200 AMP Dual Voltage Alternator Help

Spoke to Niehoff tech today, not much help.
I have a 6.5 with the Niehoff 200 amp dual 14/28 v alternator on my M998. I've decided to do the 4L80e upgrade and want to use the 14v side of my alt to charge my rear battery so I don't over draw from it.


Problem:
I followed Augi's write up on how to do this exactly (or at lease I think I did it right). I figured before I hook up my 8ga +14v lead from the +14v post (front of regulator with the yellow insulator at bottom of post) I'd run my engine and check just to make sure I have +14v coming out. Threw my multimeter on it and, nothing….


The IGN post is putting out +28v


The AC post is putting out +14v


Unhooked the big green connector on the drivers side of the unit (3 pins) two pins show +14v and the third shows just shy of that.
Unhooked the big green connector on the back of the regulator, left 2 pins show +28v, other 2 show nothing.

If the regulator is bad, then why does the AC post have +14v, and the IGN post have +28v, and the ALT is charging my batteries just fine, no issues there. Any help is much appreciated.

Thanks,

WAGNUM

why do you have a black wire grounding out the post on the front of the regulator? At least that is what it looks like.

You only ground the 14v stud if you are NOT hooking up the rear battery.

Correct, I have removed that ground jumper wire from the +14v post. Still no power...

You need it hooked up to the battery for it to work.

Does it not put out voltage until it sences the battery is low and needs charging?

WAGNUM said:

Does it not put out voltage until it sences the battery is low and needs charging?

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IT needs a load....

Once again, SS saves my bacon! A big thanks to the Big Dogs for helping me out. Neihoff tech support should have you guys on speed dial...

How do I test to check the +14v side is working?

Have you had good results with this setup? Are both banks of batteries getting charged enough for what they're needed for? I was thinking about just putting in 2 deep cycle 12v and installing a Blue Sea ACR with disconnect switch for all my accessories. It was my understanding that the 12V charging side reduces the 24v output because it's using part of the current on one stator. I'd hate to undercharge my starting batteries and prematurely wear them out.

I called Neihoff in the spring time trying to understand how the dual voltage regular system works and I was lucky enough to get someone on the phone that explained it well to me. Here is what I remember and this should clear up some other questions asked in this thread.
Yes the single yellow 12 volt stud on the regulator is setup to look for a battery so it only outputs voltage when connected to a battery or load. Yes if using the 12 volt stud the total amperage output stays the same but it gets divided so you would not have 200 amps available on your 24 volt side at one time the 12 volt side would take a portion of it.
I connected a 50 amp circuit breaker to that yellow stud feeding a marine fuse panel for only what I wanted connected to 12 volts mostly for a 120 volt power inverter to run my Milwaukee job site radio with built in battery battery charger and to have USB ports to charge cell phones and I plugged in the AC power inverter with a cigarette lighter style end into a female power receptacle I mounted into a large existing hole near the passenger seat it was a perfect fit and came out nice and clean. I was very happy with it. Then I added a ground side battery disconnect keyed switch and when the ground was totally disconnected this is when things got interesting. Even with the power inverter switch in the off position and the rear battery ground totally disconnected when I turned on the big switch to the run position I was hearing relays click in the glow plug controller box and for the life of me It made no sense so I called Nehioff back and they said its the voltage regular looking for a battery or load that was back feeding through the electronics in the power inverter that was in the off position so connect to that yellow stud with caution! As long as you plan on leaving the wiring and grounding alone like it came from the military I think it will be fine. I was told by a retired HMMWV tech that the 12 volt side "dual voltage" was added to run the transmission control module TCM for the 4L80e transmissions which is your goal. I cannot imagine the TCM using that much power to have much if any affect on the rear battery life and even charging but the even charging thing people speak about it something I have not really researched or know much about. I would advise to stay away from AGM batteries if not used as a daily driver I am in the off road business and these Optima Batteries are always having issues in vehicles that are not driven often. Some of the batteries in new vehicles I have personally dealt with would shock you that they don't even last a year I dealt with one of those this weekend from a 2018 2500 Diesel ram that uses 2 12 volt batteries driven daily. I have a feeling that with high 12 volt loads such as a winch or allot of lights I can see where it may effect the charging rate since 12 volt accessories tend to pull about twice the amperage as a 24 volt accessory and that maybe these batteries get a bad reputation because the quality of new batteries is not what it used to be.

The deal-E-O with the 200 Amp 28 /14 alternator are multi fold. Big as heck to handle added loads and hold down that side of the truck, brushless design, noiseless for radios system, less headaches, 28 volt for all things military.

With GI Joe swapping in and out batteries, it is very hard to have the two work together. Maybe when both are new, but after a while one or the other will begin to fail. When the cycle starts, trying to manage an across the bank (28 v) charging condition of the two 12 volt batteries due to many variables, (internal resistance and the magic inside start a downward trend to failure)

With the 14 volt output and when tapped to the back battery provides an equalizing charge, in a sense two separate batteries charging as one, assuring 28 V with an increase in confidants to get the damm thing started. and war fighter electronics working.

This is compounded when one taps the 14 volt point to run equipment without some way to equalize the bank.

The good part is this system provides a stable 12-14 volt, 50 Amp charging circuit for the civilian goodies to power (and the 4L80 CPU) while maintaining equalization.

It is a fine balancing act,

CAMO

I think you guys just saved me a $900 on a 200 amp alternator, $50 on an installation kit, and probably a few Glow Plug Controllers/PCBs at $500 each. I think I'll just go back to my original idea and install a charging relay to keep the starters for starting and the deep cycles for house loads. Now, I have to find the switched circuit on the key ignition to tell the ACR the key is on.

Jsmith1529 said:

I think you guys just saved me a $900 on a 200 amp alternator, $50 on an installation kit, and probably a few Glow Plug Controllers/PCBs at $500 each. I think I'll just go back to my original idea and install a charging relay to keep the starters for starting and the deep cycles for house loads. Now, I have to find the switched circuit on the key ignition to tell the ACR the key is on.

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Gracious...is that what they're charging for 200A alternators now? I got mine all of a year and a half ago and paid about $250 for it, then the seller even paid some back due to damage that occurred from improper shipping for me to replace the parts. $50 is a better deal for an install kit than what I paid, but I'll happy pay extra for that to not buy a $900 alternator.

Wire Fox said:

Gracious...is that what they're charging for 200A alternators now? I got mine all of a year and a half ago and paid about $250 for it, then the seller even paid some back due to damage that occurred from improper shipping for me to replace the parts. $50 is a better deal for an install kit than what I paid, but I'll happy pay extra for that to not buy a $900 alternator.

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This one is $1,980!

This is just a 6o amp and they want over $600.

If you have a line on another $250 200Amp alternator, even if it needs to be rebuilt, please let me know. A buddy of mine runs a shop with his dad where all they do is rebuild alternators and starters. I'd gladly pay $250 for a used one, rebuild it, and not worry about running out of juice.

After reading the thread and my own trial and error - I can confirm you WILL NOT get a voltage reading without the remote battery hooked up. I actually thought I blew the regular some how, but when it was all permanently wired I had 12.6v not running and 14v when it was. All is good!