[Engender]

Up until this week it's been getting colder and colder where I live in Northern Virginia. During this time, I've been getting "battery draining when stopped" warnings. This week, the high has been in the 70s. I finally got around to testing the voltage of my battery today, and it was sitting at 12.6 volts.

I conclude that the parasitic draw could either be something like a glove compartment light, and I finally fully closed the glove compartment, or something related to the colder weather. Does anyone have any thoughts as to what, if anything, would be actively pulling amps if not turned on during colder temperatures?

[Wires]

When it gets really cold, and the battery isn't charging up fully, I used to get that. I'd trickle charge the battery overnight, and it wouldn't show again.

For me, it also mentioned "iDrive running when the car is off" or something like that. On my last service I mentioned it to the SA, and they updated software in the iDrive.

Not sure if that fixed it since COVID happened, and I spent a year working from home and never had the car reach those conditions again.

[Engender]

Do you remember approximately when this was that you got the iDrive update? Also, could you take a look at your version number and share it?

[Billfitz]

The most common reason for weak charge is infrequent driving and/or short trips. The car always has something drawing current, which is a problem when the battery doesn't get fully charged or isn't charged for extended periods. It's made worse when temperatures go down, as batteries don't hold a charge as well when cold. In winter I have to deal with the trifecta, as I seldom drive more than one day a week and then not a long distance, and it's cold. I use a battery maintainer and have never had a charge problem, even though my battery is now over 7 years old.

[Wires]

Originally Posted by Engender

Do you remember approximately when this was that you got the iDrive update? Also, could you take a look at your version number and share it?

I think it was May 2020.

When I look at the iDrive update screen:
Media: MB-001.056.001
Phone: TB-001.056.001

[Engender]

Originally Posted by Billfitz

The most common reason for weak charge is infrequent driving and/or short trips. The car always has something drawing current, which is a problem when the battery doesn't get fully charged or isn't charged for extended periods. It's made worse when temperatures go down, as batteries don't hold a charge as well when cold. In winter I have to deal with the trifecta, as I seldom drive more than one day a week and then not a long distance, and it's cold. I use a battery maintainer and have never had a charge problem, even though my battery is now over 7 years old.

Yeah, but I got this battery in August . . . and I'm not realizing that I was having problems during the summer, so my whole "it's cold related" theory is undermined.

[visionaut]

I’ve only gotten the ‘battery drained while stopped’ on my iDrive after the car sat for 4-5 days in sub freezing weather. So it could definitely just be cold-related.

Batteries don’t like cold. The drain may not necessarily be because of any unplanned/problematic parasitic draw, but just normal ‘car off’ electrical activity. My 6 y/o battery’s ’health’ drops into the low 90s at times during the winter, whereas it’s always at 98%+ in the summers. Which is why I now plug in a battery tender during the winter months if there’s any chance I won’t be using it regularly.

[Billfitz]

Originally Posted by Engender

Yeah, but I got this battery in August . . . and I'm not realizing that I was having problems during the summer, so my whole "it's cold related" theory is undermined.

Not to mention that what you call cold I call balmy. You may need to do an ammeter check of your system to find the source of a parasitic power draw.

[Engender]

Today, when I was driving, I was getting a reading of 14.7 volts on the hidden diagnostic menu. I did see a worrying reading of 12.3 after the car had stopped, and I got the "vehicle charge low" warning. However, when I drove the car again and then stopped, I took video of the voltage at 14.8 prior to shutting off the car, and the dropping to 13.7 and then 13.4, at which point I got the "Battery Discharged: Start Engine" warning.

Well, at 13.4 volts the battery is not discharged, is it?

I just went out with a multimeter and the battery reads 12.94 volts after sitting for about an hour.

It's got to be the intelligent battery sensor, right?

[Billfitz]

13.4 is normal. But it shouldn't drop from 13.4 to 12.94 in an hour. Overnight maybe. What may be happening is that the sensor detects that the voltage is dropping much faster than normal and that's why you get the warning. If it went down 0.5 volts in an hour it could go down 5 volts overnight.

[Engender]

Originally Posted by Billfitz

13.4 is normal. But it shouldn't drop from 13.4 to 12.94 in an hour. Overnight maybe. What may be happening is that the sensor detects that the voltage is dropping much faster than normal and that's why you get the warning. If it went down 0.5 volts in an hour it could go down 5 volts overnight.

Does that suggest to you it's still a parasitic draw? Or could the new battery I got in August just be bad?

[visionaut]

You did register the new battery with the car when it was installed in August, right? Otherwise it’s charging profile won’t be right.

What triggered your new battery install? We’re you getting similar errors or iDrive messages prior as well?

From ISTA:
“The vehicle electrical system is informed about the battery characteristic data, such as type, size, age and current power capacity. If the performance readiness drops below a defined minimum, a Check Control message will be generated to advise the driver that the battery must be replaced.

When installing a new vehicle battery, the battery must be registered with the vehicle electrical system.

When retrofitting, a more powerful battery may be used. Standard batteries may always be replaced by AGM batteries with the same specifications. When installing a battery of a different size or a different battery type, this change in battery data must also be programmed into the vehicle.”

[Billfitz]

Originally Posted by Engender

Does that suggest to you it's still a parasitic draw? Or could the new battery I got in August just be bad?

Bring the battery up to full charge. Measure the voltage, disconnect the negative terminal, measure the voltage again the next morning. You'll have your answer.

[Wires]

Keep in mind the car typically only charges to around 70% capacity, so short trips pull it down faster. For me it showed up in -30C weather since the battery was cold, started drained it and my commute was only 20 minutes so it never recovered. That's why trickle charging it overnight fixed it for me.

You might want to load test the battery as well. Just because it was "new" doesn't mean it hadn't been sitting on the shelf for a very long time in a discharged state (which is bad).

[visionaut]

IBS Info for you:

[Engender]

Hello everyone! I did get a trickle charger, but I didn't have a long enough extension cord until now. I did use the trickle charger, but it became disconnected, likely because someone stepped on it during the charging process. The last time I tried to charge the battery was Saturday night (11/5/2022). Yes, I was using the engine charge terminals—I did not connect the trickle charger directly to the battery. Also, the trickle charger got up to the "slowing the charge voltage" stage before it was disconnected.

I have not driven the car since.

This afternoon, Wednesday (11/9/2022), I checked the battery voltage at the battery and it was 12.75. I checked because I plan to drive it again tomorrow, and I wanted to see if I would need to use the trickle charger over night to make sure the car would start. Given the battery is fully charged, I don't expect that starting the car tomorrow morning will be a problem.

Thoughts?

[Engender]

Update! I fully charged the car last night using the BMW-branded CTEK trickle charger. Using a multimeter, I read a voltage of 13.10 at 8 pm. I then removed the negative battery terminal.

This morning at 11 am, I read a voltage of 13.16. Before reattaching the negative battery terminal, I checked the amps and got a reading of 8.03. Of course, this reading was done without giving the car time to shut itself down. I couldn't do that today, because it was raining.

So, I think we can rule out an issue with the battery. I perform another draw test tomorrow after I've left the trunk open for an hour.

[Engender]

An update. I've been seeing the warning on and off (more often on than off) since this started in August. I got a multimeter with an automatic battery charger sometime late 2022, and the battery tested fine.

I've been busy and not had time to let the car sit with the negative battery terminal removed for an hour. I'll try to do that this weekend.

[Engender]

Resurrecting this thread to add more information. I finally got around to taking the negative battery cable off after the car thought it was locked for over 45 minutes. I measured a draw of 1.68 amps.

I would say that this is likely a parasitic draw. Thoughts?

[jdhillon656]

Originally Posted by Engender

Resurrecting this thread to add more information. I finally got around to taking the negative battery cable off after the car thought it was locked for over 45 minutes. I measured a draw of 1.68 amps.

I would say that this is likely a parasitic draw. Thoughts?

which multimeter did you use ?

how did you diagnose?

Please & Thank you

[Engender]

I'm not sure the multimeter matters, but do try to use the 10A option so that you don't blow the multimeter out.

I opened my trunk, and then used a screwdriver to close the trunk lock while it was still open. I then used the lock/alarm function on my key, but turned it off immediately. I waited 45 minutes, and then removed the negative cable from the car battery in the trunk. I measured the amplitude between the negative cable and the negative terminal on the battery.

[jdhillon656]

I tried to disconnect it after 45 minute but the security alarm goes on and does not stop chiming even the battery is disconnected.