alternator question
 

My 3.0 x5 shows 119 on code 9 which indicates my new battery only has 11.9 volts. I put it on the charger to see if it shows anything different. Just hooked it up and shows 119 still. Should I charge it overnight and test it again? The production date is 3/2000 and has one button to reset the mileage and no second button. I'm trying to determine if the alternator is gone. I can go to Autozone once the battery is charged and have them test it or I can try out my new Schwaben/Foxwell scanner if I can figure out the instructions. Any insights on verifying alternator output?

Using the hiden menu or scanner is not the greatest way to diagnose alternator or battery issues. What is voltage when engine is running? What problems are you having?

After driving 50 miles on the freeway and stopping for about an hour I restarted the x5 to head home and no defroster fan. This has happened intermittently for a while. It could be a big problem shortly if we have a deep freeze. I'm checking on the alternator output after replacing the battery that only produced 300 CCA and was rated at 900. The fan replacement is pretty involved compared to the e30 and e34 projects I've done in the past.

Foxwell will make a graph of voltage. You can catch dips after the fact


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I need to figure out how to get that from my scanner.

alternator question
 

There are a bunch of modules that have voltage.

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The last pic most interesting: the two dips to 13.0 happened exactly when I switched from throttle on to coasting. First when stopping to turn out of a parking lot, second to park at a curb

Notice that in normal driving the voltage stays within 0.2 v min to max. The voktage regulator changes the field voltage of the alternator to change the output voltage of the alternator, this way it can make maintain steady output voltage no matter what the rpm.

The alternator makes 3 phase AC at I'm guessing 100-400 Hz never measured but I think I've heard it. That voltage is converted to DC by a 3 phase bridge rectifier built into the voltage regulator.

The voltage regulator increases the voltage hence current to the armature of the alternator any time the output voltage is lower than desired output.

The only reason for the dips is some built in lag to smooth out the controller so Its not wandering around all the time.

When you drop throttle and it normally drops to 13, when the slip rings are worn the field current will get weaker than needed to maintain output and you will get a drop low enough to trip codes.

What scanner did you use to get the graphs? Mine is a 14020SCH small hand held unit. Their instructions are not the best and I haven't found the location on the menu to test the battery voltage. I just got it so I'm not that familiar with it's functions.

Yes, charge it and see if it takes a charge. It should be 12.4 or better. It is an old battery. 18 years is long past its expected service life. I would put in a new battery just because of the age. You could also have an alternator problem. Easiest way to tell is to fire it up and use a multi-meter to check the voltage at the jumper points under the hood. You should be seeing at 13.5 at idle.

The battery is a week old. I charged it last night and the heater fan worked on the way to church this morning. I will test with my meter to see what the alternator is putting out.

Sorry, misunderstood. Thought you meant battery production date. :D

Wonky fan operation the prime suspect is FSU.

I misread the 18 year old battery at first also


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alternator question
 

I use foxwell NT510. I can achieve the same with wifi obd dongle and dash command on my phone.

In the engine module there is an engine operating values includes vbat but many modules will have. Very helpful to have both rpm and vBat.

The graph at start-up is very interesting I'll have to redo that.

If FSU is "Final something Unit", That got replaced last Summer.
It's the small bed of nails that goes in the passenger footwell.

Mr. Schwaben and my multimeter both say 13.9 volts. I'm guessing I either have a dying heater motor or a parasitic drain of some sort. The rear defrost indicator, and the two additional indicators above(?) it will flicker most of the time when I'm having the no fan situation. I found the Schwaben information on the "Live Data" choice.

Final stage unit. Sometimes erroneously called the FSR or final stage resistor is often called the hedgehog or porcupine.

If you are having blinking in the lights on the controls I would suggest a problem with the control panel. You should be able to direct drive the blower with your scanner is it's similar to the foxwell.

The Lord works in mysterious ways.

Fun comment made me laugh

Weak Alternator Can have strange effects
 

I am about to install the third alternator in my X5 3.0 in 5 years. The first two were Bosch and both lasted about two years. Fortunately for FCP Euro, The last two were replaced free (except for labor of course!) Now, they’re sending me a Valejo, today, which is supposed to be OEM, at no additional charge, With free replacement Under their lifetime warranty.

However, In the last two days, I got a Stanley battery charger at Walmart which showed something very interesting. I have been having misfire problems for six months and weak power. Three different mechanics couldn’t diagnose it.

In order to get around during the last 2 days, I charged up my one year old Diehard Gold battery to 100% and- to my surprise, my performance and power issues disappeared. That is, until the battery voltage went down again below 10 volts On some local trips. By The way, 100% recharging took at least 24 to 36 hours.

I’m looking forward to getting the new Alternator and hoping that my power problems are gone. I never suspected that it might be an alternator problem, But if the spark plugs are not getting enough power, I can understand it.

The Stanley charger also diagnosed the alternator is being bad. My little Ebay digital voltage meter in my cigar lighter also allowed me to tell when I was about to run out. I hope this helps someone...