adding dual alternator setup
Lead Driver
Joined: Dec 2006
Posts: 7,093
Likes: 147
From: San Diego, CA
I will say that if one starts to die then the house of cards crumbles (to paraphrase beef ****
) and you're in for double the cost for replacements. Like batteries, you should replace them in pairs.
Banned
Joined: Dec 2018
Posts: 3,541
Likes: 458
There is a video by Toomanytoys (he posts in the 6.0 section) that somewhat touches on the glowplugs and higher output alternators. The 6.0 motor has a GPCM that shuts the plugs off if the voltage exceeds I guess 14.4 or 14.5, which you can see that happening in the video when he is testing the Leece-Neville alternator, which apparently runs the voltage a tad too high for the GPCM liking. 7.3 engines just had a dumb relay with no override but the CA emissions trucks I think has the GPCM just like the 6.0 does, prompting the question as to whether it could be swapped onto the non-GPCM equipped trucks for added protection. On cold day I usually leave the key on for about 45-50 seconds anyway before cranking the motor but the glow plugs only stay on for 120 seconds maximum (if it is very very cold) so that is not very long.
Butt-Head
Joined: Apr 2004
Posts: 9,453
Likes: 2,936
From: Reed Point, MT
There IS voltage mapping for the glow plug control on a 7.3L. I see it on my 1995 all the time as the high idle when cold will cause the alternator to raise the voltage over the threshold and the glow plugs turn off immediately. If I drop the idle back down (provided the lights are on or blower motor is running), the voltage goes down and the glow plugs will turn back on for the remainder of the 120-second cycle. For the last few years though, I just limit the time to 30 seconds on the glow plugs regardless of how cold it is so I don't worry about it anyway.
The 1999-2003 PCMs have the same mapping but I have yet to really try it out (no reason it wouldn't work the same) since the high idle is automatic and delayed until after the glow plugs have turned off (again, 30 seconds).
The 1999-2003 PCMs have the same mapping but I have yet to really try it out (no reason it wouldn't work the same) since the high idle is automatic and delayed until after the glow plugs have turned off (again, 30 seconds).
Cargo Master
Joined: Jul 2011
Posts: 2,675
Likes: 979
From: Walpole, MA
Very glad I stumbled across this thread.....
I have been catching up on some "deferred maintenance" on my father's truck (rust on the cab corners, exhaust manifold cracks, starter, batteries, rear brakes etc) and noticed that since it started to get cold in the mornings (few days with temps in the lower twenties so not arctic circle by any means) the truck throwing out more white smoke than expected at start up. My father dropped a 240 amp mechman alternator on the truck (has a 8.5' western plow on it in the winter) but never upgraded any of the battery cables of the truck. This summer I put additional 1/0 lines from the alternator to the batteries (including cross over) and an additional 1/0 ground from the block to the frame. After doing that the alternator is throwing out 14.2-14.5 volts at nearly all times, so it might be tripping the voltage mapping causing the the GP's to cut out? Maybe? Time for me to break out the multimeter and alligator clips.
Sorry for the ramble just never thought of this. I assumed one or more of the plugs were going out.
I have been catching up on some "deferred maintenance" on my father's truck (rust on the cab corners, exhaust manifold cracks, starter, batteries, rear brakes etc) and noticed that since it started to get cold in the mornings (few days with temps in the lower twenties so not arctic circle by any means) the truck throwing out more white smoke than expected at start up. My father dropped a 240 amp mechman alternator on the truck (has a 8.5' western plow on it in the winter) but never upgraded any of the battery cables of the truck. This summer I put additional 1/0 lines from the alternator to the batteries (including cross over) and an additional 1/0 ground from the block to the frame. After doing that the alternator is throwing out 14.2-14.5 volts at nearly all times, so it might be tripping the voltage mapping causing the the GP's to cut out? Maybe? Time for me to break out the multimeter and alligator clips.
Sorry for the ramble just never thought of this. I assumed one or more of the plugs were going out.
Banned
Joined: Dec 2018
Posts: 3,541
Likes: 458
Very glad I stumbled across this thread.....
I have been catching up on some "deferred maintenance" on my father's truck (rust on the cab corners, exhaust manifold cracks, starter, batteries, rear brakes etc) and noticed that since it started to get cold in the mornings (few days with temps in the lower twenties so not arctic circle by any means) the truck throwing out more white smoke than expected at start up. My father dropped a 240 amp mechman alternator on the truck (has a 8.5' western plow on it in the winter) but never upgraded any of the battery cables of the truck. This summer I put additional 1/0 lines from the alternator to the batteries (including cross over) and an additional 1/0 ground from the block to the frame. After doing that the alternator is throwing out 14.2-14.5 volts at nearly all times, so it might be tripping the voltage mapping causing the the GP's to cut out? Maybe? Time for me to break out the multimeter and alligator clips.
Sorry for the ramble just never thought of this. I assumed one or more of the plugs were going out.
I have been catching up on some "deferred maintenance" on my father's truck (rust on the cab corners, exhaust manifold cracks, starter, batteries, rear brakes etc) and noticed that since it started to get cold in the mornings (few days with temps in the lower twenties so not arctic circle by any means) the truck throwing out more white smoke than expected at start up. My father dropped a 240 amp mechman alternator on the truck (has a 8.5' western plow on it in the winter) but never upgraded any of the battery cables of the truck. This summer I put additional 1/0 lines from the alternator to the batteries (including cross over) and an additional 1/0 ground from the block to the frame. After doing that the alternator is throwing out 14.2-14.5 volts at nearly all times, so it might be tripping the voltage mapping causing the the GP's to cut out? Maybe? Time for me to break out the multimeter and alligator clips.
Sorry for the ramble just never thought of this. I assumed one or more of the plugs were going out.
I have that one and like it.
4th Gear
Joined: Dec 2022
Posts: 4
Likes: 0
I will more than likely go with a HO single as it is more cost effective. Not to mention the ease of maintenance/replacing.
I DID however answer my own question in regards to the PCM programming. The answer is...I DO NOT believe the programming matters. I dissected the secondary alt. harness on the 2001 truck. I traced the wires of this harness from the secondary alt. to the plug that sits between the fender and battery. There are three wires that make up the secondary harness. One large 8ga. wire that runs from the back of the secondary alt. up the starter relay on the inner fender. The other two smaller wires come off the two wire pigtail on the back of the secondary alt. and run up to the main pigtail/harness between the inner fender and battery. I then unplugged the secondary harness from the main harness (truck side) and found the two pins on the main harness that correspond to the two smaller wires that run to the back of the secondary alt.
I took several voltage readings off these two pins with the KOEO and found that with the GPR activated the voltage to the secondary alternator was limited to 10volts. Once the GPR kicked off the voltage rose to the appropriate amount. This just verified that the secondary does indeed reduce voltage (just like the main alternator) when the GPR is activated. Once I was satisfied with the info. I gathered from the 2001 I stepped over to the 2000 (truck in question).
All I had to do with the 2000 was test the same two pins on the main (truck side) harness. Since there is no secondary harness on the 2000 the main harness just terminates into a dummy plug on the inside of the fender. Long story short I got the same readings on the 2000 as I did on the 2001. Almost seems like the secondary alt. just piggy backs off the main alt. signals (?) That leads me to believe that PCM reflashing is maybe not needed.
Other than making my own harness (not hard at all) I think it would work. Anyways, it intrigued me...I get bored easy LOL!!!
I DID however answer my own question in regards to the PCM programming. The answer is...I DO NOT believe the programming matters. I dissected the secondary alt. harness on the 2001 truck. I traced the wires of this harness from the secondary alt. to the plug that sits between the fender and battery. There are three wires that make up the secondary harness. One large 8ga. wire that runs from the back of the secondary alt. up the starter relay on the inner fender. The other two smaller wires come off the two wire pigtail on the back of the secondary alt. and run up to the main pigtail/harness between the inner fender and battery. I then unplugged the secondary harness from the main harness (truck side) and found the two pins on the main harness that correspond to the two smaller wires that run to the back of the secondary alt.
I took several voltage readings off these two pins with the KOEO and found that with the GPR activated the voltage to the secondary alternator was limited to 10volts. Once the GPR kicked off the voltage rose to the appropriate amount. This just verified that the secondary does indeed reduce voltage (just like the main alternator) when the GPR is activated. Once I was satisfied with the info. I gathered from the 2001 I stepped over to the 2000 (truck in question).
All I had to do with the 2000 was test the same two pins on the main (truck side) harness. Since there is no secondary harness on the 2000 the main harness just terminates into a dummy plug on the inside of the fender. Long story short I got the same readings on the 2000 as I did on the 2001. Almost seems like the secondary alt. just piggy backs off the main alt. signals (?) That leads me to believe that PCM reflashing is maybe not needed.
Other than making my own harness (not hard at all) I think it would work. Anyways, it intrigued me...I get bored easy LOL!!!
Thanks!
Butt-Head
Joined: Apr 2004
Posts: 9,453
Likes: 2,936
From: Reed Point, MT
Hello! I'm about to start my single to dual alternator conversion on my 2001 Ford Excursion 7.3L Powerstroke. You mentioned the second alternator control plug is a dummy plug and sits between the fender and battery. Was this wrapped up in electrical tape? I'm about to go fishing for the plug this afternoon and not entirely sure what I'm looking for.
Thanks!
Thanks!
Some vehicles were built with the DA harness and not equipped with the DA. Some were not built with the DA harness and therefore won't have a connector on the inner fender.
Thread Starter
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Fleet Mechanic
Joined: Jun 2015
Posts: 1,635
Likes: 564
I ended up abandoning this idea and went with a large single alternator. Much easier to replace if you have too.
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Banned
Joined: Dec 2018
Posts: 3,541
Likes: 458
A momentary or "dead man" switch is really all that is needed to put a bigger alternator on the top position. I decided not to mess with it at this point because I don't really need the extra amperage from the bigger alternator, however I bet the batteries, glow plugs, and relay would last a lot longer with the glow plug switch, and the batteries would charge faster with a Leece Neville.
2nd Gear
Joined: Apr 2024
Posts: 2
Likes: 0
I looked into dual alts at one point and it seemed like way more headache than it's worth. The single 110 alternator has been fine for how many years on your truck? Get that or the Bosch 6.0 140a and call it good. The way the second alternator works, it's not really a backup anyway. It's an odd configuration that only works sometimes. If your main alt fails, as I understand, you are still ****ed.
Tuned
Joined: Apr 2004
Posts: 433
Likes: 74
From: Aroostook County, Maine
Further to the independent excitation, that could be as simple as adding a switched circuit to your new/secondary batt system - much like adding a fog light or something. I imagine such a system that you are contemplating can be "started up" after the cranking sequence is completed, or 2 hours into your journey. In other words, at will any time the motor is running. The only detail of that separate circuit would be to make sure it shuts itself off when the engine shuts off (in case you forget to do so) and doesn't automatically energize the next time you turn the key, putting additional belt load on the engine when starting normally, which in turn puts more load on the starter. Further, all the more reason to be clever on the start/stop of this added system is so you don't introduce some funky parasitic draw. The main point is the secondary batteries will always need enough charge to create the necessary field current for the secondary alternator when you wish to engage it.
2nd Gear
Joined: Apr 2024
Posts: 2
Likes: 0
Spitballing here.... If you could fashion a way to excite the 2nd alt independent of the PCM, while similarly keeping the output completely independent of the existing system, the only thing that needs to be redone is whatever is involved in mounting the added alt.
Further to the independent excitation, that could be as simple as adding a switched circuit to your new/secondary batt system - much like adding a fog light or something. I imagine such a system that you are contemplating can be "started up" after the cranking sequence is completed, or 2 hours into your journey. In other words, at will any time the motor is running. The only detail of that separate circuit would be to make sure it shuts itself off when the engine shuts off (in case you forget to do so) and doesn't automatically energize the next time you turn the key, putting additional belt load on the engine when starting normally, which in turn puts more load on the starter. Further, all the more reason to be clever on the start/stop of this added system is so you don't introduce some funky parasitic draw. The main point is the secondary batteries will always need enough charge to create the necessary field current for the secondary alternator when you wish to engage it.
Further to the independent excitation, that could be as simple as adding a switched circuit to your new/secondary batt system - much like adding a fog light or something. I imagine such a system that you are contemplating can be "started up" after the cranking sequence is completed, or 2 hours into your journey. In other words, at will any time the motor is running. The only detail of that separate circuit would be to make sure it shuts itself off when the engine shuts off (in case you forget to do so) and doesn't automatically energize the next time you turn the key, putting additional belt load on the engine when starting normally, which in turn puts more load on the starter. Further, all the more reason to be clever on the start/stop of this added system is so you don't introduce some funky parasitic draw. The main point is the secondary batteries will always need enough charge to create the necessary field current for the secondary alternator when you wish to engage it.
https://arcomarine.com/products/arco...ator-regulator
Tuned
Joined: Apr 2004
Posts: 433
Likes: 74
From: Aroostook County, Maine
so i have a device calles an ARCO zeus alternator regulator. I think this would do what you are describing?
https://arcomarine.com/products/arco...ator-regulator
https://arcomarine.com/products/arco...ator-regulator
