[Blue Angel]

So we've had some nice, cold, typical Ottawa January weather the last few weeks with many overnight lows in the range of -30C to -34C (-22F to -29F) and have been seeing battery discharge warnings when starting the car (Battery discharging while stopped) and shutting the car off (Battery discharged, start engine).

I did some research and it seems this was popular for early pre-LCI F10s, but not much about it in later cars.

Has anyone gotten to the bottom of this? Or is it just a symptom of cold weather and will pass when things warm up?

The car runs and starts fine, but occasionally the comfort/auxiliary features get cut early (delayed radio power, interior lights etc.).

EDIT: my car is a '16 535d, Canadian diesel model, same as 530d elsewhere.

[cdmulders]

Originally Posted by Blue Angel

I did some research and it seems this was popular for early pre-LCI F10s, but not much about it in later cars.

I would get this message (or one like it) while living in Ottawa with my F10 as well (2012 - 2015 with my at the time brand-new 535xi). It happened rarely, only on the coldest days, and may have been tied to me leaving my iPod plugged in to the armrest for music. I have not had this message when we were in Europe (much milder weather) nor now while living on the west coast (also much milder weather).

[Blue Angel]

Thanks for the info!

Coincidentally:

1. I just installed an aftermarket Android display unit, so maybe there's something in there drawing current?

2. It's only -8C outside this evening, and moving the car to shovel the driveway I got no errors when starting/stopping the car, the first time in nearly a week!

3. I had no such errors last winter, but we didn't get any really cold nights last year.

Your iPod experience makes me wonder about the Android HU. I'll have to see if the car remains error-free during warmer weather.

Thanks for your input!!!

[Aussie_550i]

I've got a 2011 550i that says the same thing to me most mornings. I live in Australia. From what I've been able to find out is that the CAS is the culprit.

I installed an Android HU a few months back and it made no difference to the frequency of the warning.

I also tried installing a new 105Ah BMW battery and registered it hoping that the extra Ah would help. I was sadly mistaken there

[Surly73]

[ I swear if I've posted about this once, I've done it over a dozen times ]

"Discharging while stopped" means that the IBS has detected an active current draw above acceptable limits when everything is supposed to be sleeping. It generally reacts by cutting off that circuit branch until the car is restarted. Your new head unit is EXTREMELY SUSPECT but, in normal cases, it could be just about anything. On my F10 it was a parking brake actuator that was not sleeping properly. You may need ISTA or professional help to track it down. It does NOT mean that you need a new battery, and chances are replacing the battery because of this warning is wasted money. Sometimes disconnecting the battery (fully rebooting the car) could fix a glitchy module so it's worth trying.

The "Discharged" message is self-explanatory. The parasitic loss logged above, combined with your driving habits and the weather has resulted in your battery being discharged. It needs charging. Charge it. Personally I'd recommend a plug in charger, just make sure to charge from the under hood terminals and not directly on the battery or the car won't know that you've charged it.

Whenever a vehicle battery is below 80% SoC (state of charge) it is being damaged by sulfation and permanently losing capacity the longer it stays this way. Take care of it.

If you have a situation where you can plug the vehicle in overnights, I recommend something like a CTEK MXS 5.0 or NOCO Genius5, ensuring that you use AGM mode (and winter mode, when appropriate) assuming your F10 still has an AGM battery.

[Blue Angel]

Thanks for your feedback, Surly. I agree 100% with your thoughts and you're surely right about something drawing power while the car is off.

I got a couple random messages on the HU after starting the car, something to the effect of "The call will end when the BT connection... something something." Makes me think the car's BT module was staying powered on after the HU shut down. I have been messing with settings trying to get BT sorted with this HU so I wouldn't be surprised if that was the case. I did a full factory reset of the HU and haven't seen the message since.

It's also been MUCH warmer the last few days (-5 to -15), so that may be helping as well, lining up with cdmulders experience.

QUESTION: Battery State Of Charge. BimmerLink is telling me my SOC is only 69-70%, even after (and during) extended drives of 30 min or more. Is this just a function of the battery's age, or does the charging circuit need a hard reset or something? Voltage while driving looks decent at 14.5-14.7, even hitting 15.0 for short periods after starting on cold days.

I have a battery charger, but it's a 15+ year old 12A Mastercrap model with no AGM mode. My car still has an (original?) AGM 105Ah battery which still cranks the engine fine. It's a little sluggish on those -30 mornings, but who isn't? Should I use this car as an excuse to buy a nice new charger?

[Surly73]

Originally Posted by Blue Angel

Thanks for your feedback, Surly. I agree 100% with your thoughts and you're surely right about something drawing power while the car is off.

I got a couple random messages on the HU after starting the car, something to the effect of "The call will end when the BT connection... something something." Makes me think the car's BT module was staying powered on after the HU shut down. I have been messing with settings trying to get BT sorted with this HU so I wouldn't be surprised if that was the case. I did a full factory reset of the HU and haven't seen the message since.

It's also been MUCH warmer the last few days (-5 to -15), so that may be helping as well, lining up with cdmulders experience.

QUESTION: Battery State Of Charge. BimmerLink is telling me my SOC is only 69-70%, even after (and during) extended drives of 30 min or more. Is this just a function of the battery's age, or does the charging circuit need a hard reset or something? Voltage while driving looks decent at 14.5-14.7, even hitting 15.0 for short periods after starting on cold days.

I have a battery charger, but it's a 15+ year old 12A Mastercrap model with no AGM mode. My car still has an (original?) AGM 105Ah battery which still cranks the engine fine. It's a little sluggish on those -30 mornings, but who isn't? Should I use this car as an excuse to buy a nice new charger?

I continue to suspect your new HU

SoC - what you're seeing is in line with physics. AGMs especially take a long time to charge when near fully charged. It gets worse with age. The voltage when the car is "charging" should be a target of 14.8.

Two things -

1/ the battery absorbs very slowly at higher SoC

2/ Once the car believes you're at 80% it will drop voltage to the mid 13s except when the little blue arrow under the speedo is pointing at the battery (when coasting in gear) when it will go back up to 14.8. This makes things even worse. You will effectively never get past 80% depending on the charging system alone.

This is the "regenerative braking" (which is a load of marketing crap) to eek out a little more fuel efficiency over the entire fleet. On one hand - every little bit helps. On the other - this kills batteries faster and adds a lot of complexity to the vehicle electronics. We're saving FUEL, but are we really saving CARBON, or money?

Yes, I would personally use this as an excuse to buy a CTEK or NOCO charger with a true temperature-compensated AGM mode. Mine is wall mounted beside the car and I use it overnight (or multiple days in COVID times) a decent amount. More in cold weather. The SoC histograms in ISTA show I'm at 80% SoC something like 97%+ of the time and 3% at 70-80 (based on my memory).

I recently got a "Solar BA9" battery analyzer. Using its CCA test mode (which uses impedance and some math to compute battery health and current CA/CCA performance) it tells me that my 2015 dealer warranty battery can still produce 724 CCA or 85% of original. Around here, East Penn batteries for F10 applications have shot up to over $700 in COVID times. Other brands are less, but I want an East Penn. Without the tester I probably would have bought one just to be safe based on age. Without the charger I probably would have failed the battery long ago due to sulfation.

[Blue Angel]

Originally Posted by Surly73

I continue to suspect your new HU

It's going to be quite some time before I don't suspect this thing! Luckily it seems to be behaving since the reset.

Originally Posted by Surly73

SoC - what you're seeing is in line with physics. AGMs especially take a long time to charge when near fully charged. It gets worse with age. The voltage when the car is "charging" should be a target of 14.8.

Two things -

1/ the battery absorbs very slowly at higher SoC

2/ Once the car believes you're at 80% it will drop voltage to the mid 13s except when the little blue arrow under the speedo is pointing at the battery (when coasting in gear) when it will go back up to 14.8. This makes things even worse. You will effectively never get past 80% depending on the charging system alone.

This is the "regenerative braking" (which is a load of marketing crap) to eek out a little more fuel efficiency over the entire fleet. On one hand - every little bit helps. On the other - this kills batteries faster and adds a lot of complexity to the vehicle electronics. We're saving FUEL, but are we really saving CARBON, or money?

Yeah, this all makes sense - I see voltages above 14.5 very rarely, usually only just after starting the car.

LOL, you're preaching to the choir! "Regenerative braking", right! There's not a friction brake on any car that regenerates anything, but the marketing wank is strong these days!

Originally Posted by Surly73

Yes, I would personally use this as an excuse to buy a CTEK or NOCO charger with a true temperature-compensated AGM mode. Mine is wall mounted beside the car and I use it overnight (or multiple days in COVID times) a decent amount. More in cold weather. The SoC histograms in ISTA show I'm at 80% SoC something like 97%+ of the time and 3% at 70-80 (based on my memory).

OK, so I blame you then. I just got a NOCO Genius 10. Haven't unboxed it yet but I plan to put it to work today on both my wife's E90 regular battery and my F10 AGM battery. The E90 battery is nearly new, but mine is circa 2015 (assuming it's original) and I'd like to keep it a while.

Strange - According to BimmerLink, before setting out on Friday afternoon my F10 SoC was 65%, after a 40 min highway drive it had fallen to 63%, then after sitting for 7 hours and driving 40 min back home at night it was at 80%. My previous car's charging strategy included a "headlight mode" where any time the headlights were on it stepped up the voltage to 14.5-ish. Could this be what's happening with the F10 as well?

Originally Posted by Surly73

I recently got a "Solar BA9" battery analyzer. Using its CCA test mode (which uses impedance and some math to compute battery health and current CA/CCA performance) it tells me that my 2015 dealer warranty battery can still produce 724 CCA or 85% of original. Around here, East Penn batteries for F10 applications have shot up to over $700 in COVID times. Other brands are less, but I want an East Penn. Without the tester I probably would have bought one just to be safe based on age. Without the charger I probably would have failed the battery long ago due to sulfation.

Nice.

Here you go: https://remybattery.com/intimidator-9a95r-battery.html
$75 shipping to NY, not sure where you're at.

I've been looking at the Odyssey H8. I had fantastic luck with an Odyssey PC680 motorcycle battery in my Corvette. That little 15lb battery started that car no problem for about 10 years, even at slightly below freezing temps, and even after being run down several times as it's a deep cycle design (and it had very little capacity). I've still got it in the garage and I'm sure after sitting for over two years since I last looked at it it's still fully charged.

The Odyssey H8 is not a cheap battery, but if it scales up the performance I got from the little PC680 it will be an absolute beast of a battery. It's smaller than the H9 OEM AGM battery but still matches its CCA rating. I'm positive if I ever go that route I'll never need another battery for this car as long as I own it.

https://www.odysseybattery.com/produ...attery-49-950/

[Blue Angel]

So I put my old PC680 on this new NOCO charger in AGM mode. It pulsed through its lights and in less than a minute had determined this incredible little battery is still fully charged.

I bought it in 2007, it sat untouched in my basement until 2009 at which point it was still charged fully and started the Vette like a champ. It continued to do so for 10 years and roughly 80k kms, but started getting a little sluggish on cold mornings when parked outside. By that time the car had gone into storage and the battery came out.

I tried it in my Cruze for fun and it worked fine for a few months, then it sat in my garage since before the pandemic and it's still fully charged today. I have no use for it, but maybe I can use it in a portable generator or something. I've had it so long it's darn near got sentimental value at this point!!!

[Blue Angel]

Immediately after charging this battery showed 12.9-13.0v, and after sitting for 7 hours it shows 12.8v. According to Odyssey, a fully charged battery at 100% capacity should read 12.84v or higher (sitting disconnected min 6 hrs after charging), so this one is still doing pretty good.

Ok, I'm not going to try to sell you a battery anymore.

[HighlandPete]

Originally Posted by Blue Angel

Strange - According to BimmerLink, before setting out on Friday afternoon my F10 SoC was 65%, after a 40 min highway drive it had fallen to 63%, then after sitting for 7 hours and driving 40 min back home at night it was at 80%. My previous car's charging strategy included a "headlight mode" where any time the headlights were on it stepped up the voltage to 14.5-ish. Could this be what's happening with the F10 as well?

My experience, simply driving to charge the battery doesn't necessarily work as we would like. I've checked the sleeping voltage of a partly discharged battery (~12.35V), before a trip of say 35 miles and then 24hrs later, it is no different.

Highway driving is the worse type of driving, as there are little over-run situations, when the alternator gives maximum charge. You need lots of over-run opportunities to 'up' the SoC, when the voltage is in the phase where the alternator only 'supports' the battery, not charge it. SoC has to drop to quite a low SoC threshold (BMW are not clear on this lower threshold, I suspect ~60% from some of the data), before we get the energy management to switch to a conventional charge regime. Once back above that threshold, energy management returns to the 'support' phase and we need the over-runs to continue to improve the SoC.

It goes against what we may be used to with 'simple' charging systems, where a steady run was best for charging a battery in the vehicle.

[Blue Angel]

Interesting, thanks for the info.

I wonder if any of these parameters can be changed in ISTA? Would be nice to see that charge/support threshold a little higher, say 75% or so.

[ctcarbonari]

Re: Strange - According to BimmerLink, before setting out on Friday afternoon my F10 SoC was 65%, after a 40 min highway drive it had fallen to 63%, then after sitting for 7 hours and driving 40 min back home at night it was at 80%

I've experienced these same type of "counter intuitive" SoC readings. (i.e. different charging rates while driving under "same" conditions). I use Bimmerlink as well to monitor my battery ever since I had a CA issue.

[Trainwreck914]

Seems like a lot of the old e39 crew is now on f10's. My 2011 535i xdrive has done this since I ones it. Battery discharge message. Battery was original to the car and about 10 yrs old when I decided to replace it. Registered the battery but still get the message. Can't pinpoint where the parasitic draw is

[ezaircon4jc]

Originally Posted by Trainwreck914

Seems like a lot of the old e39 crew is now on f10's. My 2011 535i xdrive has done this since I ones it. Battery discharge message. Battery was original to the car and about 10 yrs old when I decided to replace it. Registered the battery but still get the message. Can't pinpoint where the parasitic draw is

Try one of the door actuators. They seem to be an issue with comfort access.

[Trainwreck914]

I don't have comfort access