[bimmer97]

Hi,
First time using a forum, but have read through many throughout the years!
I'm in need of some major help/ advice.

My 2011 335i xDrive e90 has just reached 80,000. It was due for an oil change and a new battery. This is the first time my BMW is out of regular and extended warranty. So I did some research and decided yesterday to take it to a local shop. They work with BMW quite often and assured me that all products/parts are OEM.

Got the car back and everything was perfect as it was before I took it to the shop... Today, as I was driving the yellow "service engine soon" light came on. I took it right back to shop. They ran a diagnostic test and it came up with a couple codes, but it said NONE were currently present. They cleared all the codes. After driving for ten minutes they came on again!! I called and was frustrated as my car was perfectly find before coming to the shop, but now the engine light keeps coming on.

The guy told me "the faults could be coming on now and NOT before due to having a weak battery... and when the new battery was installed the car NOW has enough power to talk to each other and display the faults"??? Idk but that sounds like total BS but I could be wrong, therefore. am posting on this forum!!!

Maybe the engine needs to be reprogrammed and registered again??? It wasn't properly installed? Im going back tomorrow. Ill list the codes bellow...

1.1 3876-Power management: central undervoltage
1.2 3392 Engine switch-off time, plausibility; Time too short in correlation to engine-coolant
2.55c3- VTG Transfer Case AWD limp-home control activated. NO DSC specified nominal torque

3. ABD DSC (Bosch) Dynamic Stability Control 6Ec4- DSC: Steering angle sensor, adjustment

*None of these codes were present at the time it was scanned
****
Thank you for any help and advise before hand

[///Mposter]

Did they program the battery type ? lead acid? or ? AGM? and the amp hours? If it was a BMW battery and the exact same part then only a registering is required where the new battery date is entered and the alternator then charges less because it?s a new battery.

If they didn?t at minimum register it, the alternator would over charge the battery and either cause a fire or cut the life of it in half.

[bimmer97]

Originally Posted by ///Mposter

Did they program the battery type ? lead acid? or ? AGM? and the amp hours? If it was a BMW battery and the exact same part then only a registering is required where the new battery date is entered and the alternator then charges less because it?s a new battery.

If they didn?t at minimum register it, the alternator would over charge the battery and either cause a fire or cut the life of it in half.

Yes, it's a different battery brand but it is similar specs as the original battery. They said they registered and programmed the battery. My assumption is that it wasn't done properly, therefore, needs to be re programmed and registered again??

[arkie6]

I've replaced my battery with a different brand but essentially like-for-like battery over a year ago, didn't register or code anything, and didn't get any dash lights. I did hook up a spare battery to the battery cables in the engine bay when I did the battery swap so the car never lost voltage. Battery charges just fine at 14.4 to 14.6 volts which is perfect for a lead-acid car battery. Where do people get this info that your battery will overcharge, catch on fire, or have reduced life if you don't register it?

[fmc000]

Originally Posted by arkie6

Where do people get this info that your battery will overcharge, catch on fire, or have reduced life if you don't register it?

From BMW, let's assume they know their cars. BTW, I just had my battery replaced by BMW with an identical model and they registered and coded the new battery, as expected.

[arkie6]

Originally Posted by fmc000

From BMW, let's assume they know their cars. BTW, I just had my battery replaced by BMW with an identical model and they registered and coded the new battery, as expected.

I have no doubt BMW knows their cars. They also have a desire to make money. It cost me ~$110 for a new battery (with free 3 year replacement and prorated to 5 year warranty) and ~15 minutes to install it. BMW charges ~4 times that much to replace the battery.

I've read that BMW's battery charging scheme is done to extend the life of he battery. I'm not sure that I buy that. BMW needs the battery to last 3 years to get through the warranty period so they don't have to replace it on their $. After 3 years, the quicker it fails the more $ BMW makes.

I work with large lead-acid batteries (125 VDC banks) in a nuclear power station. These batteries typically last ~20 years. We never alter the charge rate (constant voltage charging) on the batteries except following a discharge test done every 18 months where we do a high rate equalize charge to restore the battery to full capacity. We also have a large population of 12V AGM batteries similar to auto batteries throughout the plant. They are replaced approximately every 5 years and the charge rate on these batteries is constant throughout the life of the battery.

I can see the benefit of altering the charging voltage (via coding I presume) if you are switching from a conventional vented lead-acid battery to a sealed valve-regulated lead-acid (VLRA) absorbed glass mat (AGM) battery. AGM batteries are much more sensitive to overcharging and prone to dryout and possible thermal runaway if overcharged. Standard vented lead-acid batteries are much more forgiving of charging voltage.

[arkie6]

I suspect that if you register the battery every year in the DME regardless if the battery is replaced, you would get more life out of the battery since it appears that BMW charges a new battery at a lower rate than an old battery. Lower charging rate = longer battery life as long as the battery is maintained in a fully charged state. Higher charging rates = accelerated battery aging. Contrary to what I have read on the forums, older batteries do not need to be charged at a higher rate than new batteries even though it appears that is what BMW does. All of my other non-BMW vehicles I have owned typically get 5 to 7 years or more out of the batteries before needing replacement and they do not alter the battery charge rate regardless of battery type or age. High temperature is the main driver of accelerated battery aging and with BMW placing the battery in the trunk rather than the hot engine bay, 5 to 7 years out of a battery should be no problem. Maybe this is BMW's way of failing the battery after 3 years is up. So, now that I think about it, maybe there is a benefit to registering the battery so the car always thinks the battery is within the 3 year warranty period regardless of the battery age and keeps the charging voltage at the lower end of the range.