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X3 F25 (2011 - current)
The latest X3 brings some added style and some new features to the BMW SUV family. Talk about the new F25 now!

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  #26  
Old 12-19-2013, 04:53 PM
ngrigoriev ngrigoriev is offline
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Third day so far...the car is still at the dealership. They are testing it. Looks like they have got so overloaded with other cars so they are just making it through the backlog But at least I have got a better loaner - a fresh X1 instead of a bit used Dodge Avenger. At least this is something I can safely drive in this climate.
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  #27  
Old 12-20-2013, 12:15 PM
ngrigoriev ngrigoriev is offline
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OK, it is official - 3 days later the dealer says they have found nothing wrong, except the short trips....I am getting the car back today. No explanation why the car has suddenly died after starting cold in the morning without any complains

I think I will be charging it regularly, but not more often than once in a couple of days (otherwise what's the point - this is not a plug-in electric car! ). And then we'll see if the problem reappears.

I have got a silly question for the car experts. Is there a way to test the battery manually? I have a digital multimeter. And is there a way to find out if the charger is doing its job properly? I was surprised that my BMW charger was stopping to charge the battery only after a few hours.

I will probably discuss with the dealer the possibility of getting the preheater/charger accessory, for convenience. But not sure I want to pay $700 for it...
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  #28  
Old 12-20-2013, 12:46 PM
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AzNMpower32 AzNMpower32 is offline
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Quote:
Originally Posted by ngrigoriev View Post
OK, it is official - 3 days later the dealer says they have found nothing wrong, except the short trips....I am getting the car back today. No explanation why the car has suddenly died after starting cold in the morning without any complains

I think I will be charging it regularly, but not more often than once in a couple of days (otherwise what's the point - this is not a plug-in electric car! ). And then we'll see if the problem reappears.
Actually, with these new BMWs, they sort of did create the first plug-in car. After my father's 2010 X5 battery died (dealer said it was our fault.....gave a few lame reasons, did goodwill on the battery), he plugged the battery charger in every weekend. "The world's first plug-in vehicle........"
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  #29  
Old 12-20-2013, 03:43 PM
The X Men The X Men is offline
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Quote:
Originally Posted by ngrigoriev View Post
I have got a silly question for the car experts. Is there a way to test the battery manually?
After you fully charge the battery, put you DC volt meter across the battery, you should get around 13 V. Let it sit for an or two, if the voltage drop a volt or two, you probably need a new battery or you have a draw on your electrical system when the car is off. BMW, do you have any after market accessories on your car?
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  #30  
Old 12-20-2013, 04:30 PM
ngrigoriev ngrigoriev is offline
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Here is the final report from the dealer. From now on I can refer to myself as "poor driving profile" for BMW.

Class action, anyone, seriously? I mean - we do not need to demand anything unrealistic, like "getting it right". I do not think we need to ask BMW to replace the "broken cars". But here is how would I see it personally:

- ensure that BMW replaced the batteries during entire warranty period even if they fail because of the "poor driver profile"
- BMW makes adjustments to reduce the discharge effect to minimum: replacing the batteries with more reliable ones or the ones that better hold charge in cold climate, adjusting power saving mode of various components and/or allowing people to control it better, fixing alternators, whatever else that would minimize the negative effects of the "short trips" - even at cost of slightly greater gas consumption
- if they cannot get their car to work like a car that costs 1/4 of their price, then they at least need to supply the customers affected by the issue with a certified charging device and provide a convenient way to charge the vehicle outdoors. Some sort of well sealed weatherproof plug etc.

Basically, if you cannot make that thing work like other cars - at least make it as good as possible and make the extra steps the owner needs to take to keep it in shape as painless as possible.
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  #31  
Old 12-20-2013, 11:27 PM
newyankee newyankee is offline
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I just have 1000 miles on an X3 in a moderate climate, so no battery problems yet. But if I were confronted with a dealer claiming "poor driving profile", I would respectfully ask for complete engineering specifications for the battery and charging system, plus the source code for the car's computer that flags the "poor driving profile" conclusion. I suspect that they would prefer to replace the battery rather than expose their source code to the likes of the technical folks in this forum.

FYI, I keep a small digital voltmeter plugged into the front cigarette lighter plug. I routinely see 12.2V before I start the car, and a quick increase to just under 15V when the motor is running. I believe any future battery decline will be revealed by a change in these routine readings.
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  #32  
Old 12-21-2013, 06:36 AM
The X Men The X Men is offline
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Cannot have a class action suit if its only a few isolated case.
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  #33  
Old 12-21-2013, 03:46 PM
ngrigoriev ngrigoriev is offline
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Quote:
Originally Posted by The X Men View Post
Cannot have a class action suit if its only a few isolated case.
Depending on how few. Also, if it is few case - there is even more reasons for BMW to address them. At the end, all I (we) want is to have a car that functions as normal car. Our previous car had comparable amount of heavily consuming equipment and it did not have any winter start problem for 4 years.

Speaking of the voltage, I have measured it this morning. Battery: 12.29V, lighter socket few seconds after start: 13.91V.
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  #34  
Old 12-22-2013, 05:34 AM
The X Men The X Men is offline
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Quote:
Originally Posted by ngrigoriev View Post
Depending on how few. Also, if it is few case - there is even more reasons for BMW to address them. At the end, all I (we) want is to have a car that functions as normal car. Our previous car had comparable amount of heavily consuming equipment and it did not have any winter start problem for 4 years.

Speaking of the voltage, I have measured it this morning. Battery: 12.29V, lighter socket few seconds after start: 13.91V.
Another way to check the battery is to measure the voltage, discount the battery, wait a day or two, the battery should hold the voltage within a few tens of millivolt.
You can also check for parasitic current draw by hooking up a ampere meter to the battery or measuring the voltage after you shut off the car and then again the next day.

Last edited by The X Men; 12-22-2013 at 05:40 AM.
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  #35  
Old 12-22-2013, 12:10 PM
Gouda Gouda is offline
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I put our X3 on a trickle charge and let it sit for three days. Today I went to measure the current draw. Used a Fluke clamp on amp meter which I know from previous use is accurate. With only the hood open, I could measure no current flow (meter measures down to 1/100 if a amp.). With the drivers door open it measured .02 amps. The dash had not lit up at all. Only the entrance lighting. What does it mean, humm to me it seems that there is no signifant current draw when idle. So, why do people have issues? I have no idea, but plan on doing some more measurements over the next few days. I wonder if there is something that cycles on and off. Any ideas? Our X3 is about 32 months old with the original battery.
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  #36  
Old 01-07-2014, 04:21 PM
ngrigoriev ngrigoriev is offline
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Just found an interesting page talking about the X3 electrical system. Probably nothing new for the experts but I have found a few interesting things there for myself:

http://www.bmpdesign.com/technical/e...cal/bmw/x3.php

I am still watching the car. So far so good but I am charging it too often. Will talk to the dealer soon, still have some questions about the battery incident we had back in December.

Also need to fix the rattling sunroof and reprogram this silly stop/start engine system to remember the last user settings. Otherwise it sometimes shuts down the engine after driving for 800 m from home when it is -4C outside - certainly not good for the battery.
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  #37  
Old 01-13-2014, 06:37 PM
ngrigoriev ngrigoriev is offline
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In last couple of weeks I have learned quite a bit about this car's electrical system. And I had a chat with BMW service supervisor who explained me some details to complete the picture.

The problem we had with the car being unable to start on a cold morning after a short trip has not reoccurred (so far) BUT I have found two more people among the friends and colleagues who had _exactly_ the same issue and one more who was just unable to start the car on a cold morning. Lucky guy, he could at least stay warm

Officially the dealer is unable (or not willing) to explain what happened. To be fair, they do not know for sure, they admit it. When the car got to the dealership they have measured the battery being at 82% (!) and the "startability" factor calculated by the car was at 38%.

My current theory is that because of the STUPID (yes, I believe this is stupid if it results in such a problem) design this car was, essentially, running off the battery during the most of the short trip on the cold morning. And, since all heating stuff was on (the driver wanted to avoid freezing! ) the battery drained like hell. Again, due to STUPID alternator delay logic and because the RBS that is not active until it warms up, this short trip has caused an excessive drain on the battery. And the alternator has started to produce some electricity only when my wife was actually approaching the parking. So, the car was stopped, locked, the battery was continuing to drain (it takes 5 minutes before most of the stuff goes to sleep). So, after few minutes the battery was nearly dead after such a shock.

Also, since it is all about chemistry, after about one hour the battery has somehow normalized a bit and it was able to produce a bit of energy enough to start the engine.

After all the investigations (that resulted in nothing) I have learned this (maybe I am wrong with some of these items but that's how I see it):

- BMW with all intelligent systems controlled by the software had made a big mistake - they forgot that all the drivers are different and it is the car that is supposed to serve the driver, not another way around. So, if for a couple of months my life consists of frequent short trips - that's the reality. Hondas, Toyotas and 10-year-old Kias survive this, BMW should be able to do it too. A modification of the software either allowing to configure the system OR introducing an adjustment for how aggressive it needs to use the alternator - this is all quite feasible.
- this car indeed needs to be plugged in from time to time to compensate for stupid design of the recharging system
- it seems to be that the "Advanced Charging System" (original charger from BMW) cannot really charge 105-amp AGM battery. It charges it to certain level but not more than that. I am going to get CTEK US 4.3 to see if it makes a difference.
- BMW would refuse to change the battery IF they see that you are "poor driver profile", even if the battery is really dead. Well, in my case it was not necessary, but if my battery was found to be dead I would not get a replacement one for free for almost new car. I was told that they had new BMW owners coming in the beginning of first winter with dead batteries - and paying for their replacement. Looks like sometimes you need a lawyer, not a service technician But I was also told that they look 20 days back to determine if you are "bad profile". Conclusion: if you see that your battery is dying, take more longer trips for 20 days
- the supervisor explained me how to properly manage the battery voltage. He told me to open the hood, then lock the car, wait for at least 5 minutes (most of the systems go to sleep), then measure. It does make a difference. I see the numbers like 12.6..12.7V now. And he also pointed me to batteryfaq.org where they have a table that shows the battery voltage for AGMs for different temperatures. While this is not a reliable indicator of the battery capacity, it does give an idea about its health. At least now my numbers do look a bit more optimistic
- the mystery about ASS that may stop the engine even after a short trip when it is -4C outside - I was told that it is the battery temperature that is taken into account, not the outdoor temperature shown on the dashboard. Does it makes sense or not, at least it explains the mystery.
- now I see that idling this car is useless and may be even worse than shutting it down, at least as long as the engine is warm
- for cold nights outside a charger seems to be a must. These batteries, like others, do not like the cold. But when the car is started in the morning they are more stressed than the batteries of other cars because of BMW's [stupid ] design


So, now I am measuring the battery voltage trying to understand how often do I really need to plug it to keep it in good shape and enjoy the car without the risk of being stuck somewhere. Hopefully I will find a proper pattern that balances the inconvenience and reliability.
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  #38  
Old 01-13-2014, 07:46 PM
poker838 poker838 is offline
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Quote:
Originally Posted by ngrigoriev View Post
In last couple of weeks I have learned quite a bit about this car's electrical system. And I had a chat with BMW service supervisor who explained me some details to complete the picture.

The problem we had with the car being unable to start on a cold morning after a short trip has not reoccurred (so far) BUT I have found two more people among the friends and colleagues who had _exactly_ the same issue and one more who was just unable to start the car on a cold morning. Lucky guy, he could at least stay warm

Officially the dealer is unable (or not willing) to explain what happened. To be fair, they do not know for sure, they admit it. When the car got to the dealership they have measured the battery being at 82% (!) and the "startability" factor calculated by the car was at 38%.

My current theory is that because of the STUPID (yes, I believe this is stupid if it results in such a problem) design this car was, essentially, running off the battery during the most of the short trip on the cold morning. And, since all heating stuff was on (the driver wanted to avoid freezing! ) the battery drained like hell. Again, due to STUPID alternator delay logic and because the RBS that is not active until it warms up, this short trip has caused an excessive drain on the battery. And the alternator has started to produce some electricity only when my wife was actually approaching the parking. So, the car was stopped, locked, the battery was continuing to drain (it takes 5 minutes before most of the stuff goes to sleep). So, after few minutes the battery was nearly dead after such a shock.

Also, since it is all about chemistry, after about one hour the battery has somehow normalized a bit and it was able to produce a bit of energy enough to start the engine.

After all the investigations (that resulted in nothing) I have learned this (maybe I am wrong with some of these items but that's how I see it):

- BMW with all intelligent systems controlled by the software had made a big mistake - they forgot that all the drivers are different and it is the car that is supposed to serve the driver, not another way around. So, if for a couple of months my life consists of frequent short trips - that's the reality. Hondas, Toyotas and 10-year-old Kias survive this, BMW should be able to do it too. A modification of the software either allowing to configure the system OR introducing an adjustment for how aggressive it needs to use the alternator - this is all quite feasible.
- this car indeed needs to be plugged in from time to time to compensate for stupid design of the recharging system
- it seems to be that the "Advanced Charging System" (original charger from BMW) cannot really charge 105-amp AGM battery. It charges it to certain level but not more than that. I am going to get CTEK US 4.3 to see if it makes a difference.
- BMW would refuse to change the battery IF they see that you are "poor driver profile", even if the battery is really dead. Well, in my case it was not necessary, but if my battery was found to be dead I would not get a replacement one for free for almost new car. I was told that they had new BMW owners coming in the beginning of first winter with dead batteries - and paying for their replacement. Looks like sometimes you need a lawyer, not a service technician But I was also told that they look 20 days back to determine if you are "bad profile". Conclusion: if you see that your battery is dying, take more longer trips for 20 days
- the supervisor explained me how to properly manage the battery voltage. He told me to open the hood, then lock the car, wait for at least 5 minutes (most of the systems go to sleep), then measure. It does make a difference. I see the numbers like 12.6..12.7V now. And he also pointed me to batteryfaq.org where they have a table that shows the battery voltage for AGMs for different temperatures. While this is not a reliable indicator of the battery capacity, it does give an idea about its health. At least now my numbers do look a bit more optimistic
- the mystery about ASS that may stop the engine even after a short trip when it is -4C outside - I was told that it is the battery temperature that is taken into account, not the outdoor temperature shown on the dashboard. Does it makes sense or not, at least it explains the mystery.
- now I see that idling this car is useless and may be even worse than shutting it down, at least as long as the engine is warm
- for cold nights outside a charger seems to be a must. These batteries, like others, do not like the cold. But when the car is started in the morning they are more stressed than the batteries of other cars because of BMW's [stupid ] design


So, now I am measuring the battery voltage trying to understand how often do I really need to plug it to keep it in good shape and enjoy the car without the risk of being stuck somewhere. Hopefully I will find a proper pattern that balances the inconvenience and reliability.
thank you for providing your insights! I noticed my X3 shutting down more now given that the temperatures have risen a bit.. but during the extreme cold during the Christmas holidays it hardly shut down at all, except when coming off an off ramp after a long highway romp.

Question I have is, does the alternator run and charge the battery when the engine is running, or does it only charge on over-runs (off throttle / deceleration)? ie., I hope that the BMW is charging itself while idling at stops since it's running to produce heat anyway.

Will disabling ASS solve the charge issues?
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  #39  
Old 01-13-2014, 08:09 PM
02420X3 02420X3 is offline
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Quote:
Originally Posted by poker838 View Post
Question I have is, does the alternator run and charge the battery when the engine is running, or does it only charge on over-runs (off throttle / deceleration)? ie., I hope that the BMW is charging itself while idling at stops since it's running to produce heat anyway.
I have an '11, which was built before ASS. I usually run a voltage monitor in the center console socket. I made note of some voltage readings just about a year ago. I can't say whether or not the alternator is sending power to the battery, but it is definitely providing power to the electrical system. Here's what I saw:

The alternator pretty much supplies power all of the time, just at different levels. Here's a quick list of voltages from last January. OAT was a balmy 7F, -14C. My X3 lives outside, so the battery had a nice overnight chill on it.

Locked - Battery monitor display dark, as the 12V receptacle powered down 5-15min after the car was locked for the night.
Unlock and wakeup - 11.78V
Start - 10.45V
Cold Idle - 14.63V
Heated Seats and Steering Wheel on - 14.53V
Driving, side streets 14.4V - 14.6V
Red Light, 14.50V - 14.63V
Driving, state highway, 45MPH limit - 14.2V - 14.62V
Red Light, 14.75V
Interstate highway, 65MPH limit - 14.6's
Red Light, 14.6V - 14.7V
Parking lot, engine running in Park - 14.79V - 14.81V

The voltage appears to be slightly higher when I'm decelerating and into the blue Efficient Dynamics section of the mileage display, but the X3 alternator is definitely supplying power to the bus all of the time.
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  #40  
Old 01-13-2014, 09:00 PM
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AzNMpower32 AzNMpower32 is offline
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Modern BMWs since the new MOST-bus system was introduced back mid 2000s really, really don't like short trips in cold weather. The alternator charges at different voltages based on a myriad of factors, but heavy electronics usage in cold weather (defroster, seat heating, etc...) will quickly drain the battery. But I think I said this many posts ago....."I told ya so...."

For the record, my 10-year old X3 started the very first time, even though the battery is 2,5years old and it was -21C overnight last week.
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  #41  
Old 01-14-2014, 09:13 AM
ngrigoriev ngrigoriev is offline
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Quote:
Originally Posted by poker838 View Post

Question I have is, does the alternator run and charge the battery when the engine is running, or does it only charge on over-runs (off throttle / deceleration)?
My current understanding is that it cycles according to the demand. The rest is a mystery. Most likely this is in the software so it may be complicated (and somewhat stupid also at the same time ). Also I think when it is about the deceleration it is really RBS system, which engages the alternator when decelerating.

Quote:
ie., I hope that the BMW is charging itself while idling at stops since it's running to produce heat anyway.
According to what I have learned it is not true. Idling or not, it seems to be irrelevant - the alternator is engaged when it is needed, not when there is a good chance to engage it Most likely they did it to make the acceleration better? Also, idling is somewhat contradicting ASS idea. I.e. they want to stop the engine when possible, not to idle. With this approach idling would be considered something less frequent and nor desirable, right?

Quote:
Will disabling ASS solve the charge issues?
Apparently not at all, it will make it worse as you will be draining the electricity for heating/lamps/etc.

Last edited by ngrigoriev; 01-15-2014 at 11:45 AM.
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  #42  
Old 01-15-2014, 11:51 AM
ngrigoriev ngrigoriev is offline
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Interesting development...Received an email from the BMW service this morning. Apparently they have found a couple of other poor X3 owners with similar problems. And they did more investigations and found a faulty "power distribution box". The manager said that the faulty relays in that box cause problems similar to what I had. They have ordered the new box, backordered, 2 weeks ETA...So I think I will keep charging the car more aggressively until I get this box replaced and then we'll see.

Glad to see they actually do continue investigating the problem even after the car is out of the garage and do follow-ups.
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  #43  
Old 01-15-2014, 12:58 PM
RhoXS RhoXS is offline
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... this car was, essentially, running off the battery during the most of the short trip on the cold morning.
I do not believe that is the case at all even though BMW seems to indicate that might be the case.

Without any energy input from the alternator and no load on the battery, the voltage will be about 12.6 volts (the open circuit terminal voltage of a lead acid battery). With no energy input from the alternator the voltage will actually be less than 12.6 volts because there is a finite load on the battery and due to the battery's internal resistance the terminal voltage will drop with increasing load.

The voltage can only exceed 12.6 volts when energy is being put into the battery by a charger.

I noticed on my X3, the battery terminal voltage typically is about 13.6 volts or so when the engine is running. 13.6 volts could not be achieved without some consequential energy input from a charging device such as an alternator. 13.6 volts also roughly corresponds to a charging voltage equivalent to about an 80% charge.

The voltage does pop up to 14.7 volts or so when coasting down hill etc. That voltage is what corresponds to a 100% charge.

In other words, from the voltages I observed, the alternator is ALWAYS mainatining the battery at a minimum of an 80% charge. It is not only maintaing the battery charged at this level it is also providing for the entire car electrical load. If the alternator was not also proving for 100% of the car electrical load the battery would be providing the difference, no energy would be going into the battery, and the voltage would drop below 12.6 volts.

In my opinion the dealers do not understand this system any better than anyone else does so they say what ever sounds reasonable when they don't how to or don't want to fix something and what they say is mosly BS. Very few people are in a position to challange them so the confusion continues.

Last edited by RhoXS; 01-15-2014 at 01:01 PM.
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  #44  
Old 01-15-2014, 01:50 PM
Coder Coder is offline
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BMW Power Management Manual

Attached is a BMW Power Management document. I'm not sure how current this is, it refers to F0x vehicles so maybe not valid for those with the AGM batteries, but it does give some clues on the BMW power management approach. Doesn't solve the cold weather issue but shows how complex the system is and what some of the issues are.
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File Type: pdf 03_Power Management.pdf (1.07 MB, 131 views)
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  #45  
Old 01-15-2014, 04:37 PM
vptrails vptrails is offline
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I have a 2011 X3 35i. I believe the 35i alternator generates more charging amperage that the 28i does from the product brochure I have. However, I drive relatively short trips (5 miles or so each way) and I find that if I speed up and let the vehicle coast which keeps the blue charge bar displayed on the instrument cluster that the battery gets a chance to recharge itself on short trips. I haven't had to use a battery charger yet (knock on wood).

More coasting and longer slowdowns (i.e. not stopping short all the time) enable the charger to do its job, especially in ultra cold climates. I see drivers who are either always constantly accelerating and stopping on the brake when they drive. One of the first things I think of (besides the obvious - "knucklehead") is that if they were driving a BMW, they would probably have trouble with their batteries.

Then again, at -24C, that kind of temperature can present problems if your car is constantly parked outside all the time and is not driven long distances. Hope this helps.

P.S. if you don't have navigation, you won't know when your battery is being charged as you don't have the extended instrument display to gauge when its charging.
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  #46  
Old 01-15-2014, 06:26 PM
ngrigoriev ngrigoriev is offline
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Then again, at -24C, that kind of temperature can present problems if your car is constantly parked outside all the time and is not driven long distances.
I would believe it if I did not have two other cars before this X3, one used and old and one new. The climate was the same, the commute distance and driving patters were the same, the desire to heat the car, defrost the window and heat the bottom part of the driver was the same. Except that the second (new) car had remote start that I always used when it was cold outside to let it warm up for about 4-5 minutes. Maybe that was the key difference, extra few minutes of idling + dumb alternator. No such luxury with X3.

Quote:
P.S. if you don't have navigation, you won't know when your battery is being charged as you don't have the extended instrument display to gauge when its charging.
I do coast quite often, typically when I see the traffic light just turning yellow and then red at next intersection, or for a little while when approaching the turn if the traffic conditions permit. I do see the blue indicator on the dashboard. But in total, I think, the "coasting" time still represents less than 1% of the total commute time so I would not consider it very important.
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  #47  
Old 01-16-2014, 10:21 AM
RhoXS RhoXS is offline
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Originally Posted by Coder View Post
Attached is a BMW Power Management document. I'm not sure how current this is, it refers to F0x vehicles so maybe not valid for those with the AGM batteries, but it does give some clues on the BMW power management approach. Doesn't solve the cold weather issue but shows how complex the system is and what some of the issues are.
Thank you very much for making that document available. It is excellent.

P40 discusses charging voltage as a function of temperature. In addition, the following is a quote from the top of page 41:

"Since the current absorbed by a cold battery is lower, the voltage for charging must be higher than for a warm battery."

This behavior is exactly what I observed on my X3. When the temperature was mild, the charging voltage, as I indicated in a post above, never dropped below 13.6 volts or so and, in fact, remained very constant at this voltage except when coasting downhill and then the voltage would pop up to about 14.6 volts or so.

According to the quote above and the voltage temperature chart on page 40, the voltage should run much higher once the temperature, as sensed by the IBS on the negative battery terminal, sees lower temperatures. This is almost exactly what I am now seeing in cold weather except the increase in voltage on the X3 with the AGP batteries seems even more aggressive. With temperatures now rarely going over 40 F and mostly well less than 30, the voltage is continuously running greater than 14.5 volts.

This again supports what I think is happening. The battery is always, repeat always, being charged to some significant extent and the alternator, in addition to always maintaining the battery charged, is also fully carrying the cars electrical load. It would be impossible for it to be any different with a voltage greater than 12.6 volts. In fact, when the IBS sees cold temperatures, the battery is charged even more aggressively to compensate for the decrease in battery performance when cold.

So, again my point. All this discussion about going to effort to coast so the battery gets charged etc. is just not needed nor consistent with how the system works based on the voltages I observed. I also do not believe a smart company like BMW is going to market a car that requires the driver to manage charging the battery when this has not been necessary since at least the 1930's.

I think what has happened here is BMW has what they think is a great marketing idea selling economy and efficiency. Because they have never really explained how the system works, this overly complex system, with questionable real savings, is not understood, even by the dealers. As a result there seems to be this great misconception that the battery does not get charged unless braking or coasting downhill. I believe that is a bunch of crap and the battery is always being charged to at least an 80% state when driving the car.

Last edited by RhoXS; 01-16-2014 at 10:42 AM.
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  #48  
Old 01-16-2014, 12:04 PM
Coder Coder is offline
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Rho, concur ... unless there are problems in the system. It's possible that, in extended cold weather as described in this thread, one or some of the components don't get the job done. Given the number of complaints, it seems like there might be a design flaw or weak component in there somewhere. I know that BMW does extensive cold weather testing so it's hard to fathom what is going wrong. Probably beyond the ken of most dealers and will have to be solved by the BMW engineers.
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Old 01-16-2014, 05:16 PM
ngrigoriev ngrigoriev is offline
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Probably beyond the ken of most dealers and will have to be solved by the BMW engineers.
As I said yesterday, looks like they have found a possible problem. When they get the part and I get it replaced on my car I will post the description from the report. And I will certainly try to ask the guys there about the nature of the problem they have found, just for my curiosity.
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Old 01-17-2014, 05:43 AM
RhoXS RhoXS is offline
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Originally Posted by Coder View Post
... Given the number of complaints, it seems like there might be a design flaw or weak component in there somewhere. I know that BMW does extensive cold weather testing so it's hard to fathom what is going wrong. Probably beyond the ken of most dealers and will have to be solved by the BMW engineers.
I would suggest anyone with a concern about the proper functioning of the system buy one of the relatively very inexpensive voltmeters that plug into a cigarette lighter socket.

I verified (albeit not continuously via a long term test) the voltage indication at the console cigarette lighter outlet, between the cup holders, exactly matches the battery terminal voltage. I thought this was necessary to verify because there could be a DC-DC voltage regulator that maintains 13 or 14 volts no matter what the battery terminal voltage is (at least until the battery is depleted). What I observed was an exact corresponce between the two points.

If the voltage when driving is maintained greater than 13.5 volts or so, the charging system is pumping energy into the battery and problems are then likely to be associated with the battery not taking the charge.

If the voltage when driving is maintained less than 13.5 volts or so (especially less than 13.0 volts) the charging system is not pumping sufficient energy into the battery and problems are then likely to be with the charging system.

When monitoring the voltage I suggest observing the system response when turning on a large load such as the rear window defogger. If the voltage is sitting at say 13.5 volts, and only momentarily jumps a few tenths of a volt but then returns to a steady value where it was previously, the alternator fully picked up the new load and the battery is still being maintatined charged.

If the voltage drops more than a few tenths of a volt or so and does not recover, then there is definetly a problem with the charging system or the total load exceeds the capacity of the alternator which I doubt will be the case.

These observations should help a lot when the dealer tells you that you have a crappy driving profile and that is exactly why I am taking the time to write this post.

From my observations, the system voltage under all conditions (except when coasting or braking) never varies from 13.5 volts or so when the temperatures are mild. In cold weather (under 40?) the voltage remains rock steady about 14.5 volts. I would suggest using these values as a a guidline for what is normal. I had a 2013 X3 loaner during service a short time ago and I regret not having monitored it to see what voltage was maintained although I would bet it would have been exactly what I see in my car.

I hope these posts are not belaboring an issue but I do not like seeing people told by a dealer an electrical system problem is due to a bad driving profile when there is actually a problem. It also bothers me that a lot of people are spending a lot of unnecessary energy trying to manage battery charging when this function works as well as it does on any other vehicle (when nothing is broken) without any intervention by the driver.

Last edited by RhoXS; 01-17-2014 at 10:27 AM.
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