TheSamba.com :: View topic - Alternator Questions

Sat Aug 23, 2008 2:24 pm

I am doing a conversion from a 12V generator system to an alternator. The alternator that I'm trying to use is different from two other ones I have. This other unit has a Bosch ID tag and #043903023A. It has three connections on the top labeled "D" (left side), "DF" (right side) and "D+" bottom. Then there's the larger "B+ connection for the battery.

This came off a late model bug. Can anyone help me identify its year/application, as well as any guidance around its wiring? None of my workshop manuals have the wiring for this particular alternator. :roll:

A generator has connections for "D+", "DF" and the ground. This alternator is labled differently... :?:

Thanks!

Sat Aug 23, 2008 3:30 pm

thats a 74-75 alternator that needs an external regulator

B+ goes to the battery obviously
D+ and DF go to the matching terminals on the regulator
and D- goes to a ground on the regulator body
this is how my 3 74 bugs have been that had that setup stock

u need the regulator for that style of alt
its the 30amp 2 prong type u need from memory

Sun Aug 24, 2008 9:49 am

Buggin_74 wrote: thats a 74-75 alternator that needs an external regulator

B+ goes to the battery obviously
D+ and DF go to the matching terminals on the regulator
and D- goes to a ground on the regulator body
this is how my 3 74 bugs have been that had that setup stock

u need the regulator for that style of alt
its the 30amp 2 prong type u need from memory

Thanks for the great information! :D So if this particular alternator has an external regulator, I'm wondering what the advantage is to changing away from my current Generator w/regulator set-up....

Assuming that I continue on towards swapping the generator out for the alternator, I need a different regulator, correct? (different than the regulator that's currently supporting the generator system that I have) :?:

Do you have more detail on which one I need? A part number or something??? Or is it simply a regulator for a 74-75 VW Beetle?

Thanks again for your help!
8)

Sun Aug 24, 2008 10:02 am

wardvwracer wrote: Buggin_74 wrote: thats a 74-75 alternator that needs an external regulator

B+ goes to the battery obviously
D+ and DF go to the matching terminals on the regulator
and D- goes to a ground on the regulator body
this is how my 3 74 bugs have been that had that setup stock

^^^^you need the regulator for that style of alt
its the 30amp 2 prong type u need from memory

Thanks for the great information! :D So if this particular alternator has an external regulator, I'm wondering what the advantage is to changing away from my current Generator w/regulator set-up....

Assuming that I continue on towards swapping the generator out for the alternator, I need a different regulator, correct? (different than the regulator that's currently supporting the generator system that I have) :?:

Do you have more detail on which one I need? A part number or something??? Or is it simply a regulator for a 74-75 VW Beetle?

Thanks again for your help!
8)

Yes the 3 prong alternator uses a different regulator than the generator system.

There are "used" ones in the classifieds for 15-20 bucks but you can never know if they are good so it's a crap shoot.

http://www.thesamba.com/vw/classifieds/detail.php?id=649139

NEW or NOS ones pop up but are * in relative terms... pricey.

Especially if you do not know if that alternator you have is a working unit. I would take it to a COMPETENT auto electric rebuilder/shop and have it tested ( not just a local auto parts chain if you know what I mean) before I spent a dime on a regulator for it and bothered to install it. Those 3 prong were either a Bosch unit or a Motorola ( yours is Bosch AL- 82) and were primarily used on 73 from mid year through 74. 75 went to the internal regulator style.

Sun Aug 24, 2008 12:52 pm

If this is the one, and you need it, I can send it to you, and if it works send me $25.

jim

Sun Aug 24, 2008 3:16 pm

You need to know if your alt is Bosch or Motorola.

From a previous post>

"Is yours a Bosch or Motorola brand alternator? They each have their own regulator, and they as they have become more and more scarce the prices skyrocketed. It's often just as easy just to buy a whole new internally regulated alternator instead. You can't hardly even find stuff for the Motorola ones anymore. Below is a picture of what a Motorola alternator looks like, note the Motorola "M" stamp on it, and the 043903023 part number, which goes with a 043903803 regulator. The Bosch alternator was AL78X (043903023A) and used a 30049 (043903803A) regulator. "

jim

Sun Aug 24, 2008 4:18 pm

If it's the one he posted the pic of in his original post it's got a Bosch sticker on it. :wink:

Sun Aug 24, 2008 5:36 pm

Here's the two different externally regulated alternators.

Bosch, on my convertible:

Motorola, on my sedan:

Sun Aug 24, 2008 6:40 pm

mnussbau wrote:
Bosch, on my convertible:

That's it! Mine is also a Bosch unit. Both appear to have the same part number (043903023A), and it matches mine. Any chance you can snap a pic of the regulator? Also, if possible, please see if there's a part number on it.

Also, is there a wiring harness that connects the alternator with the regulator? The regulator's pictured above and in the ad appear to have "male" connectors, just like the alternator. So I'm guessing there is a wiring loom that has both ends "female". :?:

Sun Aug 24, 2008 6:50 pm

wardvwracer wrote: mnussbau wrote:
Bosch, on my convertible:

That's it! Mine is also a Bosch unit. Both appear to have the same part number (043903023A), and it matches mine. Any chance you can snap a pic of the regulator? Also, if possible, please see if there's a part number on it.

Also, is there a wiring harness that connects the alternator with the regulator? The regulator's pictured above and in the ad appear to have "male" connectors, just like the alternator. So I'm guessing there is a wiring loom that has both ends "female". :?:

Yes the reason for this is the regulator plugged into the wiring harness under the rear seat of the vehicle... not directly into the top of the alt.

Sun Aug 24, 2008 7:30 pm

Here's two slightly different shots. (Hey, I really need to clean up under there!)

edit: if you really want I can pull the cover off the regulator tomorrow and look for the P/N.

Sun Aug 24, 2008 7:46 pm

Thanks! These photos really help me out. :wink:

Sun Aug 24, 2008 8:32 pm

Dang, might be easier/cheaper to just get an internally regulated alternator and be done with it.

Very informative thread. I'll be sure to stay away from the externally regulated alts. If I do come across one, I'll put it up here for some of you folks that like to keep things factory.

Mon Aug 25, 2008 3:31 pm

Mark33563 wrote: Dang, might be easier/cheaper to just get an internally regulated alternator and be done with it.

Very informative thread. I'll be sure to stay away from the externally regulated alts. If I do come across one, I'll put it up here for some of you folks that like to keep things factory.

Actually, a number of people have written me to tell me that the alternators with the external regulator are better. The point people are making is that when the alternator with the internal regulator wears out you toss the whole unit. This can mean a fair amount of work to R&R and then the only thing available is the Chinese copy alternators. Whereas the ones with the external regulator don't wear out as often and if there's a problem its usually the regulator. Simply replace the regulator and you're back in business. :wink:

Finally, it was also suggested that the external regulator may actually be more efficient and manage the voltage better. Dunno.... :?

Agree, this thread has been very informative and helpful. Thanks!

Mon Aug 25, 2008 8:37 pm

wardvwracer wrote: Actually, a number of people have written me to tell me that the alternators with the external regulator are better. The point people are making is that when the alternator with the internal regulator wears out you toss the whole unit. This can mean a fair amount of work to R&R and then the only thing available is the Chinese copy alternators. Whereas the ones with the external regulator don't wear out as often and if there's a problem its usually the regulator. Simply replace the regulator and you're back in business. :wink:

Finally, it was also suggested that the external regulator may actually be more efficient and manage the voltage better. Dunno.... :?

Agree, this thread has been very informative and helpful. Thanks!

I have no idea which one is more efficient or better. I have only purchase one new generator and one new alternator. I guess I have been lucky over the past 25+/- years of running the junk I have been dealt. The last alternator I purchased was back in 1992, I think. It was to convert my '70 ghia vert from a generator. Ran it for years with no trouble.

The internal regulators can be replaced if they go bad, it just cost a little more. But I think you are right, most people, including me, would just junk it and get another. Right now my DD is running a generator. If it goes bad, I have about 3 other generators and an alternator standing by. The only reason I do not convert it to run the alternator is that I do not want to screw with something that is working just fine right now. In fact, I took the alternator off the engine before I installed into my DD.

I do not put alot of demands on my charging system. No amp, no 21" subs, etc. Just a plain jane simple AM/FM/CD/MP3 player with two front speakers. I plan to add a couple of speakers in the rear when I get some extra scratch. No fog lights, no air trumper setup....

Fri Feb 11, 2011 12:51 pm

what regulater do i need for a motorola alt. and how do i wire the car for the gen. to alt swap...i dont know how to post pics of my generator regulator so i have no idea about where the small red wire is.
the only thin red wire i have goes to the ignition switch...i think :?