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Discussion Starter #1
2013 x5 48,000mls started idling rough periodically. Sometimes at a stop light it will stall, the mpg meter is erratic, sometimes the rpms run higher. The check engine light comes on then later that day goes off. I usually run the AC and Max AC all the time in the summer. It seems to run a little better when it is off.

This past winter we did get a low charge warning (when it was really cold - temps) and had all kinds of weird errors i.e car not level etc. once the temps changed everything was fine.

But everything was fine until a week ago. I thought I got bad fuel but we have since used chevron Techtron and have ran the entire tank through.

We do have an appt for our mechanic but hoping to see what you all think.
 

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Nuclear engineer
02/2012 X5 35d M57Y CPO 100K miles NOKIAN WR G3 20K miles
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I smart charge my battery weekly, it usually takes about 5 AH.
 

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Do we need to charge the battery every week to keep the battery in good shape? I do them once a month but not regularly.. Still the stock battery since 10/2011..
 

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Resident Curmudgeon
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2013 x5 48,000mls started idling rough periodically. Sometimes at a stop light it will stall, the mpg meter is erratic, sometimes the rpms run higher. The check engine light comes on then later that day goes off. I usually run the AC and Max AC all the time in the summer. It seems to run a little better when it is off.

This past winter we did get a low charge warning (when it was really cold - temps) and had all kinds of weird errors i.e car not level etc. once the temps changed everything was fine.

But everything was fine until a week ago. I thought I got bad fuel but we have since used chevron Techtron and have ran the entire tank through.

We do have an appt for our mechanic but hoping to see what you all think.
"What we think?" I think Id like to know what PRECISELY happned 'a week ago'

The rest of your post seems to be a historical review of issues sometime in the distant and mid term past...leading up to a week ago.

I also caution you that having ignored CELs over the past, you will likely have MANY codes to sort through. You (or your mechanic) needs to read and write down codes, but they reset the codes and see which specific ones return.

I will add that battery issues and low charge CAN cause issues like you describe- BUT you may have both a battery issue and something else, and ignoring this over the year(s) can complicate diagnosis...
 

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Nuclear engineer
02/2012 X5 35d M57Y CPO 100K miles NOKIAN WR G3 20K miles
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Since 2008 all OE BMW batteries are starved electrolyte AGM-VRLA. That means that they are built with the minimum possible electrolyte absorbed into glass mats pressed tightly as possible (so tightly that the cases bulge sometimes) between the lead plates in a sealed gas tight case with a gas pressure relief valve that vents to the atmosphere.

One ampere-hour of overcharge electrolyzes 0.335 grams of water into ~400 cc of mixed hydrogen and oxygen gas that is vented when ~< 3 psi has accumulated. The AGM battery is instantly marginally damaged by the least overcharge, and BMW prevents overcharge by NEVER EVER fully charging its battery. BMW batteries are chronically undercharged.

An AGM battery expected life time is about eight years until internal corrosion reduces the AH capacity to End of Life criterion of 80%.

An AGM battery cycle life is correlated with its average State of Charge, average SoC 70% correlates with 1,000 equivalent full capacity discharge-charge cycles. Think of it as through-put. An AGM never significantly discharged, always trickle charging at the self-discharge rate, will last eight years.

An AGM must not be rapid charged or charged at more than 14.8 VDC. Rapid charging heats the battery electrolyte and causes excessive gassing even at otherwise nominal normal charging voltages - called Temperature-Voltage-Gassing. An AGM is overcharged to reach 14.8 VDC.

There are four on point BMW technical documents in LPCapital's G00gle Drive site. I refer also to BatteryUniversity.com and BatteryFAQ.org
 

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Discussion Starter #7
The only thing that happened "a week ago" was the refueling. No major events. Drove to gas station. Then all of this started.
 

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Nuclear engineer
02/2012 X5 35d M57Y CPO 100K miles NOKIAN WR G3 20K miles
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[ ... ] I usually run the AC and Max AC all the time in the summer.[ ... ]
Why?

MAX is intended to override all AUTO programming by setting cabin temperature set point to 60F, shutting all flappers except those that direct air to front vents and blower to maximum. It defeats a number of protections.

The AC is always fully loaded by default, throttling only for power demand control at engine IDLE and WOT, and to prevent evaporator icing. Cabin temperature control is by left and right engine cooling (hot) water radiators that are individually controlled by computer controlled throttle valves - the 'dual valve assembly'.

Better to return all of your AC AUTO and MAX settings to default and adjust the programming of the three AUTO programs as you desire. There may even be an iDrive 'return to default' function.

The BMW AC is quite mechanically conventional, but it's controls and features are highly integrated and complex. Read your owner's manual closely.
 

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Ive reread your post.

near as I can tell the first sentence is what is currently happening...then you start talking about historical issues....coirrect?

So right now the ONLY symptom is:

2013 x5 48,000mls started idling rough periodically. Sometimes at a stop light it will stall, the mpg meter is erratic, sometimes the rpms run higher. The check engine light comes on then later that day goes off.
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What codes show up when you use a BMW code reader? Even with the CEL off, the codes will remain stored.

ANYTHING other than reading codes is pissing away everyones time,

One other question, 2013 with 48k...no warranty??? If you are JUST out of warranty, a BMW dealer CAN authorie 'good will' repairs....

Finally, I am not in the battery camp on this one, nor do I think your use of AC has anything to do with it....
 
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