[Oneof6]

John, I am glad that your ordeal with you parasitic discharge (that sounds nasty don it?). I commend you on your tenacity and thank you for keeping us up to date on the solution process. I certainly came away learning more about this avenue of system diagnostics.
However, I am not convinced that on all 7.3 PDS vehicles that the alternator does not contribute until the glow plugs cycle off. That hypothesis is in opposition to my own test data that provided and my interpretation of the charging schematic.
I will provide that test data, again, attached. In the first DCV vs Time plot one can easily see that immediatly after the identified start with starter drain, GP's still on, voltage is being contributed as the GP's finish their time cycle and see the exact moment that the GP's time out and the full contribution of the alternator pushes the charging voltage up to the regulated limit.
I am open to believing that there may be differences in my 135 Amp alternator and your significantly larger capacity alternator effecting this curiosity.
If someone can provide data, alternate schematic or printed data from Ford I would appreciate seeing it.
John, if you you are data curious, like me, and would like to DM me your address and contact info I can mail you my data logger, the device support software is OEM free online. You could run your own DCV vs Time strart test or tests and send the data logger back when you are finished.

Jim

 

[klhansen]

@Oneof6
I'd sure like to see what voltage you get if you reenergize the GP's (jumper the big terminals on the GPR) momentarily after the alternator is "on". I'll bet that your voltage would drop back down to near full charge battery voltage. I know for a fact that GP's will draw right around 100 Amps when energized. And with a stock alternator (110A output rating), it wouldn't be able to keep up with the GP draw and send anything toward the batteries for charging.

Logic says that is correct,
1) 60 mA for the truck key off
2) 60 mA for the Alternator key off
total =120 mA

Ford says battery draw with the modules asleep (interior light off after closing the door, etc.) should be 50 mA or less. You're still more than twice that, but much improved from your initial draw. Hope it works out for you.

 

[Oneof6]

@Oneof6
I'd sure like to see what voltage you get if you reenergize the GP's (jumper the big terminals on the GPR) momentarily after the alternator is "on". I'll bet that your voltage would drop back down to near full charge battery voltage. I know for a fact that GP's will draw right around 100 Amps when energized. And with a stock alternator (110A output rating), it wouldn't be able to keep up with the GP draw and send anything toward the batteries for charging.


Ford says battery draw with the modules asleep (interior light off after closing the door, etc.) should be 50 mA or less. You're still more than twice that, but much improved from your initial draw. Hope it works out for you.

I agree, and believe that the data I provided indicates exactly that, contribution by the alternator immediatly after start, GP's still on, alternator, not stock size but close enough, not producing enough voltage and amps to keep up with the GP's still ongoing load. Then, when the GP's time out, the system voltage can go to the regulated limit of the alternator. All in the expected 2 minute cycle wait to start to GP time out.
I have no doubt that a test of my truck with engine running no GP's, alternator at 14 to 14.6 volts (where mine runs at eith min load) that jumper-forcing the GP's on would produce a drop back to near static voltage of 12 to 12.5 volts, on my 135A alternator.
On John's significantly larger than stock alternator, maybe not.

 

[John in OkieLand]

I will just have to watch it over time, today was just a Test in the driveway w/o ever putting it in gear.

I know that when the harness was backwards, the 320A alternator kicked out 14.6 volts immediately and never, ever, dropped back.

How much current? no idea, I just today received my new 1,000 amp capable Clamp On ammeter. natcherly, AFTER I quit working on the truck

that will be a test for tomorrow, to see how much the starter pulls.... it has Peak Hold, gotta figure the manual out so I can make it do that.

 

[Big Horn]

Something that might be of interest.

I came across this article today (which I remember seeing a couple years ago). Many of the same ideas that are in it were posted here recently on TDS to John but I thought the article was very well written. I also have been thinking as well about something upstream of the GPR to limit voltage as discussed in the article 👍

High Amp Alternator... meet Glow Plugs. Hope you guys can get along! - Ford Truck Enthusiasts Forums

1999 - 2003 7.3L Power Stroke Diesel - High Amp Alternator... meet Glow Plugs. Hope you guys can get along! - I started to reply to Sous's quotes below, and after realizing that I just recently wrote a similar reply to EXPACamper's thread, it seemed like this topic should have a thread of it's...

www.ford-trucks.com

 

[John in OkieLand]

Something that might be of interest.

I came across this article today (which I remember seeing a couple years ago). Many of the same ideas that are in it were posted here recently on TDS to John but I thought the article was very well written. I also have been thinking as well about something upstream of the GPR to limit voltage as discussed in the article 👍

High Amp Alternator... meet Glow Plugs. Hope you guys can get along! - Ford Truck Enthusiasts Forums

1999 - 2003 7.3L Power Stroke Diesel - High Amp Alternator... meet Glow Plugs. Hope you guys can get along! - I started to reply to Sous's quotes below, and after realizing that I just recently wrote a similar reply to EXPACamper's thread, it seemed like this topic should have a thread of it's...

www.ford-trucks.com

Reading through that, agrees with the Voltages comparisons that I made,
I have a pair of #6 copper wires from Battery to cab terminated in a Shore Power socket, intended to run my DC electric refrigerator ( SetPower states it must be supplied via a
#6 gauge power source. )

I have a DVM cigarette plugin meter there, and a DVM plugged into the Dash Power socket, so I am able to get comparisons to everything.

I also use a separate quality DVM independently to be the Reference for all the others.

I also noted the 0.2 volt difference from Battery to dash Power Socket.

What is interesting for me initially, is that when my 320A alternator control wires were reversed, it put out 14.4 to 14.6 the instant the engine started cranking over.

Having done a LOT of reading, I was counting to 30 after the WTS light goes off.
I hope, that means that the glow plugs were OFF....

What I will do for a fact, is install an LED light right off of the Glow Plug Relay, so that I know when the WTS is actually off....

Now that I have the Alternator control wires fixed correctly, I found it odd that it regulated at 12.66 immediately after starting..... I assumed that is because the block heater was on, and the outside temp was 56*F so the Alternator/PCM told the alternator to throttle back.

I will just have to watch it over time, and see what it does in different Ambient temperatures.

 

[John in OkieLand]

just did a Reread on that Article.

and the Light Bulb went ON....
i am going to install a Relay powered by the glow plug relay, and have it break the control lead to the alternator, by opening up the control lead, when the glow plugs are ON.

End of problem.

After that is done, the dash DVM meters will all register static battery voltage until the glow plug relay turns OFF.... then the Alternator will be enabled, and things will be Acey Duecy.

 

[klhansen]

Now that I have the Alternator control wires fixed correctly, I found it odd that it regulated at 12.66 immediately after starting..... I assumed that is because the block heater was on, and the outside temp was 56*F so the Alternator/PCM told the alternator to throttle back.

If you're alternator is putting out only 12.66V, it's NOT charging the batteries. The voltage of a fully charged 12V battery is 12.6V, and with the alternator at 12.66 and the batteries at the same voltage, there would be NO current flowing either direction. I think you may need to take another look at your alternator wiring, as normal charging regulation voltage is between 13.5 and 14V.
Also, as was stated earlier, (unless your alternator has some magic voltage regulation feature) there's no way the PCM (which has no connection to the charging system as I posted earlier) can cause the alternator to "throttle back". Also, the block heater has no effect on the alternator, although if plugged in long enough, may affect the Engine Oil Temperature sensor, which does report to the PCM. But again, the PCM can't control the alternator.

Your relay solution sounds like a good way to deal with any potential overvoltage concerns at the glow plugs.

 

[John in OkieLand]

I agree with what you wrote.
the 12.66 output means the alternator was not charging much, if at all.

it is 21*F out there, with ice on the ground and our driveway, and 11 mph winds....

it will be a few days before the blizzard moves out, and I can get back to the truck.