Looking at  electricals in '72 Chevelle. while changing over to march pulley on alternator the nut on shank does not to many threads. Not sure if normal but not something I would trust. The snowball effect is coming read on. The old style external reg 10 g wire thing routed all over not to good given current draw is higher with electric fans and pumps.  
I called powermaster and getting a new alternator it is single wire and they reccomend wiring it single wire.
So I will keep the 10g back to horn relay disconnect the old reg. alt Hook 6-8g to batt and wire fans direct to battery with relays. Running 100A alternator and figure on 10A + 28A + 15A constant draw with fans going.


Anybody have issues with single wire. I did this to my '59 Impala and it works good.
Now I see where 3 wire is great where the sencing is back at the horn relay, but in a 72 the shortest path is back to battery plus I can hook fans , mallory box and maybe headlights with relay right there and not worry about driving high current all around with the 10g wire through the horn relay. I will have to check to see how the fuel pumps are wired in.  

Secondly, the battery cables looks like 4-6 gauge.  What size wire for 11:1 557bbc with 34-36 degrees lock out timing (it is always 34-36 degrees) you think would be good? 
Thoughts on this bigger cable more current can wack the strater to avoid kick back.

paln on + 1/0 to starter and - 1/0 to block 2 g or 1/0 to frame from block ground straps from block to body.  If this is too big lmk. + cable about 4' and - about 3' 

Anyone have any experience in alt swap want to share ideas and/or making battery cables if you ever did it ?

only trouble i had with one wire was with shut off switch for draigstrip. for some reason when you hit the kill switch on a one wire it kills the alternator or something like that. the alt. shop explained it something about it would need to be reenergized. all i know is it never charged right after the kill. don't know much about this except it never happened again after i went to 3 wire alt.

single wire is ON at certian RPM level ie at initial strat up it is off until Alt RPM reachs.
From PowerMAster website:
When to use a one wire alternator?


Powermaster early style Delco alternators will work either way - as a one wire or OEM style. The main difference between a one wire and an OEM is the method used to energize or turn on the alternator. An alternator using the OEM style is turned on with the ignition switch. The one wire design is energized with a special sensing cicuit built into the internal voltage regulator. This circuit senses the rotation of the alternators rotor. The rotor must turn at sufficient speed to trip the circuit, starting the charging process. This turn-on speed is affected by several things and is typically higher with certain high amperage alternators. Once this circuit is tripped, the alternator will charge at all speeds, even very low ones, until the alternators rotor comes to a complete stop. At that point, the circuit will shut off and wait for the process to be repeated. What this means for the consumer is that in some applications the engine must be revved to 1200 or 1400 RPMs to turn the one wire alternator on. If the wiring harness is available and this characteristic is annoying, then Powermaster alternators can be plugged in like the stock unit and operated with the ignition switch.

Now the 1200-1400 rpm is dependent on crank to alt pulley ratio they are assuming stock setup at 3:1 alt turns 3x faster then engine RPM of 1200-1400. My setup will be 2:1 with my idle around 1000RPM. After start up rev it up and it should turn on and stay on til you turn the car off again. I have an amp gauge in '59 Impala and noticed this when we first start the car AMP meter reads negative or 0 until I reved it up then Alt turned on and stayed on charging reguardless of RPM.

Did you mean yours actually stopped working for good when you hit the kill switch the alternator would never come back on ? it was completly dead or erratic ?

-- Edited by Bowtieman427 on Saturday 5th of March 2011 04:53:09 PM

yes it had to be replaced. it died, at least that was my understanding. maybe i was misled by alt shop but it all worked out. i never did understand it.

-- Edited by frank on Saturday 5th of March 2011 05:17:52 PM

You don't want to run your fans off the battery. All the battery is there for is to start the engine. After that ALL power should come from the alt. You need to wire the fans into the alt circuit with the relays and circuit breakers. You'll overheat and ruin the battery by constantly running power thru it.

-- Edited by Lost in the 60s on Saturday 5th of March 2011 07:59:55 PM

As for the battery cables. 1/0 gauge is perfect. You can't go too big on the battery cables.

Hey bowtieman I was reading your post on one wire alt. Im confused by all the extra wiring needed when all you need to do is unplug the stock voltage reg. hide or remove the wiring then run the appropriate size charge wire to starter HOT lug then the appropriate size wire from starter HOT to batt. Of course a good chassis ground is also needed. Now if you want to use the dash "CHARGE" light, different story, typically a one wire alt wont work properly then say hello to the three wire like stock with external reg. as far as "turn on" and "turn off" of alt I think of older one wire alts. Newer gm style one wire alts turn on and off with the fan belt and only supply output amperage equal to the amp draw on the batt at any given time. So long as you start with a good quality, fully charged battery. Oh yeah...... I dont see what difference it makes where you hook electrically powered accesories, to the hot side of batt, hot post on starter, junction block or wherever, as long as the power consuming  device is properly wired and fused

Pushrod wrote:

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Hey bowtieman I was reading your post on one wire alt. Im confused by all the extra wiring needed when all you need to do is unplug the stock voltage reg. hide or remove the wiring then run the appropriate size charge wire to starter HOT lug then the appropriate size wire from starter HOT to batt. Of course a good chassis ground is also needed. Now if you want to use the dash "CHARGE" light, different story, typically a one wire alt wont work properly then say hello to the three wire like stock with external reg. as far as "turn on" and "turn off" of alt I think of older one wire alts. Newer gm style one wire alts turn on and off with the fan belt and only supply output amperage equal to the amp draw on the batt at any given time. So long as you start with a good quality, fully charged battery. Oh yeah...... I dont see what difference it makes where you hook electrically powered accesories, to the hot side of batt, hot post on starter, junction block or wherever, as long as the power consuming  device is properly wired and fused

---

According to my electrical engineer friend, running the draw power thru another devise, such as the battery or starter solenoid, is a waste of power and the devise. If you think about it, why draw the power out of the battery forcing the alt to constantly recharge it. Bypass the battery and draw the power directly from the alt, which as you said, produces the necessary power for any/all needs on demand. The constant state of discharge/recharge is what wears a battery out. By removing it from the circuit, it recharges to full and then just sits there doing what it was designed to do.....store power until you need to start the engine again. By looking at the layout of the one wire alt circuits that GM went to years ago, you will see exactly that too. There hasn't been an accessory power wire coming from the positive terminal of a battery for over 25 years.

 

so where are you saying all the electric seats sliding doors, radio and door locks and all those other things are connected to that work when the car is off.

Try RUNNING your car without a batt or a dead batt then get back to me.

Pushrod wrote:

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Try RUNNING your car without a batt or a dead batt then get back to me.

---

When a car developes a charging issue, that is actually the fastest way to determine if the alt has died. Pull the positive cable off the bat, if the engine quits, the alt is dead. If the alt is good, you can run it on the alt alone till you wear it out. You absolutely don't need a battery in a running vehicle with an adaquate alternator.

And yes Frank, it's obvious that power accessories run off the battery when the engine isn't running. That is a completely different scenario.

 

this is interesting, how does all this work. you can't start a car without a battery and can't run one without a alt. i.ve wired complete cars and a number of items say run to battery. but you are right nothing connects derect to battery. it all connects farther down the line but i always taught it was the same thing as going right to battery. where is john when we need him?

-- Edited by frank on Tuesday 8th of March 2011 06:37:06 AM

My car runs fine with the Alt disconnected.  Well, not forever but for sometime.  Are we going to get to the chicken or the egg thing here? 

frank wrote:

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this is interesting, how does all this work. you can't start a car without a battery and can't run one without a alt. i.ve wired complete cars and a number of items say run to battery. but you are right nothing connects derect to battery. it all connects farther down the line but i always taught it was the same thing as going right to battery. where is john when we need him?

-- Edited by frank on Tuesday 8th of March 2011 06:37:06 AM

---

You can run circuits directly from the battery and to a point all seems fine. I understand what you're saying about instructions to run a power wire to "battery" but they just mean 12 volt positive power, not necessarily the battery itself. Most modern instructions could benefit from more explanation. The engineers realized some time back as amperage draw kept increasing, that the battery was a bottleneck in the flow and went to the 1 wire design. Electricity follows the path of least resistance and by providing a location between the battery and alternator, the amperage went directly to the draw. If you are familiar with a bus bar, that is essentially how the circuit works. Yes, it's all still connected but the power can flow directly to the draw and not thru the battery. Many cars now have 100+ amp alts and running that level of amperage thru the battery constantly will cause it to overheat and self destruct. Hence my initial reply to run the fans from the alt wire rather than the battery post. The wire needs to go thru the fuse holders first to protect the alt and then to the relays that control the fan by temp or manual switch.

Dashboard, good comparison question about the chicken and the egg. With a fully charged battery, once running, you can remove the alternator and the engine will run for a limited time until the battery wears down to a level of voltage that won't support spark. Conversely, when you jump a car with a dead battery from another car, once the engine starts, what keeps it running if the battery is dead ??? The alternator. You could jump start that same car with no battery and once it is running, remove the cables and drive it until it runs out of gas. Now, is the battery the chicken or the egg ? You need both initially to start the engine but not the battery once it is running. You can't have eggs without chickens and you don't get new chickens without eggs.........you need both but for different reasons. As for which came first ??? I'm just a wrenchhead, not a politician.....

 

Here is my 2 cents on this. It does not matter where you grab power from so long as the wire to that spot is adequet to handle the amp draw and not create a big voltage drop or overheat the wire and melt it. But for the wire coming from the stud on the back of the alternator you definitly want to run that either directly to the battery or to the starter main terminal.

Second is the fact that yes you can run a car without a battery but no alternator will ever keep up with a cars electrical load at idle and will need a battery to keep system voltage from dropping low.

I just think this is a funny so i had to add it.

This post is going to get interesting we must remember electrical theory is just that, theory, so it may be no one is right and no one is wrong. Quite often water or the flow of water is used by some to help others understand how electricity flows. So how’s this sound. I go to the sink and turn on the cold water, the water comes from the city’s water tower (alternator) but then I decide I want warm water, now some of the water is coming from my hot water heater (battery). It all runs into the sink and it’s all water. Ok so since we have a post dedicated to splitting hairs here’s another question. Is it a motor or is it an engine under the hood of your car?

I prefer to focus on Chris whupping up on a poor Mustang. I hope his wife doesn't catch him treating horses that way!::

don't know where this is going my car runs fine. same battery for 10 years, pick up my power down line from alt. did have question on 3 wire verse one wire why do you think the alt. builder recomended 3 wire over one wire i did tell him i planned on killing alt. why i was running 1/4 mile, even though i never have tried it. i thought it would hurt the spark. whats your thoughts on that?

OK, This is what I am doing 1) I think Mitch is on to something and I am sure this was beat to death. The alternator is a Voltage controlled current source. The battery is a "storage" of potential energy source. 2) It is probably best to use 3 wire and to have the current put into the system most central to the system to have shorter runs to distribute the current to the loads and to have the voltage sence at the point current is put into the system. Ground case of alternator to block. 3) I am going to use 6 gauge wire from alt to horn relay 6 gauge from horn relay to to 10 gauge fuse wire to starter. Next 6 gauge wire from horn reley to front of car for fans and head light relays. 4) I like the single wire because I am lazy & it will work, but I do not think it is the best way to do it. Plus everyhting else on the car is extream over kill why stop. Plus not so sure it will be best from a safety perspective. Now for the idiot light and I hope this work. Use the origianl volatage regualtor connector tie the blue and brown together and disconnet the red and white. The the #1 from alt to the jumped blue or brown. #2 is voltage sence I will run a 10 or 12 gauge to the horn relay where everything else is. I am even tempted to put my voltage gauge there, but it will be always on reading voltage not sure if that is a good idea or not. I will 86 my current gauge. Powermaster just told me to run it single wire to battery. I think they concern is poor charging wire voltage drops with is hooked right to battery you will not have a big drop

all I know is I trust Chris P. You all might be right for all I know, but at the end of the day, all my questions go through him.

from hot rod august 1998:

http://www.hotrod.com/techarticles/engine/hrdp_9808_one_wire_alternator_install/index.html

MAD Electric has always been a good source of information. I use their remote solonoid, www.madelectrical.com/catalog/st-1.shtml

When I bought my upgraded alternator to support dual electric fans I went with Alterstart, http://storesense1.mysuperpageshosting.com/HS13162/Detail.bok?no=745

The Alterstart guy says his alternator connects direct to the battery.

Mark at MAD says the alternator should NOT connect direct to the battery.

Now that I am building a new car I have to re-think this!?!