Can I use a Niehoff 400amp regulator on a 200amp alternator?

I think the 200amp regulator on my '92 m998 is shot. Sometimes I get charge, sometimes, I don't, voltage floats around, it cuts in and out, etc. Troubleshooting indicates that alternator is probably OK. I've cleaned up all the wires I can find. Looking at the auction sites and elsewhere, right now there is a glut of 400amp regulators (n3211) for cheap. My current regulator is the 200amp n3106 version. Is it OK to use the larger regulator on a smaller alternator, or is that a no no?

If connections are the same, it should work no problem. IF connections are same. 400 A alternator should have similar number of coils/wires/connections. Being more robust it will regulate/filter the output of the smaller alternator just fine.

I’m not an IEEE-rated engineer but I did stay at a really nice hotel one night and I’m a ham radio guy with some electronic/electric tinkering history.

Let us know. There was a guy on fakebook’s HMMWV page selling the 200A units a couple weeks ago for about $300 delivered. Look around.

And this IS the place for such inquiries, thanks for bringing it up.

I have seen a M1113 use a 400. I would think if you can mount it, it will provide the 24 and 12 that you need.

NV555 said:

I have seen a M1113 use a 400. I would think if you can mount it, it will provide the 24 and 12 that you need.

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It’s not the ALTERNATOR he’s asking about, but the REGULATOR. Good question.

NormB,

My EE education is so rusty now it has sunk, and fish are swimming through it in its new role as an artificial reef, but that was my gut as well: if the regulator fits, and the wires line up, then it should stand a good chance of working. The price for the 400 amp regulator is a quarter that of the 28v single voltage 200amp regulator, so I feel it's worth a shot. I want to go through the alternator test procedure one more time now that I'm not so peeved. I had just finished replacing a tie rod end and was going to go off roading tomorrow when I noticed the truck wasn't charging. Before I jump on the new regulator I should re-confirm that the alternator hasn't died, especially the rectifier.

Thanks!

Are you expecting 400 amps or just want to know if it will work at all?

Action said:

Are you expecting 400 amps or just want to know if it will work at all?

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Not expecting 400amps. Just want to know if it will work.

kestrelnh said:

Not expecting 400amps. Just want to know if it will work.

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Did the test per pp 6 in one of the Niehoff tech guides that more or less matches my alternator. The only thing that I really couldn't check well was the field coil resistance, since I'd need to know what that is specifically for the alternator model I have, but it wasn't crazy town (it read 2 ohms).

The testing all points to a bad regulator. I've ordered one the 400amp regulators that really looks like it is physically identical to the 200 amp ones as far as the overall size and plug are concerned. If it doesn't work, I'll be out $70, and pony up for the correct $300-$400 one that is meant for the 200 amp alternators.

I suppose my biggest concern is the AC phase wire going into the regulator. If that's different between alternators in a way that makes the regulators not be cross compatible, then I'm probably out of luck.

Niehoff tech assistance has been helpful to me in the past. Try reaching out to them. Very few members on this site are going to have 400 amp units installed.

the pin-outs on the N3211 and the N3106 are the same so Pin A is Field -, Pin B is Phase, Pin C Ground(B-),Pin D is B+(battery positive), the Filed coil on most C. E. Niehoff are about the same value, they are all brushless so its just a coil of wire you are testing. so you field coil looks ok based on the value you show, remember to subtract meter lead resistance when measuring OHMs. now as to if it will or will not work, since the pin out is the same and technically the "signal" should be similar as they are based on the same basic design they yes it should work. now there maybe some reason it doesn't in the software inside the Regulator but I can't be sure. also double check the IGN(energize) terminal power on the regulator and make sure that it is a good voltage there. Also double check your batteries each individually to make sure there isn't an issue with them affecting the system.

juanprado said:

Niehoff tech assistance has been helpful to me in the past. Try reaching out to them. Very few members on this site are going to have 400 amp units installed.

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I reached out to Niehoff and they said there was a pretty good chance it should work between those two particular regulators, and if it didn't, very little chance it should hurt anything. SO... waiting on parts

kestrelnh said:

I reached out to Niehoff and they said there was a pretty good chance it should work between those two particular regulators, and if it didn't, very little chance it should hurt anything. SO... waiting on parts

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I just put the new regulator in and it seems to be working fine. I had to drill another mounting hole on the regulator casing, but just matched where Niehoff had made the extra hole on the old regulator. It's charging fine at all RPMs. The only weird thing is while the AC post is putting out 14VAC, the control unit doesn't seem to recognize it, so my running-engine starter solenoid disconnect isn't working. I'll have to look at that further.

curious what came of this; still working okay? i had a nice 200a alt show up with a cracked regulator case and just curious if i can buy a $70 regulator instead of a $400 one.

another member pointed me toward my current 100a niehoff and sure enough, its the same reg as the 200a. but if i can get the 200a working without pirating the one off my 100a, thats be awesome!

Waters said:

curious what came of this; still working okay? i had a nice 200a alt show up with a cracked regulator case and just curious if i can buy a $70 regulator instead of a $400 one.

another member pointed me toward my current 100a niehoff and sure enough, its the same reg as the 200a. but if i can get the 200a working without pirating the one off my 100a, thats be awesome!

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It was working fine earlier in the summer, but I just noticed today I seem to be getting slow swings up to 32 volts or so. I'm going to check all grounds, but I may be in it for a new $300 regulator.

I think I'm in for a new regulator, and if I'm very unlucky, a new alternator.

kestrelnh said:

I think I'm in for a new regulator, and if I'm very unlucky, a new alternator.

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So, my conclusion at the end of this is I'm sourcing a new-to-me alternator/regulator combo. I don't know if my alternator is killing the regulator, but I burnt through one n3106, and then had a n3211 that worked four a couple of months. The original n3106 stopped charging, and now the n3211 is over charging. No load to speak of on my rig. Just time to get a nice dual voltage setup to keep those batteries balanced

So, I got my new n3106 regulator from the big auction site, and it's a bit weird. There is what looks like a small, exposed potentiometer in the potting on the bottom, and there's no name plate. It works fine. I heard southern automotive was building these now. Anyone ever seen an adjustment embedded into the potting before?

Hey kestrelnh, if it doesn’t have a name plate it isn’t a N3106 Niehoff part it is a clone the southern automotive parts aren’t Niehoff they are clones so it’s a bit of a gamble if it’ll work with the original unit it may very well work but it’s not an original just a clone of unknown origins

kestrelnh said:

So, I got my new n3106 regulator from the big auction site, and it's a bit weird. There is what looks like a small, exposed potentiometer in the potting on the bottom, and there's no name plate. It works fine. I heard southern automotive was building these now. Anyone ever seen an adjustment embedded into the potting before?

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Could you post pictures of this design?