alternator charging problem

Started by mini420, August 12, 2010, 02:58:29 PM

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OK so I have another problem.

Turns out my alternator is not charging my battery. I had the alternator tested and it is good out of the car but dosnt charge in the car.
So its not receiving the the signal to charge. 

From the manual it looks like the signal comes from the instrument panel through a regulator to the alternator. Problem is I no longer have the stock instrument cluster or the regulator.

So what can I do.

1980 Morris Mini 1293 Morspeed engine


I'm horrible with electrics, but wonder if you can add the regulator in line with the system?


I thought alternators had an internal regulator?  There was a separate voltage regulator for the old generators.  I think I also recall several discussion threads on Mini Mania indicating the ignition light in the dash was integral to the charging system.  If the light burned out, it would keep the system from charging the battery.  I want to say those threads were in reference to alternator based systems.  If your ignition light is out or missing, that may be the problem.


yeah no your right its not a regulator. it runs into the dashboard. the dashboard has a volt stabilizer.
im not sure if that does anything.

ive heard hooking a light up to it once already. not sure if that was going to work.... i could try it

i connected the volt meter to make sure i had the right wire. at 2k rpms it kicked on the alternator
just grounding the wire didnt work... of course i just held the wire to metal. i was in a rush

any thoughts?
1980 Morris Mini 1293 Morspeed engine


Just grounding puts no resistance on the controlling circuit in the alternator.  A slight load is required to trigger it, thus the light.  At least that is my understanding from the other threads.


well using a light did not work. i used a simple 12v light that was already hooked up to a wire.
that didnt work. not sure if the volt would need to be more...

i tripped the alternator with the volt meter again then tried the light and it lit up so it was grounded properly.

i dont think the light by itself is providing enough resistance... any ideas to get more load?
1980 Morris Mini 1293 Morspeed engine


i connected a toggle switch to see if that had more resistance load whatever and it worked

i tried it with the toggle in the ON position and it it was good. putting out 13.4 steady volts.
i then tried it with the toggle OFF and it still worked. putting out 13.4 volts

i went for a small ride around the area and the volts stayed up. got home and batt read 13.4v

so its working. i dont mind having a toggle tucked away so i guess im good

thanks for the tips
1980 Morris Mini 1293 Morspeed engine



Glad you got something worked out.  I don't know enough about the circuit myself to say what is usually there that was missing, but at least your solution works.   4.gif   If you let us know some details about what the car is (year, equipment, etc.), I can try to see if I have what should be the right wiring diagram in one of my manuals.  I can then try consulting one of the hardware engineers at work and figure out what is usually in the circuit if you want.  Then you would be able to hook up a properly working light if desired.

The usual function is the light comes on when the charging system is not putting out voltage (or insufficient voltage).  Such as when you turn the ignition on without starting the car or the alternator is malfunctioning.  If you have a voltage gauge, you may not need the light circuit to know when the alternator is failing as long as your switch arrangement is in place to allow it to try to function.

Michael Playle


Dan- Yeah it was a pain in my @**. The funny thing is I have probably been riding around with no alternator for a while since I ride only so often and only during the day and in good weather.  But its good now

Mike- its a 1980 Morris.  The engine is a Morspeed 1293.  My dash is custom(if u wanna call my work custom hahaha) aluminum dash with autometer guages. It had a three cluster set up before I replaced it. 

i followed the simple Haynes diagram to a brown n yellow wire that would have connected to the dash. i still have the stock harness in the car. That is the wire the volt meter was connected to when I signaled the alternator to start and now have a toggle switch hooked up to.  A simple lightbulb wouldnt signal it.

Prior to reaching 2k RPMS the wire reads .8 volts on the 200v setting on my meter. then it jumps and holds at aprox 13.5 ish

Not sure if thats enough extra info. I would like to have something more proper i there if you ahve ideas I would appreciate it.

1980 Morris Mini 1293 Morspeed engine


Give me a few days to dig out my manuals and see what they show.  I suspect it is in the circuit board/panel on the back of the original instrument cluster where the load factor gets incorporated on the way to the light in the gauges.


Yeah thats pretty much what I figured as it shouls only go to the light. It is in the main harness to the cluster.

I wouldnt have thought about the toggle if you didnt mention resistance or load earlier.
1980 Morris Mini 1293 Morspeed engine


I am a complete technological slug when it comes to electrical. I can follow a diagram and hook things up but figuring out what it is if something is wrong is beyond me. So I read this thread with great interest.

A long time ago I tried to change to an alternator. I meticulously jumpered wires as described in the many articles on the subject. But as I recall, when I hooked things up, the red light wouldn't go out. So I though I had something wrong. I just switched back to the generator and still have the alternator on the shelf. I never did any diagnostics at the time since I wasn't sure where to measure what voltages.  So maybe I should go back and try again.


All of what seem to be the appropriate wiring diagrams have a voltage regulator/stabilizer involved.  The wire from the Alternator comes up to the light in the dash.  From the light, the other wire goes to/through a voltage stabilizer then on to the ignition switch.  Brown/yellow wire from alternator to bulb, white wire from bulb to 'B' terminal of voltage stabilizer and on to the ignition switch.

That tends to make me think the extra load is in the voltage stabilizer.