Battery vs.Alternator vs Starter???

[Bmwtvboy]

I imagine there are some posts on this: 01'3.0,191K,auto
X doesn't start after sitting with minor draindoors open, lights on etc.)
Full electric power to turn on all accessories, but not enough to start. Makes a clicking noise. Hooked up a drip charger, one hour later, started right up.
Question: How does one know if the solenoid / starter is at fault vs. the battery/alternator? Battery is aprox. 3 years old. All other components are original. Thank you.

[David.X5]

I believe these cars have a circuit to protect the electronics that keeps it from cranking when battery voltages drop. I would start by measuring the battery voltage while sitting and then when running. You can probably find more specific numbers, but battery voltage sitting should be above 12 volts and then increase to around 13.5 once it's started and alternator is running.

If initial voltage is low and goes up a little, could be bad cell in the battery. If the voltage doesn't go up at all then suspect the alternator. Many of the local parts places will put an electronic tester on the car to test the battery for free. They can also test alternators, but since our alternators are the weird water cooled model, it is a big pita to remove to test.

If you can measure the sitting voltage and running voltage, you will probably get more specific advice. My initial gut feeling Is to focus on battery and not starter or alternator.

[cn90]

Most modern BMWs (1990s---> current) suffer from FSR shorting out.
So, sit in the car with door closed, if HVAC blower motor runs with HVAC panel off, then FSR is shorted.

Otherwise, you have to do some trouble-shooting to figure out where the current drain is.

[Bmwtvboy]

I had the battery checked: bad cell. BMW battery 690CCA. Battery drain test: 390 Amps. It was put in 4/08, not bad. Putting in a new battery. Checked charge at jump post and battery before taking the old one out;13.99 volts. How do you check parasitic draw if there is a security system,dome lights etc and the battery is in the back? I was advised to check draw off negative terminal. A few months ago I installed a new media bridge Dice unit that has been working fine. Because it connects through the rear CD player power I figured it is wired the same as the radio.
Anyone had problems with these aftermarket units? Thanks.

[David.X5]

Seems like good news. Pretty easy repair and not too pricey compared to alternator or starter.

If the battery has a bad cell, you may not have a parasitic drain.

Measuring the drain is a little tricky as you have to insert a current meter (current setting on a decent multimeter will work) between the battery terminal and cable. Don't try to start the car like this - the minimum is you will toast your meter, and can start a fire or other bad things.

[Bmwtvboy]

But inorder to find proper draw, don't I have to disconnect security/dome lights? BTW, does anyone know what draw is for the older x? I believe most standard cars are 50ma. But Bmw I believe draws a bit more after sleep mode

[omodos]

hey fella, well ahhmm posts everywhere I read say draw whilst x5 asleep should be below 50ma, and in posts i read where people have cured their drain issues the draw is 25-29ma (please correct me if I am wrong anyone out there who disagrees)

Dome light? nope, I engaged the lock in the rear and left the passenger side door open , waiting 15-16minutes and the light near gear knob was off so x5 asleep, opening the glovebox to check fuses i found the glovebox light stays off so x5 still asleep...then proceed to test fuses

[Bmwtvboy]

That's great.. I didn't know it would sleep if left open. That explains no lights after an hour of trying to drip charge the battery when all was open. Darn, I hope I needed a battery. This start things was intermittent.

[omodos]

Originally Posted by Bmwtvboy

That's great.. I didn't know it would sleep if left open. That explains no lights after an hour of trying to drip charge the battery when all was open. Darn, I hope I needed a battery. This start things was intermittent.

Mine does sleep, I leave a door open after 15-16mins when i open the glove compartment the light is not on so must be asleep...and the orange light near gear stick is off....my start thing is not intemittent, for sure when the temps drop it suffers wont start

[Harry.s.truman]

I had an issue like this that snowballed.... In the end, I replaced the starter, battery & alternator....

All three were going... The main culprit was a corroded connection at the jump post under the hood... Cleaned that and it solved my issue, for the most part, but while I was charging, checking and diagnosing , I prob killed the starter and alternator...


Couldn't figure out that a bad connection was causing all these issues..