Alternator

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Neil3478

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2 questions, if anyone can help out!
Mine is a 1973 3.0CSi, Fjord Blue, UK right hand drive, manual. The 'L' warning light is constantly on but everything seems to work fine. I have replaced the voltage regulator with a new Beru one, still everything fine but 'L' light will not go out. It dims slightly when I rev the car up. I would like to replace the alternator with a modern/upgraded one. Does anyone know a model number, or serial number or anywhere where I could get a better alternator. The only other option is to get the current one refurbished. Has anyone got any ideas? The car has only had 2 owners and has 90,000 miles so I want to sort this L light problem out.
Secondly, and just curious really, on the top of the thermostat housing is a plastic orange cover with a plug type thing attached with a brown wire going somewhere. Does anyone know what this is? Looks like you can plug something into it but don't know what!!
Many thanks for any help. Will try and upload a picture of the car today!
Finally, just been reading a post about the wooden strip across the dashboard. Lovely patina but bits are flaking off. Any idea how I can get the wooden piece off and what sort of refurbishment to give it? It seems pretty secure and I don't really want to have to dismantle the whole dashboard!
 
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as to the "L" issue, you'd better do some electric readings with an appropriate instrument, battery voltage, before and after engine is on

difference in that reading can tell more than you imagine

new alternators directlyavailable from bmw dealer, but usually they are internally regulated, so you will have tobypass your regulator

plastic orange plug, for bmw testing equipment forget about it unless you have the mentioned tester machine

as to the dash wood, probably you are not serious about taking the dash apart, so live with those flacking off bits, and consider them part of the coupe joy, ;-)
 
Stevehose said:
Lots of info if you search the forum:

http://www.e9coupe.com/forum/showthread.php?t=10961&highlight=alternator+internal

The alternator model is a Bosch AL45X and can be bought rebuilt with higher amperage (mine is 85 amps-stock is around 55).

Likely will come with the internal regulator, you can keep the stock regulator for looks and just disconnect it but keep the wire for the red light intact.
Click to expand...

In the case above, you need to keep the unused stock regulator because it's a significant part of the engine bay :-)
(Have the aluminium polished and put some new fresh correct yellow tape on)
 
I used a later alternator for an E24, takes about 20 min to replace the alternator and bypass the external regulator. Be sure you ground the case.
 
Internal regulator alternator not charging

Sorry to jump into this thread, but I have a related alternator question. I have the one-wire Bosch with internal regulator and last night it stopped charging. By the time I got home the battery was dead. When I hooked jumper cables to the battery from the other car, the alternator started charging again, and continued to produce 13.8v after I removed the jumpers. So I let it run and it soon recharged the battery. This morning the car started fine, but again no charging, voltmeter showed under 12v.

Any ideas from the group?

Thanks,
Tyler
 
Tyler said:
Sorry to jump into this thread, but I have a related alternator question. I have the one-wire Bosch with internal regulator and last night it stopped charging. By the time I got home the battery was dead. When I hooked jumper cables to the battery from the other car, the alternator started charging again, and continued to produce 13.8v after I removed the jumpers. So I let it run and it soon recharged the battery. This morning the car started fine, but again no charging, voltmeter showed under 12v.
Any ideas from the group?
Click to expand...

Ideas . . . ?

Intermittent charging? Charging, then no charging?

First reaction is a short or bad ground. Loose wires, corrosion? Unlikely, but could you have a loose or slipping drive belt? If you have an alternator that is mounted on rubber bushes, it is also unlikely but possible that the bushes are in such bad shape so as to interfere with or prevent adequate adjustment of the drive belt.

If you were using the older style externally regulated alternator, usual test is to jump the voltage regulator. You actually do have a regulator that you can replace that is incorporated within the module retaining the two carbon brushes. Like anything else electronic, it may be reliable, but I doubt it is 100% impervious to defects, external forces and forever lasting. I suppose a brush might stick, but I also suppose it/they might also be severely worn. Not particularly difficult to remove via two fasteners, but can be awkward to access with the alternator in place.

Best of luck.


For illustrative purposes:
LucasBosch5.jpg

bosch_regulator.gif


Another style (rectangular) "internal voltage regulator module."
Internally_Regulated.jpg
 
Thanks guys. I'll have a look this weekend, starting with the ground and wiring and working my way to the regulator then the unit itself.

What's weird is that I can repeat what happened. Starts up but no charge flowing. Turn off, hook up jumper cables to another car that is running, restart and charge starts flowing.
 
Bad ground connection somewhere? Have you disassembled and cleaned the battery connections, the ground straps to the chassis (both of them)? I would start with the easy stuff.

When using the jumper cables did you have the ground cable connected from battery negative to negative, or was one end connected directly to a ground on the engine itself? Wondering if there is some initial resistance threshold that is overcome when jumpering that keeps the alternator charging.
 
Tyler said:
Sorry to jump into this thread, but I have a related alternator question. I have the one-wire Bosch with internal regulator and last night it stopped charging. By the time I got home the battery was dead. When I hooked jumper cables to the battery from the other car, the alternator started charging again, and continued to produce 13.8v after I removed the jumpers. So I let it run and it soon recharged the battery. This morning the car started fine, but again no charging, voltmeter showed under 12v.

Any ideas from the group?

Thanks,
Tyler
Click to expand...

Is this the typical one-wire setup?

[FONT=&quot][FONT=Arial, Helvetica, sans-serif]1-Wire Explained[/FONT][/FONT][FONT=Arial, Helvetica, sans-serif][FONT=&quot]
[/FONT][/FONT] [FONT=Arial, Helvetica, sans-serif]A 1-wire alternator, also known as a self-exciting [FONT=&quot]alternator, [/FONT]is commonly used on custom cars & trucks, tractors and other non standard applications when simplified wiring is a factor. [FONT=&quot]As the name implies, these alternators provide only one wire connection: the BATT terminal. A heavy cable is typically run directly from the BATT terminal to the positive terminal of the battery. [/FONT][/FONT]
[FONT=Arial, Helvetica, sans-serif]1-wire alternators are essentially 3-wire setups that have been rewired internally for a simplified final installation:[/FONT]

  • [FONT=Arial, Helvetica, sans-serif][FONT=&quot][FONT=Arial, Helvetica, sans-serif]No Remote Voltage Sense Input:
    [/FONT]    [/FONT]    [/FONT][FONT=Arial, Helvetica, sans-serif]The regulator's sense line is still used, but instead of connecting to a remote location in your car, it is simply routed directly to the output feed of the regulator. This connection may be inside the alternator where it would be completely hidden from view, or the sense line may actually have an external terminal attached to the output feed stud on the back side of the alternator (see photo above).[/FONT]
[FONT=Arial, Helvetica, sans-serif]A common complaint among custom street rod owners using the 1-wire setup is that their headlights are dim, even with a huge 100-amp alternator wired directly to the battery. This is due to the lack of remote voltage sensing at the power distribution point.[/FONT]
​
  • [FONT=Arial, Helvetica, sans-serif][FONT=&quot][FONT=Arial, Helvetica, sans-serif]No Field Excite/Warning Light Indicator Input: [/FONT][/FONT]
    The ignition warning light indicator function is omitted with a 1-wire alternator, so your idiot light will not be operational with this setup.
    [/FONT] [FONT=Arial, Helvetica, sans-serif]F[FONT=&quot]or the 1-wire, self-exciting design, the field windings are not [/FONT]energized via the ignition switch; instead, a special circuit is built into the internal voltage regulator that senses the rotation of the alternator’s rotor. The rotor must turn at sufficient speed to trip the circuit which excites the field windings and starts the charging process. This “cut-in” speed is affected by several things and is typically higher with certain high amperage alternators. Prior to reaching the cut-in speed, the charging system is not activated and the battery will be discharging. However, once the cut-in circuit is tripped, the alternator will charge at all speeds, even very low ones, until the alternator’s rotor comes to a complete stop. At that point, the circuit will shut off and wait for the process to be repeated. [/FONT]
    [FONT=Arial, Helvetica, sans-serif]Typically, after starting the engine, the engine must be revved above 1200-2000 RPM to turn-on the 1-wire alternator.[/FONT]
[FONT=Arial, Helvetica, sans-serif]
The advantage of a 1-wire system over the 3-wire system is that the installation is simplified and provides for a very clean installation. All that is required is a heavy gauge cable running between the output feed stud on the rear of the alternator and the battery.
[/FONT][FONT=Arial, Helvetica, sans-serif][/FONT][FONT=Arial, Helvetica, sans-serif]
[/FONT]
[FONT=Arial, Helvetica, sans-serif]http://bob_skelly.home.comcast.net/~bob_skelly/alternator_conversion/wiring_alternator1.html
[/FONT]
 
I found that revving the car to 3k got the alt to start charging on its own, which was suggested by 61porsche and jmackro in this earlier alternator post:

http://www.e9coupe.com/forum/showthread.php?t=12680&highlight=charging

As Sven suggested, by jumping the car, this might have accomplished the same thing as revving to 3k. What happened this time was that I started the car at night in very cold weather, immediately turned on the headlights, and let it sit to warm up. Since I hadn't given it a bit of rev to "excite" the alt, the battery soon was drained.

I will hook up the dash light to see if that resolves the issue. I also cleaned and tested the grounds for preventative maintenance.

Thank you all for the advice,
 
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