined level. Think of it as the alt's "eyes" into what it's supposed to be doing. There's a "regulator" somewhere that varies the alt output to make this happen. In the old 60s version the regulator was a separate piece and usually mounted to the radiator core support. In these cars it was inside the alt.
Alternator "amps", beyond that, is all about how much current the alt can deliver under any given conditions. (RPM, temp, etc.) It will attempt to deliver however many amps it takes to keep the voltage at the point where wire #3 is connected, at the regulator set point. (usually 14.2 - 14.4V or thereabouts) A higher "amp" alt will maintain that voltage when more current is being demanded.
A useful analogy is, a water pump. Voltage is pressure; current is flow. If your pump isn't big enough, then when you turn on too many faucets (try to take a shower and run the washy sheen at the same time) and the pump isn't big enough, then when you flush the toilet the shower turns from a splashing squirt into a pitiful dribble, and the washing machine only fills up halfway, and you can't get enough water out of the sink to fill your water glass. Pretty simple.
A "one wire alt" hooks its "one wire" as wire #1 above. It does away with wire #2 by making an internal connection that doesn't drain the batt too terribly much if the engine isn't running. It does away with Wire #3 above by hooking the batt DIRECTLY to the "sense" point (regulator input), which is the batt terminal.
So, consider a REAL WORLD car. You have the alt out there somewhere, all charging up the batt and stuff, butt then you have this WHOLE CAR THING to deal with. Well, every inch of wire, every connector, every fuse, every switch, every EVERYTHING that the 12V has to go through AFTER it leaves the batt in order to reach your amplifiers and headlights and whatever all else, passes through all that. Every single one of those little details LOWERS the voltage reaching the device you'd REALLY like to be fed the highest possible amount of juice. Like maybe, the fuel pump. Could be anything; whatever is most important in YOUR car to YOU. YOU get to decide that, to some extent.
In a perfect world then, you'd hook wire #1 to the batt (duh), and assure that the path from there (the batt) to The Most Important Electrical Thing in YOUR car has as little resistance as possible (large wire, few connections, few switches, etc.), and maybe use some sort of VERY RELIABLE fuse such as a fusible link, to "blow" in case something really terrible happened, because IT SUCKS to have your car burn down for an electric overload.
You'd hook wire #2 to some point in the system that the alt can easily recognize as "oh, time to charge, oh, time to go COMPLETELY to sleep and draw no current whatsoever" to some sort of ignition (key on) source; keeping in mind that it MUST be current limited, so that the alt can't burn itself up trying to power the whole vehicle through it. All that's REALLY needed, is "excitation" current, which is well under 1 amp.
Wire #3 would go to THE ONE MOST IMPORTANT PLACE that you want to keep the voltage constant at. Might be your amp, might be the central distribution point (fuse block bus), might be ... ANYWHERE. Being the brilliant ape you are, YOU, if you're designing the car, get to pick that place.
Not so hard, really. Not hard to see why a "1-wire alt" is TERRIFIC for a stationary generator, or a pump, or a winch, or any of THOUSANDS of other applications for alternators OTHER THAN a "car": in those other applications, all the alt has to do is charge the batt, NOT run all that other stuff. Having the "1 wire" setup also means it's DIRT SIMPLE and highly reliable, in that sense. The least possible amount of stuff to break, the least amount of wiring. Not hard to see though why it's TERRIBLE for a "car" where there's so much more going on than just making sure the motor starts next time.
In a ski boat for example, you'd hook wire #1 as close to the batt as you could (maybe at the starter Big Lug), wire #2 would be hooked to ignition through a light bulb and/or a resistor, such that maybe 100 milliamps up to 300 milliamps would be fed to the alt when the ign is ON (that would require a resistor in the 15 - 50 ohm sort of range, butt 100 ohms would probably be "enough" to get it going), and wire #3, THE MOST IMPORTANT ONE as far as its location, might go to the 12V bus of the fuse block.
THAT'S why a "1-wire alt" is inadequate. Typically, it will keep the batt charged, but the lights will get dim when you turn the blower to high speed, the gauges will move when the bass thumps, etc. etc. etc. Yeah, some guys might tell you "it works". And they're not lying, they're telling the "truth" as far as they can see it, they mean well. Yeah, a solar eclipse is caused by a frog eating the sun, and yeah we're terrified, and yeah, we have to beat on our drums to scare it away, and yeah, that "works", and yeah, yesterday, I'd only have had to beat my drum for around 4 minutes to drive the frog off. Yeah, the car might start reliably. Butt is it The Best Way to wire a car? NO.
A PWM alt is driven by a portion of the ECM that does the "sense" thing independently, and controls the alt output, by varying the proportion of the time that the alt is charging. So, if the batt is stone cold DEAD, or you have Hush by Deep Purple or some rap crap or whatever turned up to 11, it can make the alt produce 100% power 100% of the time. Or, if you're driving down the road with the headlights on, it can make the alt produce full power 10% of the time, butt it's so fast that you can't tell. Like, it's at high power for .01 sec, but then resting for .1 sec. Same principle, just, applied from a different "brain". The "regulator" is the ECM instead of its own little black box.
It's just electricity, and it's just a car. The electrical system in a "car" is about the simplest and eeeeezyest to understand, of anything. There's like BILLIONS of "cars" in the world; people of every culture, ethnicity, history, geographic location, etc., ALL seem to be EQUALLY capable of producing "car". I've been all over the world (well almost) and I've seen "car" built by EVERY SINGLE ONE and maintained by ALL of them. Trust me, if THEY (whoever "they" are) can do it, YOU can too. It's JUST NOT THAT HARD. Put aside the childish "I'm not good at [fill in the blank: math, science, wiring, etc.]" and GROW A PAIR (of brain cells) and decide for yourself that childish things must be put aside and YOU can do this too. It's JUST NOT THAT HARD.
Last edited by sofakingdom; 04-12-2024 at 06:52 PM.
My 1 wire powermaster works great. I've never used a 1 wire w a stock setup. What sofa says makes sense. My car has a standalone EFI, stand alone fuel pump wiring harness and fans wired in. It's all run from a junction block next to the battery. My voltage reading at the junction block is about 14.3 volts. Interestingly my autometer gauge cluster reads 14.8 volts. This is wired into the stock positive in the gauge harness (not gauge lights!). It would be interesting to check voltage further out (like a fuel pump) in a stock setup. I don't know that there would or wouldn't be an issue w a 1 wire in a stock car. I do know that the stock 82 60 amp unit wasn't cutting it. The 140 amp powermaster does the job well as long as the belt spinning it is in good shape. It also came in a very fancy matte black!
There are a bunch of options out there, most of which are better than mid 80s stock. It's all about what your goal is.
You know, that's an explanation that was a long time coming. Being in my trade for as long as I have (wires and stuff) and being in the automotive technology school system before that, I'd not known (or more likely not remembered) the 3-wire layout.
Neat.
Funny thing though. I rewired a good chunk of my latest ride and aside from the #1 wire, I've no recollection where the other two are landed. I've long since removed the charging idiot light too.
With a new distribution centre on the to-do list, this will be something that'll have to be re-visited. It might just explain some of the earlier charging system trouble I was having a few alternators ago.
Thanks Mr S.
does the one-wire alternator require a fusible link
Do you "require" a fire extinguisher in your garage?
Those questions are pretty much in the same ballpark. It's not so much a matter of "require", as, what are you willing to tolerate if things go REALLY sideways. Like, what are your wife / GF / children / parents / siblings / friends LIVES worth to you? Proper use of over-current protection is along those lines.
I bought a 3-wire stock replacement (140 amp) from Napa forever ago (10+ years), for my '83, still working just fine. Passenger side, set up for V-belts. Originally for a 76 K20. No clue if that is helpful or not, I've kind of lost the plot on this thread
Yeah, a solar eclipse is caused by a frog eating the sun, and yeah we're terrified, and yeah, we have to beat on our drums to scare it away, and yeah, that "works".
We usually skip the drums, , and go straight to tossing a virgin or two into the volcano to please the Sun / fire Gods, , , , seems to work for us....
My 89 had no circuit protection on alternator B+ cable.
There are many things about these cars that are ... shall we say ... less than optimal, ... in hindsight. Kinda like the old Frods that ran all steel fuel line EXCEPT FOR a carefully selected 4" section of GUARANTEED TO FAIL pressurized rubber fuel line right next to the dist, such that when the rubber dry-rotted, it DIRECTLY doused the dist in fuel, and ... guess what happened! Most newer cars are designed better than that, not least because warranties are MUCH longer these days than they were back then and liability insurance at the mfr level MUCH stricter. 70s and 80s American cars have some UNBELIEVABLY sloppy engineering in them. (as well as production, "design", and every other facet except "value planning") Just because they were crappy originally, doesn't mean that crappy is inherently "right".
No denying any of that. I was just trying to find out if my car was missing something that was originally implemented by the factory. Why? Because my car sat for 18 years with no engine, so when I finally got to working on it and putting it together, I couldn't always remember what was originally there. I was also curious to know if the one-wire alternators had a fusible link on the output wire but not the 3-wire units. But yeah, there are LOTS of things on these cars that could be improved over the original OEM design...
preach. The amount of parts held on (BY DESIGN) with self-tapping screws is bonkers.
I always pictured the assembly line being like “that goes somewhere on the inner fender, just zip it down round about that X that Billy put there.”
04-06-2024, 11:48 PM
