Charging Failiure

[tinryan]

Hey everyone,

I've got a M1078a0 which has a failed charging system. The truck runs and drives just fine, but the alternator is not putting out any extra voltage (it reads around 24v and 12v when running). I've gone through the whole TM troubleshooting guide and have gotten to the step of replacing either the entire alternator or the voltage regulator.

Some contextual information; when I first got the truck it did have a few weird symptoms that I though were just part of it being a military truck. First thing I noticed was the backup camera I installed would have something like scan-lines going across the screen when the truck was running, but be fine when just running off the batteries. The other symptom was the dash lights would flicker at idle or idling at a stop, but be fine once the truck was moving. Also, the turn signal flashing unit would never flash at regular intervals when running but is fine now that there's only battery power. The reason I didn't worry about it too much was because the alternator was charging everything just fine at the time. But now all of a sudden the alternator just stopped charging.

Currently the truck has a 76761-N1506-1 alternator with a 76761-N3030 voltage regulator.

As of now I'm going to be removing the starter to take to a shop for repairs since it's been acting up (starter gear is spinning before it's all the way out causing it to occasionally grind), and I've been thinking of taking the alternator with it to see if they can run through it and repair any potential issues.

My question to all of you is, has anyone experienced something like this and know what part is more likely to be the issue? I certainly don't want to be throwing the parts cannon at this thing when I don't have to, and it'd honestly be kinda nice if the whole issue was the voltage regulator as that's a relatively quick and easy fix.

Any insight would be greatly appreciated!

 

[coachgeo]

what is battery voltage(s)

Clean the terminals on the Rev. Polarity Box.

 

[tinryan]

what is battery voltage(s)

Clean the terminals on the Rev. Polarity Box.

Currently all the batteries are reading around 12.5v, but I charged them since the 12v batteries were down around 11.7v.

I'm now remembering that I have already cleaned the Rev. Polarity Box and covered the contacts in a bit of dielectric grease a while back to try and fix the flickering issue and I remember it had no effect, but the system was at least still charging at the time.

I can certainly go back and check it again when I get the chance.

 

[coachgeo]

Currently all the batteries are reading around 12.5v, but I charged them since the 12v batteries were down around 11.7v.

I'm now remembering that I have already cleaned the Rev. Polarity Box and covered the contacts in a bit of dielectric grease a while back to try and fix the flickering issue and I remember it had no effect, but the system was at least still charging at the time.

I can certainly go back and check it again when I get the chance.

well you got that pretty covered. Now guess measure the outputs at alternator and follow the path down from there at any spot you can to see if it drops anywhere?

hmm. now think about it.... how is your ground from alt. to chassis? Maybe clean that up good?

 

[tinryan]

well you got that pretty covered. Now guess measure the outputs at alternator and follow the path down from there at any spot you can to see if it drops anywhere?

hmm. now think about it.... how is your ground from alt. to chassis? Maybe clean that up good?

I've cleaned up the ground strap between the alt. and the chassis with good continuity between the two. reading directly from the lugs on the alt. I'm getting 24v and 12v. Nowhere near the expected amount.

 

[coachgeo]

Does your alternator regulator have LED's. Usually it is newer ones... but sometimes you get lucky and the regulator has LED's indicators that flash based on whats going on

 

[coachgeo]

Check to see if the excite wire is telling the alternator to set abut to do it's thing. Think its 24v. Comes from the Oil pressure switch on the engine. This has been a common issue with A0's. That wire is known to Fubar itself. A few folk have found the Oil Pressure switch to be no longer working too.

Search in here for "Excite Wire" should bring up some of the info ton this topic

 

[tinryan]

Does your alternator regulator have LED's. Usually it is newer ones... but sometimes you get lucky and the regulator has LED's indicators that flash based on whats going on

Unfortunately mine does not appear to have the LEDs since it's the older model n3030

Check to see if the excite wire is telling the alternator to set abut to do it's thing. Think its 24v. Comes from the Oil pressure switch on the engine. This has been a common issue with A0's. That wire is known to Fubar itself. A few folk have found the Oil Pressure switch to be no longer working too.

Search in here for "Excite Wire" should bring up some of the info ton this topic

Oil pressure switch is all good and the excite wire is getting 24v as expected

 

[Ronmar]

Have you gone thru the Neihoff manual troubleshooting steps? There is a procedure in there to determine if it is an alternator or regulator.

As mentioned you need 24v on the ENG terminal on the voltage regulator, thats the forward screw terminal on the reg, to turn on the alternator. That power comes from relay K11s de-energized contacts.. . When you turn on the main switch, the oil pressure sw powers K11. When the engine starts and goes above 15PSI, the oil pressure light goes out, K11 de-energizes and powers the regulator. So you need at least 21v on that ENG terminal when the Engine is running. If you dont have that power there, you can jump power from the 24v output terminal on the alt to see if it starts chargine to rated voltage, 14.1/28.2…

are you sure your batteries are OK. A bad battery could pull all the alt output and make it appear that you have a bad alt… And as always I highly recommend you drop to just 2 batteries. The 4 batt bank is grossly oversized for a 100A dual volt alt.

as for getting an auto electric shop to look at it, that may not work out. It appears that Neihoff only distributes parts to their service centers, so those are typically the only people who work on them.


here is a link to the Neihoff troubleshooting guide.

https://ceniehoff.com/Documents/Ctrl_Hyperlink/TG18_uid252021124312.pdf

 

[Skyhawk13205]

I have that same alternator, mine has a ripple of about .5v at idle. Since it is not a hard failure the niehoff manual does not have a clear troubleshooting step. Did your voltage gauge have a flutter before the alternator died?

 

[tinryan]

Have you gone thru the Neihoff manual troubleshooting steps? There is a procedure in there to determine if it is an alternator or regulator.

As mentioned you need 24v on the ENG terminal on the voltage regulator, thats the forward screw terminal on the reg, to turn on the alternator. That power comes from relay K11s de-energized contacts.. . When you turn on the main switch, the oil pressure sw powers K11. When the engine starts and goes above 15PSI, the oil pressure light goes out, K11 de-energizes and powers the regulator. So you need at least 21v on that ENG terminal when the Engine is running. If you dont have that power there, you can jump power from the 24v output terminal on the alt to see if it starts chargine to rated voltage, 14.1/28.2…

are you sure your batteries are OK. A bad battery could pull all the alt output and make it appear that you have a bad alt… And as always I highly recommend you drop to just 2 batteries. The 4 batt bank is grossly oversized for a 100A dual volt alt.

as for getting an auto electric shop to look at it, that may not work out. It appears that Neihoff only distributes parts to their service centers, so those are typically the only people who work on them.


here is a link to the Neihoff troubleshooting guide.

https://ceniehoff.com/Documents/Ctrl_Hyperlink/TG18_uid252021124312.pdf

-24v is present on the eng circuit once the engine is running, so that appears to be working correctly.

-The batteries should be fine as they are only about a year or two old, but I can certainly go get them tested for their CCAs. I'm running four of the the original size 6TL batteries.

-Fair point, and the shop mentioned that that as well, but promised they can at least try what they can. I was totally unaware of this Neihoff guide, so massive thank you for bringing it to my attention. I will have to run through their steps once I get a chance and see what it determines.

I have that same alternator, mine has a ripple of about .5v at idle. Since it is not a hard failure the niehoff manual does not have a clear troubleshooting step. Did your voltage gauge have a flutter before the alternator died?

I did not notice any kind of a flutter on the voltage gauge before it stopped working. The analogue gauge never showed anything and the few times I was measuring it with the multi-meter I never noticed anything drastic.

 

[tinryan]

Okay, so I've followed the manufacturer troubleshooting guide that Ronmar linked (super thanks by the way) and according to those tests, the voltage regulator is bad.

I know Midwest Military Equipment has the N3030 voltage regulator for sale, but does anyone know of another place that might have one for sale or if someone on this site might have one available? Or is there another model of these voltage regulators that would be compatible with this alternator?

 

[coachgeo]

Okay, so I've followed the manufacturer troubleshooting guide that Ronmar linked (super thanks by the way) and according to those tests, the voltage regulator is bad.

I know Midwest Military Equipment has the N3030 voltage regulator for sale, but does anyone know of another place that might have one for sale or if someone on this site might have one available? Or is there another model of these voltage regulators that would be compatible with this alternator?

IMHO if your in a boat to have to fork out huge sums of money... Dump the Neihoff and spend the money on getting a domestic commericial 24v alternator and a 24v to12v convertor to run the 12v stuff. There is some threads in here on this idea. Also Jerrit sells a mount kit... can also get kit from him where mount bracket includes place to put AC compressor for that future upgrade.

https://www.facebook.com/groups/154125488331132/user/1071491368/

 

[GeneralDisorder]

I agree - wouldn't spend a dime fixing the 100A alternator. They are undersized to begin with. If you had the 260A it's a different story.

Go to a commercial 24v and 24v to 12v voltage converter and don't look back.

Or do the conversion to the 200A HMMWV alternator if you feel you need the full enclosed water/dust proof Niehoff.

 

[tinryan]

IMHO if your in a boat to have to fork out huge sums of money... Dump the Neihoff and spend the money on getting a domestic commericial 24v alternator and a 24v to12v convertor to run the 12v stuff. There is some threads in here on this idea. Also Jerrit sells a mount kit... can also get kit from him where mount bracket includes place to put AC compressor for that future upgrade.

https://www.facebook.com/groups/154125488331132/user/1071491368/

For some reason that link is not working for me, but then again I don't have a FB account so that may be why.

Are there any 24v alternators that you all would recommend or at least how many amps should I be looking for in one? I'd like to keep the mounting modifications as minimal as possible since I have limited fabrication resources.

I see other posts mention the Victron Orion IP20 70A converter and I'm liking that idea. If anyone had a guide or suggestions for wiring in a system like this I'd really appreciate it as I'm not 100% familiar with these systems and really don't want to fry anything or cause a fire.

 

[coachgeo]

For some reason that link is not working for me, but then again I don't have a FB account so that may be why.

Are there any 24v alternators that you all would recommend or at least how many amps should I be looking for in one? I'd like to keep the mounting modifications as minimal as possible since I have limited fabrication resources.

I see other posts mention the Victron Orion IP20 70A converter and I'm liking that idea. If anyone had a guide or suggestions for wiring in a system like this I'd really appreciate it as I'm not 100% familiar with these systems and really don't want to fry anything or cause a fire.

minimum Alternator with 200amp output at 24v if your heavy battery usage like a camper, that gets battery charging for Start/drive and house banks. Or off road w/heavy electric winching. Otherwise shrink start/drive to two batts and 100amp 24v will get-er-done

 

[Ronmar]

The killer on the dual volt alternator output capacity is that half of its amp capacity is delivered at 12V, so with 12v loaded to capacity, overall alt output is cut by 1/3 over that of a straight 100A@24V alt(1930W vs 2800W).

For a straight 24V alt, 100A is probably plenty, even for 4 6T batteries as long as they are standard wet cells. 240AH worth of wet cell is looking for 60A from the alt, worst case. That leaves 40A@24V, which = 80A when converted to 12V, which is way more then the truck needs… So probably 75% load on the alt worst case. i was going to look for a 100A neihoff with a bad reg to experiment turning it into a straight 100A using a reg off of a commercial 24v alt To drive it. That way people like you with a bad reg could simply buy a converter and shift to straight 24V with the installed alt chassis for less than the cost of a new regulator…

Since 240AH of service battery typically serves pretty much no purpose on a 6-7 liter diesel truck, a more appropriately sized battery bank(~100AH), a 100A@24V or smaller alt aught to last, well… forever… with a 100-120AH battery, a 50-75A@24V alt would work just fine And be very cost effective As 75A is a very common size.

For 4 AGMs 100A would be just slightly undersized As they are looking for 108A from the alt… For 4 AGMs, a 150A alt would be plenty., but again 240AH is way oversized for the truck, so downsizing is completely appropriate and also very cost effective…

Now if you want to supplement a house battery supply on a habitat, you could downsize the service battery to an appropriate size and the excess from the 100A will go a long way to boosting a house battery While on the road…

You start to close in on 200A@24v alternators and you are going to start to approach the dual volt Neihoff prices… Around 100A or less is way more common and way more affordable.

if/when my Neihoff alt craps I will probably replace it with a Delco 28, 33 or 34 Or something along that line. Commonly available, easy access to parts and any auto electric/alt shop should be able to work on it if I cant

The Victron 70A 24-12 converter would be my choice(and nearly was). It has a remote control input so you can shut it off with a remote switch. It does need to be in the cab as it is not particularly weatherproof But there is room for it under the dash on the A0 and A1. The A1R is pretty crowded down there so you would need to find another location…

I did this conversion using a vanner equalizer/converter because I got an unbeatable deal on it. Did a utube video on it on my channel(user rronmar) That will give you an idea whats involved, although I did a lot of other changes to simplify the power system that are not strictly necessary typically, but were in my case as I modified the structure for our habitat build. The converter also provides polarity protection, so the polarity box becomes unnecessary once you use the converter. A waterproof unit like a vanner or bussman could be installed where the polarity box is, fairly easilly…

 

[CONJIN]

The killer on the dual volt alternator output capacity is that half of its amp capacity is delivered at 12V, so with 12v loaded to capacity, overall alt output is cut by 1/3 over that of a straight 100A@24V alt(1930W vs 2800W).

For a straight 24V alt, 100A is probably plenty, even for 4 6T batteries as long as they are standard wet cells. 240AH worth of wet cell is looking for 60A from the alt, worst case. That leaves 40A@24V, which = 80A when converted to 12V, which is way more then the truck needs… So probably 75% load on the alt worst case. i was going to look for a 100A neihoff with a bad reg to experiment turning it into a straight 100A using a reg off of a commercial 24v alt To drive it. That way people like you with a bad reg could simply buy a converter and shift to straight 24V with the installed alt chassis for less than the cost of a new regulator…

Since 240AH of service battery typically serves pretty much no purpose on a 6-7 liter diesel truck, a more appropriately sized battery bank(~100AH), a 100A@24V or smaller alt aught to last, well… forever… with a 100-120AH battery, a 50-75A@24V alt would work just fine And be very cost effective As 75A is a very common size.

For 4 AGMs 100A would be just slightly undersized As they are looking for 108A from the alt… For 4 AGMs, a 150A alt would be plenty., but again 240AH is way oversized for the truck, so downsizing is completely appropriate and also very cost effective…

Now if you want to supplement a house battery supply on a habitat, you could downsize the service battery to an appropriate size and the excess from the 100A will go a long way to boosting a house battery While on the road…

You start to close in on 200A@24v alternators and you are going to start to approach the dual volt Neihoff prices… Around 100A or less is way more common and way more affordable.

if/when my Neihoff alt craps I will probably replace it with a Delco 28, 33 or 34 Or something along that line. Commonly available, easy access to parts and any auto electric/alt shop should be able to work on it if I cant

The Victron 70A 24-12 converter would be my choice(and nearly was). It has a remote control input so you can shut it off with a remote switch. It does need to be in the cab as it is not particularly weatherproof But there is room for it under the dash on the A0 and A1. The A1R is pretty crowded down there so you would need to find another location…

I did this conversion using a vanner equalizer/converter because I got an unbeatable deal on it. Did a utube video on it on my channel(user rronmar) That will give you an idea whats involved, although I did a lot of other changes to simplify the power system that are not strictly necessary typically, but were in my case as I modified the structure for our habitat build. The converter also provides polarity protection, so the polarity box becomes unnecessary once you use the converter. A waterproof unit like a vanner or bussman could be installed where the polarity box is, fairly easilly…

I just did the conversion to a Delco 33I alternator, 24v and 100amps. I already had a Bussman 100A converter/equalizer that I was using to equalize the two batteries (as soon as they were connected in series, the one battery would drain the other down). Rather than an ignition switch, I installed a keyed switch that turns on batteries remotely through an electronic disconnect and I also installed one between the two batteries. Now when the key is off, no electricity can flow anywhere, including between the two batteries. So the equalizer has been unnecessary since I did that, but when my regulator stopped working on my last trip, I decided to look for alternatives and since I already had the converter, it worked out great.
The new alternator has much narrower lugs, so I machined a slot for the rear lug in the original mount and machined a bushing to fit between the fwd lug and mount, to give it the correct back spacing.
I was also able to get rid of the PPD since the Bussmann unit already has it inside. I can happily report that it's working great!

 

[Ronmar]

Nice, yep, the equalizer is only needed if you are drawing 12 out of the series wired 24v battery bank. if you use the vanner or bussman as a converter(or any other 24-12 converter for that matter), the batteries only ever see 24v in or out so will naturally find their own state of balance And act like one large battery.

install looks great!

 

[CONJIN]

Nice, yep, the equalizer is only needed if you are drawing 12 out of the series wired 24v battery bank. if you use the vanner or bussman as a converter(or any other 24-12 converter for that matter), the batteries only ever see 24v in or out so will naturally find their own state of balance And act like one large battery.

install looks great!

Thanks, I'm really happy with it and thanks for the idea!