Generator problem

[t_marat]

It seems like my generator does not generate any electricity. Let me give some background.

Two days ago I noticed the battery sign would flicker with faint light right after the engine is started. It would go completely off after I press the accelerator once and never comes back. I noticed this after a 140km journey at about 140-15-kmh.
Since then I made several other trips, about 200km in total at about 140-150 kmh.

This morning I started the car as usual, had a short trip. At afternoon started the car, immediately noticed that started spinned like the battery was weak. After the next stop (after about 2kms) the car refused to start. The battery turned out to be completely empty.

My initial reaction was that the battery died of natural causes. But the memory of that flickering battery signal made me wonder if the genertor was faulty, and that all this time I was simply draining the battery. Took my friends battery, started the car. Disconnected the battery after the engine was on, and the engine would immediately shut down. I don't know if this is dangerous, but in Russian made cars if the generator is working properly, the car would continue running even after the battery is disconnected.
But all this time, the battery signal was off.

Looked thorougly in the hood. I found a cable with a connector,it has 3 contacts. It goes in the same harness as the cable for the generator. The generator is properly connected through another cable. No matter how thoroughly I looked I could not find any empty receiving connecters anywhere near that area :(

Let me also say that the past week was a very wet one. With some pools of water here and there, not deep. I avoided nearly all of them.

So what do you think guys? If my generator is faulty and not generating any electricity, why did not I get any battery warnings?

[bill g]

You would travel only a few kilometres at most with alternator not charging.
Flickering battery light or charging light can be due to worn or sticking alternator brushes not making proper contact with the rotating part (slip rings), which results in intermittent or low charge and eventually a flat battery.
Also check the alternator drive belt.


Bill G Melbourne Aus

[t_marat]

You would travel only a few kilometres at most with alternator not charging.
Flickering battery light or charging light can be due to worn or sticking alternator brushes not making proper contact with the rotating part (slip rings), which results in intermittent or low charge and eventually a flat battery.
Also check the alternator drive belt.


Bill G Melbourne Aus
Well, why did not I get the warning light at all? I mean the battery warning light? It should have been on, showing that I am running on batteries?

Another problem. My car is currently at a country side. 70km away from the city. There is no one who could handle my car there, so I have to bring it home somehow. I bought a new battery, fully charged. Will charge my old one and will try to get to the city using just the battery power. Will it work, or will I get stuck somewhere in the middle?

The new one has a rating of 75 ampershour, the old one is 90 ampershour.

[t_marat]

There is also one loose harness, cable with 3 contacts. You can see from the picture. From where is it? I can't find any receiving connectors anywhere near.

[Beemr750]

Thereis a very simple way to check your charging
ability.First with a voltmeter take the battery voltage with no load on it (nothing turned on).
Start up the engine and go to about 1000 Rpm.See what the meter reads then,it should be above batt.voltage at least over 13.5.Now to find out if the alternator is a good one,turn on as much as possible(lights,radio,a/c etc.) at this speed or a little higher it should hold the same.If your alt. is weak or has a faulty regulator or bad diodes,it will show only batt.voltage.

[632 Regal]

yes, check with a digital multimeter and if its not around 13.5 then id say your alternator has failed. You can rebuild the old one or get a replacement alternator. This shouldnt be a hard project to replace at all, make sure you disconnect the battery before working on it.

[t_marat]

I did that check and there is absolutely no difference in voltage with engine off or on.

And by the way, I drove on batteries only (alternator not functioning) about 80kms back home from the country side! :) Bought a spare battery in case the old one runs dry.

I was advised a new alternator will cost about 800$!!!! The car costs about 6000$.

[shogun]

Can you get a regulator in your area? that is most probably the culprit. At least I would try to change it. If you are lucky you get one for for 25 $.
http://www.autohausaz.com/search/productx.aspx?sid=f5ksnpfu5j40y2555pvvki55&makeid=800003@BMW&modelid=1012071@525I&year=1994&cid=18@Electrical%20%26%20Vacuum&gid=4884@Voltage%20Regulator

[t_marat]

Maybe it is unrelated, but it has been several days that the engine does not stall in idle. Previously this would happen when the rev was coming down from somewhere like 2500-3000. This would happen only when the engine was hot, not while it is cold. For the past 2 days idle never stalled. Can it be related to the fact that I am now running on battery only?

[632 Regal]

your alternator may actually be working at times and not completely dead, just staggering around like a drunk at happy hour.

[t_marat]

what do you think of that loose connector? is it supposed to be like that?

[t_marat]

And also, how easy is it to remove the voltage regulator? Is it possible to test the alternator and the voltage regulator not removing them from the hood?

[632 Regal]

well no change between sitting and running is a good sign that somethings definetly bad....what was your other question?

ahhh the loose connector, thats a good question. I dont think mine has any connectors down there.

[t_marat]

This is the picture of my alternator. As you see the part is very worn. That is the thing onto which the two little black things go on. They provide contact. I don't know how they are called in English.
Mechanic says the fix he did is only short term, that I will need a new alternator soon.

[skr]

are those the slip rings? now, that's a lot of wear. what was the condition of the brushes?

[t_marat]

One was good. The other, which was in contact with the slip ring with the most wear (the inner one) was really bad.

I can't understand what made those slip ring to come to that condition? I am not an electrician but every electrical staff that I saw showed wear in the brushes, not in the slip rings.

[Anthony (M5 in Calgary)]

One was good. The other, which was in contact with the slip ring with the most wear (the inner one) was really bad.

I can't understand what made those slip ring to come to that condition? I am not an electrician but every electrical staff that I saw showed wear in the brushes, not in the slip rings.

That wear is caused when the brush reaches it's wear limit and begins arcing (wire inside the spring stretched to the limit). The arcing erodes the slip ring, making the groove you see. It's a good idea to check your brushes and replace before they wear out.

[t_marat]

the brush causing the arcing has been replaced with a new one. how long do you guys think this slip ring can last?