Regualtor brushes after 180k km-pics

[shogun]

Changed on the weekend together with my backyard hack mechanic buddy 'Take' on his 750iL Highline the regulators on both alternators.
Yes, the car is a Highline version and has 2 alternators and 2 batteries.
180k km is just over 100 k miles.
Voltage was under 12 V, EML came up, engine ran in limpmode because of the too low voltage
And it took us just over 5 hours :) :(
Here some pics of old and new regulators
http://img97.imageshack.us/my.php?image=hellaboschalt26lz.jpg
http://img75.imageshack.us/my.php?image=hellaboschalt31jg.jpg
http://img97.imageshack.us/my.php?image=hellaboschalt29xa.jpg
http://img97.imageshack.us/my.php?image=hellaboschalt10xa.jpg
http://img97.imageshack.us/my.php?image=hellaboschalt2op.jpg

As you can see, the new Hella regulator has a resistor installed, that has 22 Ohm and is there to dampen sudden impact in change of charging (so to speak in my simple English).
We did it as described here http://bmwe32.masscom.net/sean750/VoltageRegulator/VoltageRegulator.htm

Unfortunately, the main alternator is still giving max 13.5-13.8 V, even at high speed on the Highway with high RPM, no more EML light, starting is better, but not the full voltage.
The small alternator is fine now.
Looks like a diode in the main alternator is damaged. So we have to do the same "fun" next weekend again, but then we will install another alternator from my spare car with a new voltage regulator. Lucky that I just imported about 20 Hella regulators from Germany for myself and friend from the Club.
So better check your regulators and brushes. On any other car than a 750 it is an easy job.

[joshua43214]

Umm 13.5-13.8 volts is correct voltage. not sure what you are unhappy about. good work either way. v12's are always fun to play with.

[shogun]

Well, I do not have a Fluke DMM, so the 30 $ DMM might be wrong somehow a bit.
But the smaller alternator for the 2nd battery is producing more than the one which is for the main alternator.
And 13.5-13.8 is the MAX I can get at any RPM from the big one.
The difference of 0.6 V is too big.

I am not good in electrics and electronics.

The following are the detail figures I use for my own evaluation:
With key out of ignition switch, should see 12.4V or above. 12.0 V is getting low.
With key inserted and turned to position 2 (don't start car), should see 12.0V or more. 11.6V would be too low.
Crank car, catch the lowest voltage reading during that couple of seconds. Should see 10.0V or above. 9.5V would be marginal.
The above just consider the health of battery itself.
And that of course depends on ambient temperatures, age of battery etc.

Car running at 1500 RPM or more, should see 13.7 to 14.3V, 13.6V or below means the charging system is weak.

Any comments from electric specialists wellcome.

[Jon K]

Well, I do not have a Fluke DMM, so the 30 $ DMM might be wrong somehow a bit.
But the smaller alternator for the 2nd battery is producing more than the one which is for the main alternator.
And 13.5-13.8 is the MAX I can get at any RPM from the big one.
The difference of 0.6 V is too big.

I am not good in electrics and electronics.

The following are the detail figures I use for my own evaluation:
With key out of ignition switch, should see 12.4V or above. 12.0 V is getting low.
With key inserted and turned to position 2 (don't start car), should see 12.0V or more. 11.6V would be too low.
Crank car, catch the lowest voltage reading during that couple of seconds. Should see 10.0V or above. 9.5V would be marginal.
The above just consider the health of battery itself.
And that of course depends on ambient temperatures, age of battery etc.

Car running at 1500 RPM or more, should see 13.7 to 14.3V, 13.6V or below means the charging system is weak.

Any comments from electric specialists wellcome.


Shogun let me chime in here a little bit -

With the key off, car off, the battery should read 11.6 - 12.2, if you're reading much over 12.2 or so your system can be overcharging the battery (failing battery) and can cause problems. Remember, even though the car runs and makes 13 - 14v, the battery is a 12v battery - anything over those 12v are not necessarily being absorbed by the batter. 11.6 on a battery with no alternator running is good - go open a brand new 9v battery and use a multimeter, they're usually 8.75 - 9v but rarely over 9. When cranking the car, the voltage you see is useless... it actually will dip as low as 7v or so... that is why some devices like radios or amplifiers that require a 8v+ signal to turn on don't turn on until after the car is running a few seconds. With the car running at 1500rpm, seeing 13.6v is fine. Yeah the "charging system" isn't near it's 14.4v theoretical maximum, but still, there is asbolutely nothing wrong with 13.6v. More important than the voltage in your case is amperage. Your HighLine has a lot of stuff it is powering which does not necessarily draw much voltage but draws amperage. If you do end up replacing alternator(s) upgrade to higher amperage models.

For instance I upgraded form a valeo 90A or 110A or something low to a Bosch 140A. Both units produce the same voltage (albeit the bosch will do so for longer hehe) but the Bosch creates more amperage which will allow more draw at any one time. if you're getting 13.3+ at idle, with your big car with lots of electronics, i'd say that's good.


Oh yeah - one morr thing - I had issues with low voltage (to the point where the car would not charge enough to stay running). Rather than screw around with voltage regulators for $70 and see if it fixed it, I decided to just replace my whole alternator with the Bosch 140A model. If you have a Valeo model and go to the Bosch model, you must also get a Bosch alternator pulley, the Valeo does not fit the Bosch unit. Good luck!

[632 Regal]

I believe 13.8 is a maximum figure before over charging will become a problem.

[shogun]

There is a 140A Bosch alternator installed in each Highline, plus the other smaller alternator.
And the Hella regulator shows 14.1 V printed on it
http://img97.imageshack.us/my.php?image=hellaboschalt2op.jpg
The alternator (140A) showed before (when it was o.k.) always more than now even after changing the regulator.
And the funny thing is that the smaller shows more voltage charging than the large 140A. Even if I deduct some error by measuring on different contact surfaces and the DMM is just a normal one and no Fluke or so, the difference between the 2 alternators is significant.
As I said, 13.5-13.8 is max., but in idle it it is abt 12.8 V only and depending on RPM it goes to about 13.5-13.8V max.
That is not normal. I checked with my 750 (not Highline, only 1 alternator, but 140A too)car also, so we have a comparison.
The 750 electronics are very sensitive with regard to too low voltage. I read that if the voltage is for more than 90 seconds below 11.7V, the engine goes automatically into limpmode. And we had the case now before we changed the regulator.

I do not pay $ 70 for an alternator, I buy the Hella directly from Germany from a wholeseller cheaper.
We will check this week again and maybe we change the complete alternator to one I have on stock from another parts car, also 140A Bosch.
That is the good part, if you have one or some parts cars ;-)

Thanks for the input.

[Javier]

My car voltage, read with the OBC, is between 14.05 and 14.25 almost all the time.

Javier

[genphreak]

My car voltage, read with the OBC, is between 14.05 and 14.25 almost all the time. Javier I wonder how the two alternators share the load- being different sizes. Perhaps the smaller one tends to generate a greater share of the total current at lower rpms and the larger start to cut in once the smaller one is on maximum output. Just a thought, seems that Erich was thinking that their respective loads might be an issue since he is not 100% about the health of both alternators now the regulators have been replaced.

I imagine they both work sense the voltage drop and cut in oblivious of the other generating current into the circuit or not- would you be able to shed any more light on how they might work in natural operation Javier? :) nick

[shogun]

The main alternator has 140A and the additional has 32 A, so in total 172A.
I only know that there is a separation relay which cuts off one battery when engine is not running and both or one battery is going too low, so that it is ensured that the car can be started. So probably the unneccessary items will be cut off in such a case when battery goes low respectively both. This relay is also there so that one battery cannot draw power from the other battery and both can go weaker, I have heard.
The car in question was built in 12/1992, so a 1993 model year. Here are the wiring details if you really want to know the details
http://www.e38.org/e32/e32_93_etm.pdf

[Jon K]

There are probably two different circuits for each alternator. It's really odd that BMW would use a 140A and a 32A alternator, when there are 200A alternators readily available even back in the day of the E32.

[shogun]

That car has a lot of 'double/excess parts' if you just want to make a cheap engine. For example the system is layed out in such a way, that each 6-cylinder section can run on its own. So even if one half of the 12 cylinder engine fails, the rest of it is equipped with all needed.
2 fuel pumps, 2 fuel filters, 2 fuel relays, 2 MOTRONICs, 2 distributors and rotors, 2 throttling valves and so on.
And all is coordinated by the EML unit.
Quite interesting stuff how that works, here is a good write-up
http://www.europeantransmissions.com/Bulletin/DTC.BMW/EML-BMW.pdf

and testing alternators
http://www.tpub.com/basae/32.htm

[genphreak]

Well I'm always keen. PDF taking a long time to load tho, maybe my reader is crashed again.

Still, I have to say I like the idea that it the car has (almost?) 'komplet' redundancy in critical systems. A great selling point I guess, especially to public figures and execs with big opinions of themselves... and certainly to armoured limo manufacturers. Not that there were so that many of these... it would have been interesting to be a fly on the wall in BMW AG marketing dept around this time... indeed, is the current 750 still like this or has the whole concept been dropped now? Maybe the 10 cylinder will take over now that is in full-scale prodcution, if not already. Certainly fun Erich, I expect that these cars will be worth a mint within a decade, when other petrol-burning cars risk being valued by the kg (ie for scrap)... :) Nick