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Discussion Starter #1
So I am putting a Delco 22si hp 150 amp alternator on my truck. I am finding two different wiring diagrams and I'm not sure which one to use. The first just has the ground wire and the Batt wire. The second uses those two wires plus two other wires at the top. Two blades labeled 1 and 2. 1 is for a sense wire and 2 is for a excite wire. So do I need these two wires or no?
 

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Is there a shorting link between terminals 1 & 2? The link is usually at the base of the metal terminals where they come out of the regulator. If the link is intact then you can connect it as a 1-wire. If the link has been cut then you will need to jumper term 1 to term 2 for it to work in a 1-wire implementation or do a 3-wire installation. If there is no sign of there ever being a shorting strip then the regulator doesn't support 1-wire operation and you must do a 3-wire.

IMHO, 3-wire installation is far superior to 1-wire.
 

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The 22si you have was probably designed for multiple applications. The terminals you need are "BAT" which is the hot output and GRD which is the ground. Do not connect BAT it to the battery. It goes to where your accessories draw their power. When accessories are drawing power it triggers the alternator to turn on. You will have a hot lead that feeds from that point to the battery. At least a 4 ga wire. On Fords the connection was usually to the starter switch on the fender. If you have a central point where all your power wires draw their power, that's where you connect it. Don't forget you need a fusible link in the hot wire coming from the alternator. Probably a 12 ga fuse for that size. GRD wire is usually 10 ga or better. Hot wire should be at least 10 ga. The other terminal on the unit include "I" which is the trigger for the charge light on the instrument panel and "R" which is for a tachometer. The "1-2" plug is more for gas applications where this is replacing a 10si or 12si. My 22si has a plastic plug in the hole where those terminals would be. It was spec'd for a Cummins diesel. Here's a link to the Delco Remy instruction sheet. Not the best, but it's something.http://www.delcoremy.com/Documents/Alternator-Instruction-Sheets/19SI,-21SI,-22SI-23SI-installation-instructions_
 

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Yep, that sounds right. It is a single wire alternator if you don't count the other 3. It senses a current draw at the hot lead and turns itself on. The 1 and 2 wires were more for vehicles with distributors and ignition coils. Also, if your 22si doesn't have the "I" terminal and you want the dash charge light to work, then those must be used. Here's a diagram showing that. You didn't say if yours has the "I" and "R" terminals.
 

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Discussion Starter #6
Yep, it has the I and the r. R will be used for tach. So are you saying I can hold a light up the the I and it will tell me when the alt is charging?
 

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The charge indicator light normally only turns on for a second until it senses the alternator is working. Not exactly sure how that works. I guess you could have one that is constantly on. Your volt meter will tell you if it's charging as well. Should read in the 14.4-14.6 volt range. If it's only reading 12 volts then it isn't charging. 12 volts output from an alternator won't charge a battery. My truck has an autolite alternator with the external regulator. When you first crank up the voltmeter is down to around 10-11 volts but when the alternator kicks in it jumps up to 14.5. After you drive a while it will settle down to around 13. That's what it take for the alternator to replenish what the batteries have lost and are losing due to accessories. About the only power drain I have is the start/stop solenoid on the IP and the heater fan. If it's raining the wipers and headlights are on. I just read in the Delco Remy manual that the 1 and 2 terminals are there if the installation is a 3 wire system. Also, the minimum charge wire size for 150 amp 12 volt is 2 ga for lengths under 13 ft. Here's a link to that Delco publication.http://www.dieselusa.com/productinfo/Delco Electrical Specs and Seletion Guide.pdf I'm not a alternator guru, but I've read a lot on the subject. The simpler you keep it the better. That is one area where you don't want to screw up. Can be ugly. That's the reason these 1 wire alternators are popular. Once they reach a certain speed they turn on. No 1-2 wires to trigger them.
 

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As easy as 1 wire alternators are to install, the 3 wire is what you really want. Sensing voltage at the distribution point instead of directly at the battery means all the current lost from battery to the distribution point is compensated for by the alternator. You are guaranteed brighter headlights running a 3 wire with the alternator sensing at the power distribution block.
 

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I just read in the Delco Remy manual that the 1 and 2 terminals are there if the installation is a 3 wire system.
This is no longer correct as those regulators have been superseded by autostart regulators, which support both types of installations. All you have to do is cut the shorting link between 1 & 2 to enable 3-wire functionality. The picture on page 1 of this instruction sheet shows the shorting bridgehttp://www.delcoremy.com/Documents/Alternator-Service-Manuals/21SI-22SI-ALL-REPLACEABLE-COMPONENTS-10539632
 

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Discussion Starter #10
This is getting more and more confusing LOL; and making me wonder if I chose the wrong alternator. Damn! 2gauge charge wire! Almost welder material.

#1. Is this thing internally regulated? I assumed so.

#2. When you say 3 wire does that mean GRND, BATT, and 1(sense) wires.

#3. am I supposed to cut something Goat?

#4. Can I tie in my Volt meter anywhere in the system or should it go to the same lug as where the charge wire connects to the starter relay?

Sorry for all the confusion guy; just trying to not catch the truck on fire!
 

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#1. Yes.
#2. 3-wire means Batt, Term 1 & Term 2. Gnd is not counted.
#3. Only if you want to config the alternator for a 3-wire installation.
#4. You can tie it anywhere you want.
 

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Jeep, not all 22si alternators have 3 wires. The one I have came off a Cummins diesel and the 1-2 terminal spot is blank, Just a plastic plug filling the hole. F100, the 2 ga wire may be overkill. I've got a wiring harness that came from a F700 with the Cummins 5.9 and the charge wire appears to be 6 ga with a 12 ga fusible link. I believe the 2 ga wire should be from the battery to the accessory distribution point. I believe that's what the wiring diagram I posted shows as well. Wiring it up 3 wire is no problem at all. Apparently the #1 and "I" terminals are redundant. I guess you use "I" if you're running 1 wire and #1 if 3 wires if you want an indicator light. In reality, 22si alternator is more or less obsolete. It has been replaced by the 24si. On the back of that unit are 5 terminals. The same 4 as the 22si plus an "S" sensor terminal which corresponds to the #2. You have two options to wire it and both will work. If the 3 wire has the potential of better performance then that's the route to follow.
'
 

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Jeep, not all 22si alternators have 3 wires. The one I have came off a Cummins diesel and the 1-2 terminal spot is blank, Just a plastic plug filling the hole. F100, the 2 ga wire may be overkill. I've got a wiring harness that came from a F700 with the Cummins 5.9 and the charge wire appears to be 6 ga with a 12 ga fusible link. I believe the 2 ga wire should be from the battery to the accessory distribution point. I believe that's what the wiring diagram I posted shows as well. Wiring it up 3 wire is no problem at all. Apparently the #1 and "I" terminals are redundant. I guess you use "I" if you're running 1 wire and #1 if 3 wires if you want an indicator light. In reality, 22si alternator is more or less obsolete. It has been replaced by the 24si. On the back of that unit are 5 terminals. The same 4 as the 22si plus an "S" sensor terminal which corresponds to the #2. You have two options to wire it and both will work. If the 3 wire has the potential of better performance then that's the route to follow.
'
Thats good to know. I would guess mine did not come from a Cummins application - I bought it rebuilt so who knows. I have BATT, GRND, S and R I believe. I haven't wired mine yet but I don't believe any of the connections are to the ignition switch so I need to figure that out. Or does it just not need it because BATT is hooked up to the hot side of the starter relay? I was going to go BATT to battery side of starter relay, ground to chassis, S to the positive feed wire at the power distribution block, and leave R empty because I don't have a tach?
 

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Jeep, I just did some investigating on my 22si. Guess what? I tugged on that black plastic plug and off it came revealing the 1-2 terminals. Never knew they were there. Just assumed that plug was there to keep the dirt out of a hole. It's always a good day when you learn something new. Now I would have multiple options as to how to connect it. Was so excited I went out and bought a pigtail to plug up to it. F100, if you need the plug you can get it at O'reilly's for $2.99. Dorman part 85841.
 

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Jeep, I just did some investigating on my 22si. Guess what? I tugged on that black plastic plug and off it came revealing the 1-2 terminals. Never knew they were there. Just assumed that plug was there to keep the dirt out of a hole. It's always a good day when you learn something new. Now I would have multiple options as to how to connect it. Was so excited I went out and bought a pigtail to plug up to it. F100, if you need the plug you can get it at O'reilly's for $2.99. Dorman part 85841.
Char - which pigtail did you get? So mine has the rubber plug as well as the I and R hook ups. Do you know if my 22SI can be installed with just the batt and ground? And could I also use the sense wire too (but not the key on wire, or the I and R)?
 

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The pigtail is Dorman #85841. Has one red wire and one white. The red is the #2 terminal which is the sensing wire. The white is the #1 which is the dash light. If you look at the diagram in Post #5 it shows the basic connection for 3 wire. The alternator will also work in a single wire configuration with just the BAT and GRD connections. I'm still curious if the #1 terminal and the "I" terminal are the same. I'll call my local alternator guys and see if they know.
 

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If you don't mind - could you ask him if it is possible to run only BATT - GROUND - SENSE? Those are 3 easy underhood connections I can make very readily and not have to hookup to the dash light.
 

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OK guys, I've got the info on wiring a Delco Remy alternator. I talked to Delco tech support and I would give them an A++ grade. They know their stuff and can explain it intelligently. So here we go. First off, we already know this alternator can be configured 1 wire or 3 wire. I asked the question if there is any difference in performance either way. The answer is no. The only possible difference is how quickly it will turn on. In a true 1 wire, the only terminals used are the BAT and GRD. Once the engine rpm reaches a certain point it turns on. My second question is where do you connect the BAT wire. Answer, the preferred location is to the battery, but to the current draw point is also fine. That cable feeds voltage info back to the alternator to trigger the voltage regulator turn on. Next question is what size wire for a 150 amp unit. Answer, up to 7 ft use 4 ga and the fusible link one size smaller (6 ga). Now for the 3 wire setup. The #1 terminal is for an indicator lamp on the dash. How that works is the lamp is wired to the ignition switch and then to the #1 terminal. When you turn on the ignition to start the engine, that light turns on because the alternator grounds it to complete the circuit and that instantly turns on the alternator. That way you don't have to wait on rpm. The alternator has an internal circuit that breaks the ground and turns off the light once the alternator is on. One caution, if the light burns out the alternator won't turn on. Keep a spare bulb. That is pretty much an industry standard for all alternators. The "I" terminal on the back serves the exact same function. If you're running 1 wire and want the instant turn on then the dash lamp hook up to the "I". That actually makes it a 2 wire connection. Now for the #2 terminal. That is a sensor wire that wires to the point of current draw. It senses low voltage and triggers the voltage regulator to charge the battery. The BAT and GRD terminals hook up as in the 1 wire configuration. So hook up is absolutely your option. I personally like the idea of the sensor wire so 3 wire seems good. Hope this clears up any questions.
 

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Discussion Starter #20 (Edited)
Awesome info! Thanks guys!

In that case I think I will go the one wire route and connect to the battery, evaluate the performance, then change it if I don't like it. I have some questions though. What rpm does it take to turn on? And if we want to do the "2 wire" set up with the use of the sense wire, does the bridge between the one and two wires in the alternator still need to be cut? Also, is a fusible link the same thing as a in-line fuse? If not, how do you wire it?
 
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