Check all the terminals from the alternator to your battery. Because it might be rusted and the alternator isnt charging the battery, that happened to me on my + terminal near the drug-bin.

 

Definitely, already checked, but good thinking!

 

It wouldnt hurt to replace the fsu since its known to drain batteries.

 

Sorry for being away everybody, it's been a very busy weekend/week. Thank you for all of your replies, they have definitely reinforced my own assumptions.





That's good thinking. I haven't had the chance to check the current once the computers goto sleep, I plan on doing this soon, however.

I would start by replacing the battery. At this point, it's hard to tell if it's your battery not charging or the system not producing enough charge.
Replace it, get or find your voltmeter, install the battery and check the voltage then. If with a healthy new battery, your system does not show 14v or so you know for sure your charging system needs checking.
Most batteries after being drained a few times may have a damaged plate and will not hold a charge, will not charge, or will charge only partially.

I ran my float charger on the battery and it charged to about 12.6V at the front jump points - which is (from what I've seen personally and researched) usually .5 lower than voltage at the battery. However, I did notice that in the morning after the charge, the voltage had dropped by approximately .6 volts overnight. Although my alternator may be about to 'buy the farm', I wonder if I still have a drain/bad battery. I'll guess I'll test the current load and then replace the battery based on my findings. Unfortunately the battery is actually still in warranty but the PO didn't keep the receipt with the battery so no-can-do for a return :banghead:

Ed, try doing the cluster test on your alternator.

And, OP, 13 V is a bad alternator. When running, you're using the alternator to power the car...anything left over goes to the battery...but you won't have much left over. Won't say it's not the battery too, since if the alt is failing, the battery has been probably running lower and lower and as a result the alt is working more and more. If you're really at 13V (confirm) directly from the alt, then there you go.

I'd charge battery, replace alt, and see where you end up. HTH

Hey Dmax, I ran cluster test 9 yesterday when we were out for my son's Dr. appt and it was registering between 13.6 and 13.7 volts @ 2000-2500RPM. Any more comedy club videos coming out soon?

You do not need an alternator.

If the alternator was the problem, it would turn the Charging System Failure light on (the light that looks like a battery).

It is very rare that an alternator works poorly, it either works or it does not. Having said that, I recently had an alternator issue where one of two brushes had worn out, so my alternator was working poorly, so it is not written in stone that an alternator either works or does not -- but in all of my years working on cars, my experience is that an alternator is a go-no go kind of device.

You should be looking at the output with the engine operating at about 1500, or so, RPM. You should also turn on as many electrical loads as you can think of -- lights, fans, etc. At 1500 RPM, the alternator should have an output of 14.5 volts.

The short trips of just a couple of minutes is very hard on the battery, and it is also hard on motor oil. I am not an advocate of the 3,000 mile oil change, but the way your wife uses the car it would be a good idea if you changed the oil early and often. I also have a 'vert that spends several days, weeks sometimes, in the garage waiting for a sunny day and my need to be someplace else to happen at the same time.

JD, as you can see from my reply to DMAX, my alt voltage is low around 13.6 while running. and there most likely isn't much left over for the battery to charge. I run 4500 mile oil changes in both the X and the E46. The X is used for all of our family trips, but those don't happen so often, so usually it's driven to the gym and the play dates etc. A relatively unexciting existence for one of the most gorgeous SUV/SAV's I've ever seen (Alpine White, gets me every time). :thumbsup:

 

G'morning all,

I'm having a starting issue with our 2005 X5. (M54B30, 160,000 Miles, Automatic w/step)

Although not specifically an E46 question, the E53 x5 in question is of the same generation and has the 3.0 M54 motor.

The car is having starting issues, directly caused by a low battery charge. Lets say I jumped it this morning (which I did) and my wife and son take it to the gym, it will restart and get them home as well as restart throughout the day just fine. Additionally, the car will start perfectly the morning after a day of in-town driving, but only once. I started the car before I left, but then it wouldn't start when my wife went to leave 30 minutes later.

The starter doesn't struggle when it does start and no issues arise when driving. I have only seen the battery light during the pre-start dash test, and never once while driving.

I took the car to O'riely's to have them test the battery / alternator (as I couldnt find my multimeter), their tester was on the fritz, but the salesman said the battery reported good but needed a charge. We cranked the car and he tested alternator voltage (which I confirmed via the OBC self-test). The alternator voltage was slightly low at around 13.0V rather than the nominal 13.5-14.2...ish. However, this should still be enough to charge up a 12V battery, albeit more slowly than with the alternator at nominal output.

My three hypotheses are thus:

1. Bad battery - although it tests good, and is about 3 to 4 years old, might not be holding a propper charge.
2. Bad alternator - possible because I have a power steering system leak and there is ATF sludge on the alternator, but output seems ok with no issues while driving.
3. Current draw/drain - something may be staying on/ coming on and pulling the power/grounding out.

The car does enter sleep mode fine and the FSR/FSU is not making any alarming noises while running, nor turning back on after shutdown as it did when it when out in the 325. I have considered the BMW Assist/TCU module, glovebox light, sludge on alternator grounding out the generator.

I'm sorry for the long post, but I wanted to be as thorough as possible. Any ideas or confirmations about what is most likely happening?

I would start by replacing the battery. At this point, it's hard to tell if it's your battery not charging or the system not producing enough charge.
Replace it, get or find your voltmeter, install the battery and check the voltage then. If with a healthy new battery, your system does not show 14v or so you know for sure your charging system needs checking.
Most batteries after being drained a few times may have a damaged plate and will not hold a charge, will not charge, or will charge only partially.

 

+1, plus some more.

When the battery dies, it almost never dies all at once, it will die slowly. You go out one day and need a jump-start. All is okay until yo come to a weekend where the car is parked for three or four days in a row then you need a jump-start again. After a few weeks of this, the jump-satarts get closer and closer together until finally you need a jump for every start.

Short trips make the jump starts come sooner, long trips put the next jump an extra day or two later. Jump starting a car that is only heading down to the local 24-hour Fitness a mile or two away is a bad plan that gets worse when your wife or daughter is making the trip because that trip is too short to recharge the battery enough to have any sort of reliability.

You have described a dead battery. And, a short inside the battery can pull the voltage of the system down, even if it is otherwise healthy and strong.

 

Permit me to jump in here too, as recently I have had a really odd version of this with my wife's 04 325Ci convertible.
Keep in mind that she works about a quarter mile from home, and often walks to work. On weekends, we tend to drive my X5 for shopping, so other than when I think to do it, and since we are only now getting into tops-down weather, the car sits for a few days at a clip without being driven, then only for about 10 minutes, and then (5 hours later), 10 minutes back.
She has had a couple of no-start situations. And now I put the battery on trickle charge via BMW Charger that works through the 12 V cig lighter plug.

BUT it ALWAYS needs a charge according to the light on the charger. I also have an "industrial" charger, and when it's dead, it drops to nearly zero charge, but comes back up to full in a pretty short amount of time..

Battery is 2 1/2 years old, and is a BMW OEM battery for convertibles (different than coupes or sedans).
Alternator was tested, no fauilts recorded.
Power tracking meter was put in series to test for any drainage by any electrical components (for three days), not a single blip.

So I'm wondering if her short trips (on a nearly 10 year vehicle, but with less than 50K miles) suddenly is presenting a gremlin or should I just replace the alternator, belts, and battery again....?

Thanks for your feedback.

ed in NJ

 

You do not need an alternator.

If the alternator was the problem, it would turn the Charging System Failure light on (the light that looks like a battery).

It is very rare that an alternator works poorly, it either works or it does not. Having said that, I recently had an alternator issue where one of two brushes had worn out, so my alternator was working poorly, so it is not written in stone that an alternator either works or does not -- but in all of my years working on cars, my experience is that an alternator is a go-no go kind of device.

You should be looking at the output with the engine operating at about 1500, or so, RPM. You should also turn on as many electrical loads as you can think of -- lights, fans, etc. At 1500 RPM, the alternator should have an output of 14.5 volts.

The short trips of just a couple of minutes is very hard on the battery, and it is also hard on motor oil. I am not an advocate of the 3,000 mile oil change, but the way your wife uses the car it would be a good idea if you changed the oil early and often. I also have a 'vert that spends several days, weeks sometimes, in the garage waiting for a sunny day and my need to be someplace else to happen at the same time.

 

Ed, try doing the cluster test on your alternator.

And, OP, 13 V is a bad alternator. When running, you're using the alternator to power the car...anything left over goes to the battery...but you won't have much left over. Won't say it's not the battery too, since if the alt is failing, the battery has been probably running lower and lower and as a result the alt is working more and more. If you're really at 13V (confirm) directly from the alt, then there you go.

I'd charge battery, replace alt, and see where you end up. HTH

 

Oops...OP, JD is right...you'd have a battery light on if it's the alternator...although, 13V is low and it still sounds like the alt to me...combined with, as mentioned, maybe too many short trips and not enough long ones. Do what JD said and see if you see a higher Alt voltage.

When my alt failed, I got the light flashing, then off, then on, then off...until 10 miles later, it just stayed on. It doesn't sound like a healthy alt to me, but JD knows his stuff so I can't argue with him...I can 'just say.'

 

My alt was at 13.6 or so for at least a year or more...just bought the farm a few months ago...an original alt at 240K miles or so.

So it's a little low, but substantially better than 13V.