Alternator 28 Volts 60 Ampere

[Steffen777]

Hello everyone,
my name is Steffen and I live in Germany. I hope I have posted this in the right place. If not, I apologize.
I've had a problem since Saturday with my HMMWV M998.

I noticed that the positive cable on the alternator was loose. I noticed this because there was a slight smell of burnt plastic.
I thought I would clean the contact, polish the metal and tighten the cable, and the problem would be solved.
Unfortunately, that wasn't the case.
After that, my “Wait before Start” light stayed on for about 25-30 seconds and my charge indicator was in the yellow range for 25-30 seconds.
After the 25-30 seconds time, the light goes out and the charge indicator turns “green.”
Previously, it always took 5 seconds for the light to go out. The charge indicator was always in the green range.
I then measured the voltage of the batteries. Both were 12.8 volts.
I then measured the output of the alternator. Result: 13.8 volts!

Has anyone ever had this problem? Can anyone tell me how to measure the alternator, or does anyone have instructions?
It is a Sielmann S.A. Hellas - MSN 2920-00-9092483 (P/N 1092986
I have searched through all the technical manuals I have, but haven't found anything. I think I have also searched through everything on the intranet. Instructions on how to completely check/measure the alternator would be great.
I just want to rule out the possibility that a capacitor, rectifier, or the winding is broken.
And I really hope that it's not the “protective control box.”
Maybe it's “just” the regulator? I don't want to replace parts based on suspicion alone.

That's why I thought I'd write here in the forum.

I would be very grateful for any help.

 

[NDT]

This stud shown in the picture should always have +24 volts on it. The little wire is the excite wire and it will have +24 volts with the ignition on. Check for issues with the Cannon plug going into the Protective box.

 

[Mogman]

If you are seeing 13.8V at the alt output then there is an issue between the alt and the batteries it should be darn close to the battery voltage.
IE 12.8X2= 25.6V, this is the min (within reason) that you see at the alt.
There is a relay in your start box that controls the connection between the alt and the batteries (no voltage at the alt with the run switch off)
This relay is one of the common failure points in the start box, that relay also excites the alt and powers things like the W wipers and the heater fan, so check them for proper operation.

 

[Steffen777]

Thank you very much for your answers and quick help. I will check it out in the next few days. If it is due to the relay in the start box, can this relay be purchased separately? Is there an online store where it can be ordered?

 

[Mogman]

Thank you very much for your answers and quick help. I will check it out in the next few days. If it is due to the relay in the start box, can this relay be purchased separately? Is there an online store where it can be ordered?

Yes it can be replaced, there is not an "official" replacement, searching for the part number on the old relay is one way.
Here is what they look like, try to get a brand name and rated as continuous duty.

Solenoid For 24144 24V 200 Continuous Amps Cole Hersee BULK24144 Pollak 52-339 | eBay

Solenoid 24144 For 24V 200 Continuous Amps Cole Hersee BULK24144.

www.ebay.com

 

[Steffen777]

Thank you very much, Mogman, for the link to eBay.
Unfortunately, the seller does not ship to Germany. I really hope to find a seller who delivers to Germany.

 

[Mogman]

Thank you very much, Mogman, for the link to eBay.
Unfortunately, the seller does not ship to Germany. I really hope to find a seller who delivers to Germany.

That was more of just a reference, it should not be a big problem finding that type of solenoid (contactor) in Germany

 

[Mogman]

If that is indeed the problem, always confirm the actual failure, do not just start replacing parts, this often leads to additional problems making correcting the original issue much harder.

 

[Milcommoguy]

There are three wire making connections to the 60 amp units plus a ground (4).

Ground - strap to a bolt or ?? mechanical to engine ?? wire # 3B
High current output= 5A Larger 8 gauge
Sense (control to turn on = 568 Smaller pig-tail off of 5A wire
AC tap (signal to control box) = 2A Smaller wire with ring terminal

Wire number are the little tags at end of wire.

You will not have (should not) a battery voltage on the 5A and the 568 wire with the switch in STOP
You will have (should have) 24 Volts with switch in the RUN position.
The AC tap wire 2A is a signal to the controller (BOX) letting the box know engine is running.
Engine running a charge voltage in the mid green area of dash voltmeter. About 28.5 Volts.

These alternators have brushes that wear and a regulator that can fail. Like any other components. 60 amp set-up have been noted to fail / headache time. Remove, inspect, test, replace parts or whole as needed. $$$ OUCH.

60 amp truck have a contactor connecting the output to battery in the RUN position in the BOX.

Not meeting the above tests... time to dig-in to the alternator or wallet.

Test, check and wrench, CAMO

 

[Milcommoguy]

Yes it can be replaced,

Not knowing the manufacturer or model and the various revisions... it may not be the one displayed and maybe a stack of chineeeze relays.

Not all parts are the part. Read that on a fortune cookie, CAMO

 

[Mogman]

Thank you very much, Mogman, for the link to eBay.
Unfortunately, the seller does not ship to Germany. I really hope to find a seller who delivers to Germany.

Post a picture of the "start " box, it can and is refered to as an EESS (if it is the newer style) and PCB, (protection control box)
The ID info should be visible by looking under the dash far left

 

[Steffen777]

View attachment IMG_1767.jpegThis is my PCB

 

[Mogman]

View attachment 954708This is my PCB

That is a pretty old box, it is also riveted together, it probably would be wise to up grade that box and temp sensor to a smart start box, or if you are electrically inclined to rebuild the box into a manual glow plug box

 

[Steffen777]

Okay, is there a manual for converting the box into a manual glow plug box?

 

[NDT]

MMM, Prestolite box. The rest of us can dream of a start box that lasts 40 years before giving trouble.

 

[Mogman]

View attachment 954708This is my PCB

Actually I was wrong on one of my earlier statements, the W wiper is powered by a different circuit so they may operate normally even if that relay is bad.
Yes there is instructions on converting the box but I don't have it at the moment, surly someone will post it.

 

[Steffen777]

Instructions on how to convert the box would be very helpful. Hopefully someone can provide me with these. That would be really nice.

 

[Coug]

I believe these are the threads with the relevant information

How to bypass PCB? I am aware some HMMWV owners have done it. TOBASH

I'm not trying to speak sacrilege here, and I don't want to precipitate a war of words. :shock: How might I build a manual control box? My 24Volt Landcruiser just uses a glow wire to show glow plugs are ready, and then she just starts right up with the twist of a key. Civilian 6.2 Diesel...

www.steelsoldiers.com

https://www.steelsoldiers.com/threa...some-hmmwv-owners-have-done-it-tobash.182560/

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