[ewalk]

2014 320i xDrive - it has been extremely cold lately (-30 C) and my electric steering is cutting out. Usually occurs when there is a heavy load on the battery/charging system (heated seats on, defroster on, heated steering wheel on, defrost fan full blast) and normally once the car has been restarted a couple of times over a 10 minute period. Originally feared it was the rack but once the car is stopped, it operates normally after an hour or so. Only occurs in stop/start city driving and not on the highway. Getting the dreaded "Battery not charging at idle, electrical functions stopped" message (but get that every winter since purchased 7 years ago).

So my question is this: will a extremely discharged battery cause not only non-essential electrical items to stop but also affect the power steering? Battery is the original battery since new (confirmed with Schwaben code unit) and the car has 160,000 km. I'm going to change out the battery regardless, after 11 years she deserves a new battery! I haven't had the battery load tested at all yet.

Has anything like this occured to anyone else? I am hoping that changing out the battery will cure this and will check back in to advise if this cures the problem, but curious if this has happened to anyone else.

[Billfitz]

Cold could affect the steering. Even with the battery at a full charge extreme cold will cause the dash warning and can result in the power management system reducing power to some systems. The age of the battery might also cause the power management system to be more conservative than it should be. At 11 years and 160,000 km I'd say you got your money's worth out of the original battery.

[ewalk]

That's kind of what I suspect. And yes, 11 years for a battery is extraordinary and I realize we're living on borrowed time.

The dash warning is interesting. The first time it occurred I called the dealership. They said it is normal and it is a design feature to keep the alternator form running needlessly in order to increase gas mileage. His suggestion? Take the car out for a good long run on the highway periodically to charge up the battery!

That makes a lot of sense (please note sarcasm).

[Wires]

He's not wrong. You need longer run times at constant revs for the charging system to be effective. Short trips are bad for battery state of charge.

The alternative is to trickle charge it to top it off. In your case, I suspect your battery capacity isn't really up to par at that age.

[Billfitz]

He is wrong. I got my first dash warning a few weeks back, when the temperatures dropped well below 0F. Said warning came up when I turned the car off after driving an hour at highway speeds, while my monitor read 12.5 volts. I got my second warning later that day, also after driving an hour at highway speed, and the third after driving another 45 minutes at highway speed. A few days later I got no warning after driving ten minutes in town. The temperature had risen.

[ewalk]

Originally Posted by Wires

He's not wrong. You need longer run times at constant revs for the charging system to be effective. Short trips are bad for battery state of charge.

The alternative is to trickle charge it to top it off. In your case, I suspect your battery capacity isn't really up to par at that age.

Totally agree with you. That's the case with most cars. What stunned me was the fact that the design is meant to achieve higher fuel efficiency but to charge the battery properly you still need to run it on the highway. The more things change, the more they stay the same!

[ewalk]

I've swapped out the old battery so now we'll see if that fixes the issue. I suspect it will.
I used the Schwaben code reader to register the battery but it does not allow me to change the Ah (from 90 to 95). Battery has the same CCA of 900 as the previous. I'm thinking that should not be too problematic (I hope!).

Anyone else have experience with this?

[Wires]

Originally Posted by ewalk

Totally agree with you. That's the case with most cars. What stunned me was the fact that the design is meant to achieve higher fuel efficiency but to charge the battery properly you still need to run it on the highway. The more things change, the more they stay the same!

"For most people" standard use just addresses this. But for them to hit EPA numbers, they roll back everything to minimize parasitic losses. The car is only trying to git 75-80% of full battery charge to leave capacity for their "efficiency dynamics" to generate more power when you are coasting.

My 2008 GMC pickup had the same issue. Basically barely charged when idling. So if you thought you'd charge the battery by letting it idle, you were wrong (I tried, dealer corrected me! )

[ewalk]

Well it has been a couple of weeks and the car/battery are behaving perfectly. No more steering issues, no nasty battery messages. It has warmed up slightly here but the messages would normally have continued and they have stopped. Most importantly, the power steering is back and there have been no further issues since battery replacement.
Interesting how a battery can affect the electric power steering. A good thing to remember. My first thought when this occurred was rack replacement but that would have been extremely costly. Replacing the battery was much more reasonable!