The alternator is in....the questions begin

So far I bought a 6 gauge wire and ends and a 4 guage and ends, the seller at the auto and tractor service place I went to (NOT Pep Boys) advised a thicker ground wire, so I am using 6 for hot and 4 for ground, and will be grounding to the neg terminal on batt. Guy also advised that I ground batt to frame, body and block. Is 6 TOO much for a 63 amp alternator?

I will go out to the Jeep and look around to see about the AMP light wiring etc. although I still am not sure which wire comes from the AMP liht, I can prob figure that out.

Do I NEED a volt meter??? I am still confused on this line of discussion.

Also the wire from the number 2 connector gore right ot the posittive terminal? seems odd that two wires run from ALT to BATT directly, but I will set that up.

 

Matt, you don't "need" a voltmeter but it's a fairly good instrument to have.

If you have a voltmeter on your dash you can tell at a glance what your battery voltage is doing with and without the motor running.

Say after you get this all set up, some day in the future, and you hop into your jeep and turn the key to "on" and the voltmeter jumps over to between 12.5 and 13 volts. You know that your battery is having a good day. Then you go ahead and start the motor and the volt meter doesn't go up - this means that you need to rev up the motor a little to wake up the alternator. So you rev up your motor and the volt meter jumps up to above 14 volts. Now you know that your alternator is charging and everything is right with the world.

This is why you want a volt meter, but you don't have to have one.

 

Got it, OK so I can do it later. not needed for the job at hand.

Cool thanks!

 

The gauge is inversely proportional to the size (i.e. 6 gauge wire is bigger than 4 gauge wire). The larger the wire, the less the loss, in this case bigger is fine.

You don't need a voltmeter, but it's a good thing to have for diagnostic purposes. I alway like to have one so you know what is going on.

The number 2 wire is the voltage sense. You can put it on the battery terminal or any other electrical junction you want to allow the alternator to monitor and adjust the voltage to.

An excellent article on the advantages of the 3-wire alternator is shown here:

http://www.madelectrical.com/electricaltech/onewire-threewire.shtml

 

I am not an expert on this and am providing this information from memory. The documents I emailed to you should cover everything in detail. Trust them over whatever I tell you. Anyways, here is my understanding.

The 2 posts/connectors that eventually run to the battery serve 2 different functions. The BATT post is for the power output. It has to handle a lot of amperes. Hence, the fat wire. The #2 terminal is for voltage sensing needed for the internal regulator. To optimize the function of the alternator, the voltage sensing wire should not go directly to the battery, but instead to a junction where there is likely to be a voltage drop, such as a fuse box, bus bar or starter solenoid. This way, when there are draws on power, the alternator knows it immediately and puts out more power.

On my jeep, the starter solenoid is the main junction. My fuse box is not powered directly from the battery but instead taps into the postive post on the solenoid. (IIRC, this post also has the large wire coming from the battery.) The sensing wire from the #2 terminal is connected to the BATT post on the alternator on top of the large wire. The large wire from the BAT post is connected to the positive post on the solenoid. My theory is that since the fuse box draws its power from the same spot, any drop in voltage is sensed and the alternator output increases. My jeep sits for months at a time and I run a lot of lights. So far, everthing has worked perfectly. I'll email to you another pdf diagram from a Jeep website that is pretty much the way mine is set up.

You don't need a voltmeter. But it will immediately let you know if something is wrong. It is nice to know that you are running off the battery before you get too far from civilization. In my opinion, if you install the alternator as a 1-wire, it is absolutely critical to have a voltmeter. Everything will work without it but you would have no idea whether your alternator ever "turned on." I have an aversion to buying batteries or walking home. Been there, done that.bunny with a pancake

 

Sorry for the information overload, but here is a pretty good site. http://mightymo.org/Proj_OneWire.html A lot of information and pictures.

I am begining to wonder whether my sensing wire (from the #2 terminal) should have ran all the way back to the main junction at the starter solenoid instead of being connected to the BATT post on the alternator. It is connected to the output wire which runs back to the solenoid, so it , indiectly, goes back to voltage drop area. Does anyone know whether it makes a difference?

 

It depends on how big the wire between the alternator and the battery is. If you have the sense wire connected to the output of the alternator, the alternator's regulation circuitry will hold that point at approx 14.1 volts. If the wire between the battery and alternator is small or has some resistance, there may be a voltage drop (you could measure this with your voltmeter), so it may read 14.1 at the alternator, but maybe 13.8 at the battery (or something else). If the wire between the two is sufficiently large, the voltage drop between the two could be negligible.

 

My external regulator started acting up a few days ago so I'm installing an 85 amp CS 130 tomorrow. I had installed one in another truck I had several years ago and ran it thru the stock wiring with no problems. The stock wiring had a 10 gauge wire for the output to battery.
The CS 130 is a really great alternator upgrade when you're running electric fans like I was doing in the other truck. It really puts out at lower rpms .

 

That's what I meant to say, didn't mean to add to the confusion.

 

Thanks for the information Eric. Are you saying that if I have a large enough output wire, that I should not experience a material voltage drop at the junction? Even if I am drawing500 watts?

Unfortunately, I don’t fully understand electrical theories so I know just enough to confuse myself. Problem is, the more I think about this, the more I think my jeep is not set up in the best possible manner. I should leave well enough alone since even the way my alternator is wired, it works great. I run 3 sets of lights (2 headlamps; 2 - 100 watt off road lights; 2 - 50 watt utility lights) and occasionally 1Mil spotlight without any dimming, even at low rpms. But this may be more a product of the CS130 instead of the wiring configuration. However, theoretically, it seems that I should run the sensing wire all the way to the junction on the starter solenoid, instead of running it 6” to the BATT post on the alternator. It seems that voltage should never drop at the BATT post. So if I want to sense a voltage drop, I would need to run the #2 wire to the remote location where a drop is likely to occur. In my case, the starter solenoid junction. Does anyone have an opinion on this???:?

CJjunk, I agree with you. I have been very pleased with the CS130. I swapped in a CS130 in the place of a 10SI. However, I had to make a new long arm bracket. The 10 SI bracket would not work with the CS130. Documents I have read said to make certain you have at least 35 ohms in the Idiot light circuit. I think I put about 70 ohms in mine.

 

If the wire gauge is small enough (wire diameter is large). Here's a chart/calculator showing the wire gauge and the voltage drop:

http://www.gadgetjq.com/wiring_size_guide.htm

Using the calculator, if you have a 130 amp alternator, worst case, you could generate 130 amps. According to the chart, if you plug in some numbers (assuming 2 feet of 6 gauge wire), the voltage drop is 0.2 volts, so if the alternator was putting out 14.1 at the back of the alternator (because you put the voltage sense on the alternator output), the battery would see 14.1-0.2 = 13.9 volts, probably not enough difference to worry about.

If you are drawing 500 watts (P=I*v), that's I=P/V=500/12=41.6 amps. At 41.6 amps, the voltage drop would be 0.1 volts, so the battery would see 14.1-0.1=14 volts, based on this, you probably don't need to move the voltage sense wire (unless I'm missing something here).

That said and done, I'd still put the #2 wire at the location that you want regulated to 14.1 volts, for the reasons described in:

http://www.madelectrical.com/electricaltech/remotevoltagesensing.shtml

 

Just to confuse matters a bit more (keepin' it real?), the heavy wire from the alternator to the starter solenoid should be fused, generally with a fusible link at the end nearest the battery. This will introduce a slight voltage drop as well. Still not likely to be significant, though.

 

Wish my wireless reached all the way to the storage "tent" where I keep "Barney" but it is like 9 degrees outside anyway..so not happening soon.

MEANWHILE I have been having a waking nightmare.....

I drove "Barney" with the newly installed alternator spinning for about a mile from the place where we mounted it back to my place, with the main post wire attached to batt and ground wire to ground only, and wires prob not thick enough for the application....

Did I harm my new Alternator before I even got it working?

 

Thanks for the information Eric. Next time I see my jeep, if the sensing wire does not run all the way to the junction at the starter solenoid, then I am going to change it. I am also going to check the size of the output wire. If I am reading it correctly, the gatgettq.com website says I should have at least a 5 ga. wire to handle the full 105 amp output of the CS130. I am not really worried about it at the moment because I doubt I ever draw more than 70 amps. But you never know, in the future I might want to add radiator fans or a toaster over.

Matt, please disregard my earlier statement about running the sensing wire from the #2 terminal to the BATT post. Instead run it all the way to the main junction. Also please notice that the pdf’s I sent you are inconsistent on this point. The diagram contained on document “chargecircuit—lamp wiring.pdf” is correct. The diagram in “Jeep alternator-solenoid wiring.pdf” should have shown the sensing wire going all the way to the junction at the starter solenoid.

CO64CJ5, Do you think we should put a fuse in the output wire if the wire is oversized (larger than what the engineers say is needed to carry the maximum output of the alternator). In my research, I have found inconsistent statements on the need for a fuse in the output wire. I am guessing that those which do not mention a fuse feel that if the wire is oversized, then a fuse is not needed. ....I don't know. ....Probably is safer to have a fuse.

 

I doubt it. The problem with undersize wires is that they melt if too many amps go through them. It doesn't take too many amps to run the engine. If you were not running all your accessories, then you should not have overburden the wiring. Bottom line: if your wires did not melt, you should be OK.

D**mn! It's cold here in Texas too -- in the 60's.

 

I can confuse myself about this, as well. I could even make an argument that there should be a fusible link at each end of this wire. You need to evaluate the risks.

What you're fusing against is not an overload like putting too many lights on a circuit, but rather a dead short or a failure inside the alternator. In this case, it's not the alternator's output you're concerned about, but how much can the battery pump through that wire into a dead short -- it's easily several hundred amps, which is certainly enough to make a 6-gauge wire incandesce.

If there's not much risk of this wire being abraded against the engine or frame, or melted against an exhaust header, you're probably pretty safe without fusing it. If I ever get around to doing this on mine, I'll probably at least add some protection like split loom, and route the wire carefully. But the fuse is such cheap insurance compared to what can happen.

 

I drove "Barney" with the newly installed alternator spinning for about a mile from the place where we mounted it back to my place, with the main post wire attached to batt and ground wire to ground only, and wires prob not thick enough for the application....

No, it won't hurt the alternator. Now if you left the "Batt" wire off and drove it, then you would have burned up the rectifier.

One more note to those who are arguing about 1-wire alternators vs 3-wires.
The best way is to use a 1-wire alternator but go ahead and hook it up with 3 wires. This makes it start charging at a lower rpm and also gives you a little insurance. If the #1 & #2 wires fail, the alternator will keep on charging.

 

I like CO64CJ5's logic. I am going to add a fuse to the output wire.

 

That's definitely the safest thing to do. It's not cheap, but with some creative wiring, something like one of these might work:

http://www.solar-electric.com/f125ampcltfu.html