High-amp Alternator Upgrade on E30?

[hozzziii]

If you have the alt. just bench test it using only the lamp light 12+ connected see if it works, if it doesn't try puting 12v to the DFM and see. The other connection is for the ms45 the regulator drops the 12V to 8V with pulses to establish a serial connection for the dme for diagnostic reasons.

If i were you i would give it a shot since both wires in the connector are 12V power, You aren't burning anything.

I agree it's worth a shot.
I'll try it and report back, thanks!

[hozzziii]

Welp! I talked to the guy and he showed me the diagrams.
I guess we're going for it.
I was trying to upload some pictures I took with my phone, but the site just keeps giving me errors "Path cannot be empty" I dunno.

But from what I gathered, aside from the power cable and ground, there are two other cables, so far so good.
Number 1 cable on the X6524 connection is a Green/Brown cable 0.75 mm thick, which is a fused cable by the looks of it. It has 15<30 written above it, not sure what that is. The guy said this is a switched, fused cable, which means its power.

Number 2 cable on the same connection is a 0.5 mm thick Black cable, which has S_61--1 written above it that I don't understand.
This one is a fused cable that goes first to the instrument cluster, goes to the lamp, then out and into the alternator.
This one I imagine is the bulb cable, that turns the bulb off when the alt reaches 12v.

So overall I think we're good.
I found a 155A alt without the cooling duct that looks exactly like the E46 one. Although I can't find the part number that's printed on the alt anywhere to be sure which car it is from.

I don't have access to proper bench tests at least in my own city, all I found was a guy that has an electric motor attached to a metal table with a battery and a battery gauge, so not much in terms of checking the health of the alt.
I bought the alt, when it arrives I'm gonna test it like that I suppose, then if it's good I'll have a look at the regulator and check the brushes probably, and check the bearings too.

I'll try again soon and see if I can upload the pictures from the wiring diagram.
Ooh I'll also upload some pics from the alt too.

If you have any suggestions on how I can better understand the health of the alt, let me know.

[ADEN]

The e30 battery light has only one wire to cluster if the one you are after has another way to determine the health of the charge by battery light being on or off then it will generate a charge but unfortunately the battery light may always be on.

[hozzziii]

The e30 battery light has only one wire to cluster if the one you are after has another way to determine the health of the charge by battery light being on or off then it will generate a charge but unfortunately the battery light may always be on.

Well, I'm not sure I understand why you think the battery light will always be on.
Yes the E30 has just one wire that goes through the cluster to excite the alt. It even says on the service manual that if the light burns out that alt may not charge.

It was my understanding that this wire does two things, excite the field coil, and when the alt starts to charge and reaches 12v, there won't be a voltage between the wire/bulb from the cluster and the alt. Therefore the light turns off.

Also I think later E30s had a resister that was parallel to the bulb on the cluster, in case the bulb burned out, the alt would still charge. Mine doesn't.

Now on this alt I think that these two cables, from what I understood from the diagrams that I want to upload, do these two things separately.
One excites the alt, the other from the bulb has a voltage until the alt starts to charge, after which there's no longer a voltage, and the bulb turns off.
The guy I talked to said I only need a fused and switched power for the field coil, and the same wire from my cluster to check the charge.

This is my understanding.
Where am I wrong?

[ADEN]

Well, I'm not sure I understand why you think the battery light will always be on.
Yes the E30 has just one wire that goes through the cluster to excite the alt. It even says on the service manual that if the light burns out that alt may not charge.

It was my understanding that this wire does two things, excite the field coil, and when the alt starts to charge and reaches 12v, there won't be a voltage between the wire/bulb from the cluster and the alt. Therefore the light turns off.

Also I think later E30s had a resister that was parallel to the bulb on the cluster, in case the bulb burned out, the alt would still charge. Mine doesn't.

Now on this alt I think that these two cables, from what I understood from the diagrams that I want to upload, do these two things separately.
One excites the alt, the other from the bulb has a voltage until the alt starts to charge, after which there's no longer a voltage, and the bulb turns off.
The guy I talked to said I only need a fused and switched power for the field coil, and the same wire from my cluster to check the charge.

This is my understanding.
Where am I wrong?

You are correct, e46 depends on one wire for the cluster light just like the e30, i thought that e46 cluster light needs 2 wires but i was wrong.i just found a video that confirms your theory see forward to 04:00

https://m.youtube.com/watch?v=L2pk6uTvP00L2pk6uTvP00

Good luck and i will be happy to know the results when finished.

[Gregs///M]

If I remember correctly, I upgraded the alternator in my 325is, M20b25 with that from a 540I E34. I believe I used the alternator mounting bracket from the E34 and the current output was over 100A, i think more closer to 130-140A. That was a quick and easy upgrade. This was over 15 years ago so apologies for not getting too detailed.

[hozzziii]

If I remember correctly, I upgraded the alternator in my 325is, M20b25 with that from a 540I E34. I believe I used the alternator mounting bracket from the E34 and the current output was over 100A, i think more closer to 130-140A. That was a quick and easy upgrade. This was over 15 years ago so apologies for not getting too detailed.

It's all good, thank you.

I actually bought the E46 alt for less than a $100, although instead of 150A it's 155A.
Looks exactly like the 150 kind on E46, just puts out 155A. Looking through summit's lists, this alt is actually from an E60 with an M54 engine. Again, same alt, just puts out 155.
And to my luck, the alt arrived damaged through shipping, and I'm going through the process of getting some damages.

Luckily only the connector on the voltage regulator broke, so just swapping that out, although not cheap, should make the alt good to go.

[hozzziii]

Welp. A little update.
I got a new regulator, swapped it on. Gave it 12v at the regulator on both pins, no juice.
I tested the alt casing with a light cable, the casing can ground, none of the pins on the regulator or the alt main terminal can ground
the power.
Maybe the alt is internally damaged.
Or maybe I'm not doing this right and the alt doesn't respond like this, I don't know.
Will have to investigate.

Still can't upload pictures of the wiring diagrams, bummer.
Would've loved some insight, maybe I'm reading it wrong.

[hozzziii]

Well, seems we can upload pictures again.
So this is wiring diagram that I was looking at:

So you can see that the alt has got 2 wires going to it other than the power cable.
The one in the middle is a fused power cable, that goes to the No. 1 terminal.
The one on the left is also a fused power cable that goes through the dash light, and it goes to the No. 2 terminal.


Here is a close up of the diagrams.

However, I should also note that the alt I got, was a 155A alt from an E60 525i, I know this because it's essentially the same alt for the E46, just puts out 155 amps on the E60.
On summit's website the application list for this particular alt, the kind without the cooling duct, is shared between E46 325i and E60 525i.
But these diagrams are for the E46, so maybe that's where I'm wrong.

I don't maybe that is why it's not working out for me.

But let's look at the alt itself, now that I can upload pictures.

As you can see, the alt arrived damaged and these are the No.1 and 2 terminals on the regulator.
I bought a new regulator, popped it in, gave power to these pins, nothing. Doesn't even ground the power for the dash battery light.

So, I took the regulator out of the alt and took a multimeter to it for a continuity test.
Tried pretty much all the pins I can think of.
The No. 1 and 2 terminals do not ground the power, at all.
Matter of fact, I cannot find any pairs connected other than these two:

These are the only ones that are connected: the "outer" graphite brush that goes on the rotor slip ring, and this copper C shape thing that gets connected on one of the two posts behind the alt.

This is how it looks on the alt.
The bolt on the right came with a plastic cover that you can see in a couple pictures above, I assume this means that the bolt on the left is the main power and the bolt on the right is the secondary. BTW they are parallel, both receive power from the diode.

So I tried all of these continuity tests on both regulators, both have the same connections, so maybe the old regulator isn't broken I suppose.
Maybe this alt works through a digital connection and not a dumb simple analog power source. I searched and found IBS cables for the E60, this worries me.
I'm just wrong it seems.
So I'm stuck with an alt and two regulators that I can't use apparently.
Great.

[bmwman91]

If you are trying to do a simple continuity test on the regulator, then it makes sense that nothing seems to be connected. It contains integrated circuits which are either in high impedance states when off, or will act as diodes (but you'd need a multimeter than supply more than 14V to test them). It looks to me like a fairly standard "analog" alternator & Vreg. If I am reading correctly, both of the large studs have continuity to one another and serve as outputs?

You could try connecting a cordless drill to the pulley somehow and spinning it. If the drill can hit at least 700RPM then I would expect that you would see 12-14V at the outputs. If so, then that should be some confirmation that it could work in the E30.

You will need to find some way to attach a ground strap to the body of the alternator, unless it also has a stud for that that isn't seen in the pictures. The E30 alternator mounts won't work as ground connections, if this thing was intended to work that way.

[hozzziii]

If you are trying to do a simple continuity test on the regulator, then it makes sense that nothing seems to be connected. It contains integrated circuits which are either in high impedance states when off, or will act as diodes (but you'd need a multimeter than supply more than 14V to test them). It looks to me like a fairly standard "analog" alternator & Vreg. If I am reading correctly, both of the large studs have continuity to one another and serve as outputs?

You could try connecting a cordless drill to the pulley somehow and spinning it. If the drill can hit at least 700RPM then I would expect that you would see 12-14V at the outputs. If so, then that should be some confirmation that it could work in the E30.

You will need to find some way to attach a ground strap to the body of the alternator, unless it also has a stud for that that isn't seen in the pictures. The E30 alternator mounts won't work as ground connections, if this thing was intended to work that way.

I do have a multimeter, I put it in impedance mode and set it to beep when there is continuity. Only that one brush and that C shape thing.
I mean I am using it in impedance mode, so even if it was high impedance, it would at least show something?

Yes the big studs are parallel, both are outputs. I asked the tech guy and he said sometimes they're both used together, I don't know in which conditions, I guess maybe when one is limited by wire gauge maybe?
I dunno.

The test scenario:
I don't have access to bench tests in my city. However there is a guy that has an electric motor bolted to a metal work bench.
This work bench is connected to a test light which itself is connected to a battery negative. He also has some wires hanging below the work bench that are connected to the battery positive.
Very High-Tech, I know.
Of course your mind is blown, mine was as well.

What he does is he puts the alt on the table, first checks to see if the light is working, puts the wire to the table, and the light turns on.
He then asked me which connector is for the bulb, I tell him in the diagrams both should work but you start with 1 and then go for 2.
He puts his wire to these connectors, nothing.
He puts his wire to the alt casing, we have power.
He says the alt is bad, the casing can ground and not the terminals.
I asked him to please use the motor to spin the alt while putting power to the regulator connectors.
He obliged.
No power.

What a great day that was.

In all seriousness, it kinda makes sense to me, though I'm no expert.
The alt doesn't ground that dash light.
If it doesn't ground the power, then how does the rotor get power for the coil?

Could it be that the rotor gets power from the battery using that C shape piece that is connected to one of the brushes?
But I'm still not convinced, I could not find any continuity for the other brush. Meaning I'm not sure how the rotor will ground that power to generate the field.

Now it could be that in newer E60s, the dash light is controlled by the dme and is not directly connected to the alt.
Well in that case, what do these connectors on the regulator do then? What do I do with them?

Also yes, I know I can't use the E30 mounts for ground.
Actually 4-cylinder E30s, like mine, came with a ground strap at the back of the alt that was bolted to the engine.
I would've done the same with the new one, just with a bigger wire gauge.

So, with this information, what do you suggest?

[bmwman91]

Many active circuits are in the high mega-Ohm range when in high impedance states, so I would not expect to see much with a multimeter, at least not consistently.

I am not entirely following what you had described as far as the tests that were done. What is the deal with the test light bulb?

My assumption is that the "C" thing is the output from the voltage regulator. The brushes which engage the commutator are where the unregulated AC voltage is generated.

As far as the 2 smaller terminals on the regulator, it looks like you want 12V for #1 and ground for #2 (if I am seeing the diagrams correctly). It could be part of some sort of logic circuit to enable the regulator.

[hozzziii]

As far as the 2 smaller terminals on the regulator, it looks like you want 12V for #1 and ground for #2 (if I am seeing the diagrams correctly). It could be part of some sort of logic circuit to enable the regulator.

Wait, I don't get it.
Pin 2 is the dash light, the wire has power.
Why would you ground the wire from the dash light?
I mean let's say I ground the wire from Pin 2 to ground, but then where do I connect my own dash light? How will I know the alt is charging?

[bmwman91]

Maybe I misread the diagram...the lower left is cut off and I assumed that there would be a ground icon down there. If not, then yes perhaps you will be connecting the dash light the same way that it is in the E30. It is unknown whether the functionality is exactly the same since the light connects to the regulator on this alternator, versus a tap on the diode plate on the E30 alternator. You may need to try top access an E60 and get the multimeter on the pin #2 branch to see what voltage is present in accessory & run modes.

[hozzziii]

Maybe I misread the diagram...the lower left is cut off and I assumed that there would be a ground icon down there. If not, then yes perhaps you will be connecting the dash light the same way that it is in the E30. It is unknown whether the functionality is exactly the same since the light connects to the regulator on this alternator, versus a tap on the diode plate on the E30 alternator. You may need to try top access an E60 and get the multimeter on the pin #2 branch to see what voltage is present in accessory & run modes.

Yea no the lower left is the same wire, I just tried to fit the whole picture without backing up too much that the picture becomes unreadable.

Yea I did actually find an E60 at a dealer, it just was a late model and the alt was totally mounted differently so I thought what's the point.
I will probably either find another E60 or just buy something from an E46 or E36.

I know a guy that has E46 alt for sale, I'll ask him to put power to the regulator with a test light, and if it lights up, I'll buy it.
If it doesn't, I guess I'll just do what a lot of people have done on E30s and buy a 140amp E36 alt.
I just hate that ugly duct they got, plus I reaaaalllyy don't want to make a duct for an alternator, just really not looking forward to it.

Oh well.
I will update with what I find.
Happy Holidays!