[RhoXS]

Originally Posted by plymjack

I think the issue is with a car that only does short trips (eg less then 10miles each time) in that the battery never gets a good charge.

I assure you that is not the case.

My one way trip to work is 7.5 miles. When starting the car on cold mornings (most mornings now in northern, NY) I immediately push the front windshield defogger button so the fan runs on high, push the rear defogger button, put the drivers seat heater on high, and turn on the steering wheel heater. The headlights are also on. All this accounts for a lot of electrical load and occurs twice a day; going to work at about 0530 and again when going home in late afternoon. Because of all the discussion about this problem I continuously monitor the voltage and it remains rock steady at 14.6 volts or so, even at idle. At this voltage you can take it to the bank the alternator is not only fully supplying the cars entire electrical load but energy is also being charged into the battery. I have never yet had a problem. It was -4 F this morning, the car was cold soaked after sitting outdoors all night for about 12 hours, and the car started without a problem, as it does everyday. This routine occurs 5 days a week, I do almost no other driving except to/from work, and typically the car sits idle from Friday night to Mon morning. The vehicle would not reliably tolerate this routine if the charging system was not up to the task. A smart company like BMW is not going to intentionally design a system that introduces consequential limitations that none of their competition has.

In my opinion the charging system, albeit overly complex, is robust and up to anything asked of it, as long as nothing is broken. I do not believe it is necessary to do anything more than in any other vehicle. If there is a starting problem then something is broken and the dealer needs to fix it. People who report the dealers are telling them they have a poor driving profile are being given a bunch of bad smelling BS from the dealers probably because the dealers don't understand the system and don't know what to fix.

[Phoskins23]

Here in Connecticut the temperature has been in the negative numbers. As expected, I got the "charge battery" indicator after arriving at work. I usually drive 20 miles per day so this is not enough. I finally broke down and bought a battery charger and hooked it up and it indicated my battery was at 27%. I love this car in every other way but this is ridiculous that I have to charge a battery in my $50k car. I bet this is not an issue with a Hyundai. BMW-- are you listening to us on this forum??

[lbjgh]

You might be able to find and abandoned Hyundai for the same price as your charger and it would serve the same purpose.

BMW engineering ... over promise and under deliver... hey the car is great to drive if ya can get it started.

I've had four different warning/error messages about various faults in my car. I'm starting to wonder if the errors are related to software glitches rather than actual faults. Anyway there are a few other premium brands that would not sell a vehicle with this level of QAQC.

Don't get me wrong I love my X3 but it may be better suited for more temperate climes.

Originally Posted by Phoskins23

Here in Connecticut the temperature has been in the negative numbers. As expected, I got the "charge battery" indicator after arriving at work. I usually drive 20 miles per day so this is not enough. I finally broke down and bought a battery charger and hooked it up and it indicated my battery was at 27%. I love this car in every other way but this is ridiculous that I have to charge a battery in my $50k car. I bet this is not an issue with a Hyundai. BMW-- are you listening to us on this forum??

[plymjack]

Originally Posted by RhoXS

I assure you that is not the case.

?
You still don't explain how the battery is fully charged by 7.5 mile drive. - cos it wont be. and each time you are reducing the battery capacity.

Having worked with large (240v batteries) these take over 10 hours to fully charge, yes the initial charge works but to get a full capacity will take more than a 7.5 mile run (occurring on repeated days) .

So no I am not assured, sorry.

[RhoXS]

Originally Posted by plymjack

?
You still don't explain how the battery is fully charged by 7.5 mile drive. - cos it wont be. and each time you are reducing the battery capacity.

It takes a lot less time than most people think to re-charge a car battery after starting a healthy car.

The typical duty of a car battery is to only start a car then be immediately recharged. Any other discharge that results in a seriously depleted battery is just not within the design basis of a car. The alternator provides for the cars electrical load so the battery is never providing consequential energy except when the car is being started. Assuming the car starts immediately, which my X3 does, even in sub zero temperatures, it does not take very long to top the battery off again.

Let me give you an example. My X3 starts easily in 3 seconds (probably about 2 seconds of cranking in very cold temperatures, less than a second in reasonable temperatures). Just guessing but I think it is reasonable to conservatively assume starting current is not more than 400 amps. That accounts for energy equivalent to 1200 amp-seconds. My 7.5 mile trip time varies but it is typically a little longer than 15 minutes and probably approaches 25 minutes on a cold snowy morning with greasy streets. 15 minutes equals 900 seconds. So, over 900 seconds, only 1.4 amps needs to be put into the battery to replace the equivalent energy. That is very easy to do and, in fact, the charging current is actually much higher. Even recognizing that the discharging/charging process is less than 100% efficient, it still does not consequentially change what is required to get the battery back to the desired state of charge. These numbers are all guesses but they are certainly in the ball park.

The X3 is not very different. There is some load when the car is shut down but that load is very small and really does not account for any consequential energy over say a 12 hour period (night when I get home until morning when I leave)or even over a weekend. In addition, the system voltage immediately settles at 14.5 volts or so after starting, even at idle. As I previously said, at this voltage the alternator has to be providing for every bit of the cars electrical demand plus be charging the battery.

The BMW X3 uses an oversize battery and, by design, does not charge it to 100% capacity. Since the battery is oversized, per the BMW brochure, 80% capacity is equivalent to what 100% would be if the car did not have this weird charging system that requires some room to put coasting/braking energy without overcharging it. Nevertheless, 14.5 volts will still return the battery to a high state of charge, albeit not 100%.

[plymjack]

You are not "wrong" in your figures, but I do think there is a accumulative depletion effect to take into account - without a longer more sustained charge the battery will lose capacity over time if it is only having these short charging runs between each "starting " cycle.
Also the additional load from other use needs to be allowed for (eg lights, wipers, A/c, heated seats!, fan etc).

"an oversize battery by design does not charge to 100%" - Is however wrong, if it is not fully charged it will deteriorated over time and this is the part where the long run is need and I think is the problem being highlighted.

I do have experience in battery charging (in submarines not cars) and can assure you the only acceptable state to maintain is 100% charged, anything less is bad for the battery and bad for the car/submarine.

[RhoXS]

Originally Posted by plymjack

You are not "wrong" in your figures, but I do think there is a accumulative depletion effect to take into account - without a longer more sustained charge the battery will lose capacity over time if it is only having these short charging runs between each "starting " cycle.
Also the additional load from other use needs to be allowed for (eg lights, wipers, A/c, heated seats!, fan etc).

"an oversize battery by design does not charge to 100%" - Is however wrong, if it is not fully charged it will deteriorated over time and this is the part where the long run is need and I think is the problem being highlighted.

I do have experience in battery charging (in submarines not cars) and can assure you the only acceptable state to maintain is 100% charged, anything less is bad for the battery and bad for the car/submarine.

What you say is very true for a standard lead acid automotive battery that uses sponge like lead plates to maximize the amount of so called cold cranking amps (more correctly called short circuit current). Two destructive processes take place when one of these batteries is not maintained 100% charged. First, the sulfate deposits deposits on the depleted areas of the plates harden with time and become non-reversable. In other words, the usable plate area (ie capacity) will gradually decrease with time if the sulfate deposits are not removed by charging. Second, when deeply depleted, the sponge type lead plates lose their mechanical strength and literally fall apart. Since a standard automotive battery is intended to do nothing more than start the car then be immediately recharged, this never presents a problem. People do not realize if they inadvertently leave their lights on and deplete the battery so the car does not start, they have permanently damaged it to some extent. The car might be able to be jump started but that battery is now damaged goods. Also, even a few tenths of a volt can make a difference. Lead anitmony batteries are "standard" car batteries. Lead calcium batteries are "maintenance free" car batteries because they do not off gas very much when being charged. A lead calcium battery requires a charging voltage a few tenths of a volt higher than a lead antimony battery for a 100% charge. If a maintenance free battery is installed in a car designed for a lead antimony battery it will eventually fail (my experience is in about a year) because it is never fully charged.

The X3 uses an AGP battery - NOT a standard automotive type lead acid battery. This type of battery uses a radically different construction, has deep discharge qualities, and does tolerate, very well, not being fully topped off. BMW had to do this to leave some room to put the energy recovered from coasting and braking. If a standard battery at a 100% state of charge was used, the battery would be overcharged everytime you coasted downhill or used the brakes. This would cause the production of hydrogen, excessive heat, and a loss of electrolyte.

You stated the "additional load from other use needs to be allowed for (eg lights, wipers, A/c, heated seats!, fan etc". It certainly is. The alternator is rated at 2940 watts. Thats almost 3KW and at 14 volts or so that is over 200 amps. I assure you, even with the all the load hungry stuff we use on a cold day that is more than sufficient to carry the car's electrical load plus put energy into the battery. The proof of this is obvious because there is no way the system voltage can be maintained at 14.5 or so volts if the alternator was not providing for 100% of the load and putting energy into the battery. As soon as the load exceeds the alternators ability the battery has to take up the slack and the battery terminal voltage will immediately drop to something less than 12.6 volts.

[Gouda]

I have been keeping up on all this discussion with interest. Our 11 X3 35i has spent it's entire life in northern Minnesota and Wisconsin. Never have seen any errors of any kind like what has been discussed here. Last weel I was into Motorwerks BMW in the Minneapolis area on a unrelated matter. I discussed this with the SA that has treated us well. Specifically about the need for putting the battery on a trickle charger and avoiding the drivetrain error and lower battery warning. He told me that if I put a trickle charger only when the temp is near or below zero F, I may add a couple years to it's life. He also mentioned that people forget how power hungry these vehicles are and specifically that they have electric power steering. That will take precedence in power management as it should. I can't say if that is all correct but it makes sense to me. Just thought I would offer those comments up.

[HighlandPete]

BMW Wrote:

12 VoltBattery Care
If your X3, X5 or X6 is driven only for short distances of less than 10 miles over a prolonged period of time, without an occasional drive at highway speeds, the engine’s charging system will not maintain the battery. Insufficient use of the vehicle could result in short term starting problems and in the long term could damage the battery.

Says it all, doesn't it.

There is a very high consumer demand on our latest models, and in perfect conditions maybe we can get away with limited use.

RhoXS mentions a 7.5 mile drive, then indicates that it can be 15 - 25 minutes driving according to conditions. That is a bit different to some users 7.5 mile drives. If I drive 7.5 miles from home, that would be 10 minutes maximum, see how just one factor of user profile soon changes the actual charge time. Then put in all the other variables, a simple thing like how much the EPS is used towards full lock will have a major bearing on how the power management copes with consumer load from cold.

Vehicle logs the wake-up and sleep mode history, so if there is nothing wrong with battery drain levels, interrogation will soon show if "user driving profile" is a major contributor to a battery losing charge capacity.

HighlandPete

[colson79]

My 2012 X3 35i let me down for the first time yesterday. It was about -19 F yesterday morning and the X3 was in the garage which was about 30 F. X3 started right up, with no errors or warnings. I drove to work, 25 miles mostly highway and takes me about 30 minutes. Parked the X3 turned it off and got a low battery warning. Didn't think to much of it because I got this error once before. I had to run some errands for lunch so I left about 4 hours later and the X3 started up again but I got a increased battery discharge warning.

I drove about 15 minutes to the store, shut off the X3 ran inside for about 10 minutes. Came back out and the X3 wouldn't start, made a clicking noise and gave me a charge battery warning. Luckily I always carry jumper cables in the car and I was able to get a jump from someone.

I think the charging system in this car really sucks, get rid of that stupid efficiency dynamics stuff, I'll take the 1 mpg penalty.

I put it on the charger when I got home, but It was -21 F this morning so I drove my old 2006 Mazda 3 because I was afraid of getting stranded in my $50,000 BMW. Really sad.

[plymjack]

It is a combination of low temperature, high energy load and insufficient charging time - due to short runs.

Its so obvious - having maintain a battery system 10000 times bigger the factors are still the same.

It may well be a different construction but the basics are still the same. Anyone who thinks the battery is fully re-charged after a 10 minute run is just ignoring the obvious.

[colson79]

Originally Posted by plymjack

It is a combination of low temperature, high energy load and insufficient charging time - due to short runs.

Its so obvious - having maintain a battery system 10000 times bigger the factors are still the same.

It may well be a different construction but the basics are still the same. Anyone who thinks the battery is fully re-charged after a 10 minute run is just ignoring the obvious.

But I have a 25 mile commute every day, so a total of 50 miles a day, and my X3 still left me stranded with a low battery this week. An hour a day should be enough to charge my battery no matter how dam cold it is outside.

[plymjack]

I cant say for sure that such a run will fully charge the battery each time, so you could be slowly depleting it if your not given it a good "long" trip.

[am36]

Just adding my experience....I have a 2.0D 2013. A few weeks ago, the low battery warning came up on the display. Car had been sat about 10 days, so thought nothing of it. Car started okay.

Started a 90 mile round trip daily commuting period, during which I had 2 low battery warnings. Contacted Dealer who had a quick look and determined it to be an intermittent fault with the driver's door microswitch unit ("the car thinks its unlocked, thus the electronics are active, draining the battery"). Left car with dealer and they replaced the switch assembly.

Went to pick the car up from the Dealer, they had checked the electrical system out after replacing the switch and found an additional 400mA drain on the battery. The technician believed it to be the main junction box, this has also been replaced. Report from dealers suggest this has cured the problem.

Had a nice 4 series loaner so can't complain.

[RhoXS]

Originally Posted by plymjack

I cant say for sure that such a run will fully charge the battery each time, so you could be slowly depleting it if your not given it a good "long" trip.

I have commented extensively on this before so I will not say much more now other than:

The electrical system in the X3 is very well designed, at least with respect to what it is capable of doing when everything is working properly. It will charge the battery even at idle on a subzero day. An alternator, with a properly designed control system, does not have to be driven at high RPM to get a substantial amount of energy out of it, contrary to what many people think. Also, if you look at the amount of energy taken out of the battery to start the car (a few hundred amps at 12 Volts for just a few seconds) to how long it takes to replace this energy, even at dismal efficiencies, it does not take very long. Therefore, when the dealer says your dead battery problem is due to a poor driving profile with short trips, it is a bunch of crap. The X3's electrical system is easily up to the task with a 3KW alternator and very well designed electronic controls.

From my own experience, for the entire past miserable winter, in Oswego, NY, I only drove 7.5 miles to work in the morning and then home at night. It gets very little other mileage. I do not hesitate to electrically load it up on cold mornings with the steering wheel heater, driver's seat heater, rear window heater, headlights, foglights, and fan on max to deice the windshield. Not once has the voltage dropped below 14.6 volts or so, even at idle, meaning there has to be energy going into the battery charging it including carrying the existing electrical load. I never had a single issue starting the car. The same, BTW, was true for my wussy Lexus RX350 the previous 2012-2013 winter.

What I am trying to say is:
If you have an issue with a dead battery it is because something is not working correctly. It is a repair issue. It is not by any means a driving profile issue or a system design issue (except maybe a reliability problem).

[PX3]

The wife went to start the X3 this morning only to find it wouldn't start due to a discharge battery warning! She is now waiting for the BMW Assist guy to turn up.

I'll keep you informed of the outcome.

[plymjack]

We use our X3 mostly at weekend and mostly for longer trips. If I use it after it has not had a longer (over 20miles) run then I always notice that the auto stop/start does not operate initially, can be up to half an hour driving before it then functions. This I assume is because the battery is charging having been drained over time. This is exactly what I would expect so is not a concern but logically if the car was left for longer it may well end up with a flat battery (my guess is around 6 weeks) - and that's not because anything is broke it only needs a charge rather than a repair.

[PX3]

Originally Posted by Petex3

The wife went to start the X3 this morning only to find it wouldn't start due to a discharge battery warning! She is now waiting for the BMW Assist guy to turn up.

I'll keep you informed of the outcome.

Ok, the battery has been recharged and will be replaced by BMW on Wed free of charge.
The car gets two 37 mile runs a week as well as short journeys every day, so maybe it's one of those things.

[plymjack]

Originally Posted by Petex3

Ok, the battery has been recharged and will be replaced by BMW on Wed free of charge.
The car gets two 37 mile runs a week as well as short journeys every day, so maybe it's one of those things.

Without a long run then such use is going to shorten the life of the battery. But good to get a replacement.

[Pitiful Old Man]

Our 2011 (with all the options) sits in the garage for 3-5 days at a time. Normal trips are maybe 10-15 miles, mostly 30 - 40 mph. Never any problems. If you are experiencing problems, check the charging system and the battery. Either could be at fault. You might try calling the BMW Genius folk at 1.844.4GENIUS (443-6487). Your dealer support seems pretty weak.

[PX3]

Originally Posted by Pitiful Old Man

Our 2011 (with all the options) sits in the garage for 3-5 days at a time. Normal trips are maybe 10-15 miles, mostly 30 - 40 mph. Never any problems. If you are experiencing problems, check the charging system and the battery. Either could be at fault. You might try calling the BMW Genius folk at 1.844.4GENIUS (443-6487). Your dealer support seems pretty weak.

I plan to see how the new battery goes first as I've had no issues with the car since owning it for just over a year now. I certainly wouldn't jump to any other conclusion that it may be something more serious as it could well be a genuine issue with the battery and being that's an easy change to do, I'm quite pleased they're replacing it. At least if the issue shows up again in another year, I can request some further checks as the battery would only be a year old.

Also this was BMW Assist that dealt with the work, not my local dealer. Plus I certainly wouldn't expect a BMW Genius to know what the issue is, as over here in the UK they are primarily available to the dealers to assist in vehicle technology, not mechanics.

[cooldude00]

hmm.. looks like it's my turn... Wife tried to start the 2011 X3 this morning and had a "battery discharging whilst stationary" warning. Tried to jump start but wasn't succeeed so now waiting for BMW assist to turn up...

normally short weekday journeys mixed with longer journeys during weekends - 26k miles over 34 months and just did a trip to Gatwick (50 miles each way) earlier in the week as well so a little baffling.

brilliant timing as we're flying off on hols on Sat...