Battery low warning sign on dash after listening to stereo for a while

[MightyMouseTech]

Usually if you are not driving it every day, and driving it for at least a half hour each time, the battery is not getting fully charged. Continued use like this will sulfate the plates and the battery will just get weaker and weaker.

Using heated seats, and heated mirrors and A/C will all increase the amount of time you have to drive to charge the battery fully.

It is also not just having the radio on, if you have the car "on" there are dozens of computers running on top of the power to run the radio. Plus if you leave your headlights in "auto" and have the headlights stay on after you shut off the car all use a lot of power.

Our cars use a lot of charge if they are on, the alternator can only charge it so fast without damaging the battery.

A battery is just a temporary storage device, you have to put back what you use, if you don't the plates in the battery will sulfate.

I compare it to a gas tank. Your tank can only hold so much. It would be like expecting to be able to go 600 km when you only have a 1/4 tank, you have to fill it up.

[evoiii90]

This definitively doesn't look normal, either your battery is dying and/or there is a controller/device that is draining too much current.
If the car is giving you the "even lower battery" sign, dealer should be able to pull and error/warning from one of the car controllers and not give some BS excuse like "users fault".

I will take it back to the dealer, or an alternative one if the one you're taking it doesn't cooperate.

And on a side note, after reading BMW AG is going to cut cost like crazy to the $5.5 billion tune, I would expect more and more warranty claims being denied. They just started this with the announcement about new owners on used MY 2014 and up cars are NOT going to get the free maintenance program benefits anymore when the car change hands even if the car is still under 4 year / 50k miles. Unfortunately this move will bring resale vales somewhat lower, not to mention the rise in quality problems we're seeing which I attribute in part to this cut cutting effort...

Originally Posted by mccand

FWIW, my 1M has had the "low battery" light come on, even though I drive it regularly and only have radio on w/ car off for a couple of minutes. Sometimes it comes on right when I start it up too. Stealership said battery was low on charge, & recharged it, and said don't use radio too much with car off (I didn't!). It always starts fine, and did not stop any features from going as far as I can tell. After some "low battery" warnings, it said "even lower battery" or some such thing & showed an image of the car on a lift.

It still happens occasionally (happened after a 2 week period of not driving); I hope this goes away, not sure what it is (battery issue, sensor issue, charger issue), but I hope it gets resolved before warranty is up! It is too intermittent now to diagnose it well..

[evoiii90]

Even though I agree with you that there are a lot of "things" in the car that use energy and not only the stereo, this is no excuse for having this kind of issues with the battery / charging system.

This is either a design problem and/or a component problem (battery, battery sensor, software sensing system, etc). No matter how many devices use power in the car at the same time, the system SHOULD be designed to handle it all to a reasonable level, either by having the right size battery and/or by having the right throughput charging device.

The 1M uses the same battery (61 21 7 553 951) as the E9x and some other models, so is not the 1M has special lower weight / smaller energy capacity battery which might lead to shorter battery usage time. I used to have an E90 M3 and never had this problem, even when using the stereo after several hours, so either there is a problem specific to a controller/device on the 1M draining too much current when the car is not in use, or the software measuring the battery charing level threshold on the 1M is off being over sensitive so the car shutdowns after little while after shutting the engine off.

Whatever the cause of the problem is, this behavior should NOT be considered normal...

Originally Posted by MightyMouseTech

Usually if you are not driving it every day, and driving it for at least a half hour each time, the battery is not getting fully charged. Continued use like this will sulfate the plates and the battery will just get weaker and weaker.

Using heated seats, and heated mirrors and A/C will all increase the amount of time you have to drive to charge the battery fully.

It is also not just having the radio on, if you have the car "on" there are dozens of computers running on top of the power to run the radio. Plus if you leave your headlights in "auto" and have the headlights stay on after you shut off the car all use a lot of power.

Our cars use a lot of charge if they are on, the alternator can only charge it so fast without damaging the battery.

A battery is just a temporary storage device, you have to put back what you use, if you don't the plates in the battery will sulfate.

I compare it to a gas tank. Your tank can only hold so much. It would be like expecting to be able to go 600 km when you only have a 1/4 tank, you have to fill it up.

[M3 Adjuster]

Originally Posted by evoiii90

Even though I agree with you that there are a lot of "things" in the car that use energy and not only the stereo, this is no excuse for having this kind of issues with the battery / charging system.

This is either a design problem and/or a component problem (battery, battery sensor, software sensing system, etc). No matter how many devices use power in the car at the same time, the system SHOULD be designed to handle it all to a reasonable level, either by having the right size battery and/or by having the right throughput charging device.

The 1M uses the same battery (61 21 7 553 951) as the E9x and some other models, so is not the 1M has special lower weight / smaller energy capacity battery which might lead to shorter battery usage time. I used to have an E90 M3 and never had this problem, even when using the stereo after several hours, so either there is a problem specific to a controller/device on the 1M draining too much current when the car is not in use, or the software measuring the battery charing level threshold on the 1M is off being over sensitive so the car shutdowns after little while after shutting the engine off.

Whatever the cause of the problem is, this behavior should NOT be considered normal...

You are incorrect. The only thing not normal is sitting in a car for 90 minutes with the radio playing.

And the " problem specific to a controller/device on the 1M draining too much current " is you, the operator.

Could you indulge us as to WHY you feel that your battery should last 90 minutes playing the stereo on a frequent basis? " Because my previous car did it " is NOT an actual answer. It's a justification. Don't tell us about your previous vehicle.. that means nothing. it's not the same car.. not the same electrical system... and not the same stereo. All it is has in common is a Roundel.


if your commute is less than 30 minutes... why do you then need to sit with the stereo on for 3X the amount of time of your commute? I still can't fathom why on earth you would feel a STOCK battery would be capable of this.?

The BMW audio system automatically shuts off after 20 minutes with key out of the ignition to save the battery.

In order to run the car this long.. it seems that at the least, the key would need to be in the ignition. of course the key in the ignition means that a host of items are still running, most importanly there are dash lights that are illuminated. Is this what you are doing?

As far as a trickle charger.. note the name. it's a SLOW charge and is by no means enough of a charge to power the stereo and also charge the battery at the same time.

You mentioned you have the HK premium sound setup.. This setup has a larger amp more than likely than the base system plus also HK speakers. In my experience, HK speakers are just not very efficient. In addition, the system also has subwoofers under the seats (and an amp is required to run those). my point is, you aren't running a pair of 5 1/4" speakers.... Your amp is running at least 8 speakers and two subs.

" The BMW 1 Series Coupe and 3-door model have two metal matrix tweeters in the mirror triangles at the front, metal matrix mid-range speakers in the front door and a woofer beneath both the driver and passenger seats. Two metal matrix mid-range speakers and two further metal matrix tweeters in the base of the parcel shelf behind the rear outer seats deliver a warm, natural sound "

http://www.harmankardon.com/estore/h...to-bmw-1series

"The powerful 300 watts Logic 7 DSP amplifier was placed by Harman Kardon's specialists in the rear of the car, without impacting the usable surface area"


If you really have a serious need to pump out the jams for 90 minutes at a time.. then go to a car stereo store and get a second battery setup or replace the stock battery with an optima Gel Cel . That's a battery that's actually DESIGNED for the abuse you are subjecting your battery to.

EDIT: I read back more.. if you are working in your garage for hours at a time... and using your car stereo as your music source.. stop wasting your dealer's time and our time and just get a freaking Jawbone, or some sort of bluetooth speaker or a jam box, or god forbid an actual HOME STEREO and play your music through that while you are in the garage! Most of those options are far cheaper than a BMW battery.

I think you are simply underestimating the amount of current needed to run your speakers, particularly the drivers in the subwoofers. I think you are also completely ignoring the fact that a car audio stereo is primarily designed specifically to run when the vehicle is ON, not when it is OFF.

[Eyeman]

My Braille lightweight lasts like 4 mins before I get the low battery warning, so things could be worse.

[MightyMouseTech]

Modern cars use a LOT more current than cars even one generation older. Modern CAN BUS cars now have all the computers linked, so if one is one, they are pretty much all on. I see this problem every day here at Acura on our current generation of cars, people complaining that the battery goes dead after 10-20 mins without the engine running, ranting and raving about the battery must be at fault, when it is actually operator error.

If you want the battery to last hours while the car is off, go get a car from the 80's or 90's.

[mccand]

Just to be clear, I have never listened to the radio for more than 2 minutes with the car off. My commute is about 20 min each way.. and I was gone 2 weeks when the light came on this last time. (it has been about a week now & seems to have subsided for now..). I do feel that this is inadequate battery performance (or sensor problem, etc), though I have, admittedly, not owned a new car for a while... just seems to me that it is draining too easily.

[mccand]

Also, recall that it always cranks just fine/strong... my theory is still a sensor/SW issue...

[evoiii90]

I'm not sure why are you getting all worked up about this since this problem not only happening to me, but also to 5 forum members (Stratus650, rkives, Luca335, Isaacata, mccand) who have posted on this thread. Granted there are several degrees on what's happening, but they are all related to the charging system and the low battery warning sign.

Either way, let me address some comments you've made...

Originally Posted by M3 Adjuster

You are incorrect. The only thing not normal is sitting in a car for 90 minutes with the radio playing.

Why wouldn't be normal ??, because you consider it shouldn't be ??, based on what technical data ??. What would be normal to you ?, zero minutes, 5 minutes ??, 10 ??, 15 ??. And for the number you consider correct ??, what's the technical reasoning behind it and under what conditions ??

How soft or loud should the music be at ?, what type in relation the amount of electrical current consumed per unit of time ?. You are making assumptions and/or affirmations on something you don't know all the details when it happened to me, and worst, didn't care to ask before making comments like the one below.

Originally Posted by M3 Adjuster

And the "problem specific to a controller/device on the 1M draining too much current " is you, the operator.

How nice to make harsh comments... like it'll make your point valid and/or correct.

Do you have some technical background on Electrical, Software, Automotive Engineering to determine and confirm this problem is "operator" related ??. Just because you get the impression it is, it doesn't make it true.

If you have some evidence or at least some valid data points, let's hear them.

Originally Posted by M3 Adjuster

Could you indulge us as to WHY you feel that your battery should last 90 minutes playing the stereo on a frequent basis? " Because my previous car did it " is NOT an actual answer. It's a justification. Don't tell us about your previous vehicle.. that means nothing. it's not the same car.. not the same electrical system... and not the same stereo. All it is has in common is a Roundel.

Not sure why you're making wrong assumptions and hence, posting wrong conclusions. First, the comparison here is 100% relevant just because of the FACT the two cars SHARE MANY components not only on the charging system including the battery and the alternator (same amp rating), and probably many others. Do you think every part of the electrical system on the 1M is unique ??, obviously not, the system is not unique and DOES SHARE many components with the E90 family including the M3.

Do you have a list of parts for the cars I'm comparing and their electrical characteristics like consumption in mA per unit of time based on a constant and replicable use pattern to state the comparison is not relevant and "that means nothing" ??. If yes, please share the details with the rest of us, it'll be very enlighten...

See, the E90 M3 I'm comparing with was almost the same year and had almost the same equipment including the factory high end audio system option, ie, not the default one. If anything, the load on the electrical system on an E90 M3 is probably more on average simply because the major systems like engine electrical load, A/C and sound system are bigger (more speakers) on the E90 M3 than on the 1M, ie, bigger internal cabin volume to cool with A/C on the E90, additional electrical components on the S65 engine (8 TBs vs 1 TB, 2 more coils, more actuators, etc) vs N54, etc.

Also, the 90 minute reference I mention is obviously an approximate of what has happened to me. Sometimes it has been way less, probably the 90 min is on the top side. Granted, the battery and the current electrical charge it was holding will vary A LOT depending on various factors including how much the car is used, for how long every time, and what electrical load is put when it's been used.

Obviously these two cars have more in common than just a "Roundel", and specifically on "infrastructure" type systems like the electrical one.

Originally Posted by M3 Adjuster

if your commute is less than 30 minutes... why do you then need to sit with the stereo on for 3X the amount of time of your commute? I still can't fathom why on earth you would feel a STOCK battery would be capable of this.?

Did I say my commute was less than 30 minutes and that when I stopped I played the stereo for more than 90 minutes ??. NO, I didn't said that. And even if I did, what facts are you stating that can prove that a 30 minute drive is not enough to charge the battery 100% ??. To conclusively state this you will need to have at least the following data:

- Battery charge level when the less than 30 minute drive started.
- Battery charge level when the less than 30 minute drive ended.

At what % difference of these two values and what amount of time is NOT enough to charge the battery 100% ?, at what starting % is the drive not enough ?? with what car accessories ON and at what level if some accessory has a variable load like A/C, stereo ?. What external conditions ??, ie, outside temperature ?, at what battery age ??. Without all or at least some of these data it would all guessing to say a commute of X amount of time is not enough to get a 100% battery charge that can sustain an electrical load like the audio system for Y amount of time when engine if off.

There are many factors that play a role in this so saying less than 30 minutes is not enough is the wrong conclusion if other factors are not taken into account. Under some conditions it might be not enough, on some others it might be more than enough.

Originally Posted by M3 Adjuster

The BMW audio system automatically shuts off after 20 minutes with key out of the ignition to save the battery.

In order to run the car this long.. it seems that at the least, the key would need to be in the ignition. of course the key in the ignition means that a host of items are still running, most importanly there are dash lights that are illuminated. Is this what you are doing?

Yes, the audio system will shutoff at 20 min, or less, I haven't actually measured when the keyfob is not inserted. As we all know when the keyfob is inserted the system can be in what used to be called the "accessory" position (not sure of the new name, if different) which means the stereo can be turned on. The system doesn't has to be in the "on/start" position for the stereo to be on, which is when all the dashboard lights will illuminate meaning all systems are "on".

When I have listened to the stereo with the engine off, system is in "accessory" mode with the keyfob in.

Originally Posted by M3 Adjuster

As far as a trickle charger.. note the name. it's a SLOW charge and is by no means enough of a charge to power the stereo and also charge the battery at the same time.

True, is a slow charge, but again, there are other factors that come in to play if the charger is connected when the audio system is on: volume level, type of music, battery charge level, etc. It's a fact that if the trickle charger is connected, battery charge level will decrease at a lower rate than without it given the all other conditions are the same.

And then there is the fact all trickle chargers are not the same, even at the same amp output level because of how they measure battery charge level.

Originally Posted by M3 Adjuster

You mentioned you have the HK premium sound setup.. This setup has a larger amp more than likely than the base system plus also HK speakers. In my experience, HK speakers are just not very efficient. In addition, the system also has subwoofers under the seats (and an amp is required to run those). my point is, you aren't running a pair of 5 1/4" speakers.... Your amp is running at least 8 speakers and two subs.

" The BMW 1 Series Coupe and 3-door model have two metal matrix tweeters in the mirror triangles at the front, metal matrix mid-range speakers in the front door and a woofer beneath both the driver and passenger seats. Two metal matrix mid-range speakers and two further metal matrix tweeters in the base of the parcel shelf behind the rear outer seats deliver a warm, natural sound "

http://www.harmankardon.com/estore/h...to-bmw-1series

"The powerful 300 watts Logic 7 DSP amplifier was placed by Harman Kardon's specialists in the rear of the car, without impacting the usable surface area"

If you really have a serious need to pump out the jams for 90 minutes at a time.. then go to a car stereo store and get a second battery setup or replace the stock battery with an optima Gel Cel . That's a battery that's actually DESIGNED for the abuse you are subjecting your battery to.

EDIT: I read back more.. if you are working in your garage for hours at a time... and using your car stereo as your music source.. stop wasting your dealer's time and our time

Nice attitude... Let's see:

a) I never asked you specifically for your input on this problem nor to invest ANY time.
b) If you feel you're wasting your time, simply ignore the post, move on, and try not to make harsh remarks.
c) State your facts and relevant data from where your conclusions are based on to make a valid point that contradict my findings and/or observations.
d) Obviously and based on some other posts on this thread from owners having various degrees of issues related to the charging system, I have all the RIGHT to make the dealer CHECK for a POTENTIAL problem on this, so have all the other owners facing similar issues.

I always welcome constructive criticism and will agree on a conclusion produced by a logical process based on relevant data / facts even if different from a previous conclusion that I might have come up with and mentioned here, but the personal remarks are totally out of place... specially without facts backing them up.

Originally Posted by M3 Adjuster

and just get a freaking Jawbone, or some sort of bluetooth speaker or a jam box, or god forbid an actual HOME STEREO and play your music through that while you are in the garage! Most of those options are far cheaper than a BMW battery.

I think you are simply underestimating the amount of current needed to run your speakers, particularly the drivers in the subwoofers.

I might be underestimating it, but given some of the conditions this problem appears, and from what other owners have experienced and mentioned on this thread, there is definitively something going on with the charging system on these cars, or how it's measured as I have also said. If you haven't experienced, great, but that doesn't mean is not happening.

It's good the car has a warning system, but that doesn't mean there isn't a problem with it by being over sensitive because of what I've experienced and what others forum members have posted here.

Originally Posted by M3 Adjuster

I think you are also completely ignoring the fact that a car audio stereo is primarily designed specifically to run when the vehicle is ON, not when it is OFF.

Neither you nor I know the exact parameters that were taken into account when the audio system was designed nor what were the goals in terms of electrical power consumption vs available electrical power and under what conditions. It might be true the electrical energy demands are obviously going to be met when the engine is on and that the audio system will work at is best when the engine is on given the electrical energy available from the alternator, but that doesn't mean the engineers who designed this system didn't account for energy consumption including the audio system when the engine is off, at least for a certain amount of time.

What amount of time ?, well, that's debatable. And given the fact the comparison with en E90 M3 IS relevant based on what I explained before, then what's happening on the 1M is a short time.

Obviously the battery's energy reserves are not infinite, but that doesn't mean the car should shutdown after the stereo being on for a short period of time like others have reported on this thread, are for some, even without the stereo being on.

It's not a black and white situation, there's a lot of room for grey areas... If you consider the audio system should not be used with the engine off at all, that's your opinion, and unless you come up with valid data points and variables like the ones I've mentioned and asked for, then you simply cannot conclude what you're stating, that's all.

[1mm2]

Originally Posted by M3 Adjuster

I think you are also completely ignoring the fact that a car audio stereo is primarily designed specifically to run when the vehicle is ON, not when it is OFF.

The dealer never informed me of this as the HK system was the only reason I bought the damn car in the first place.

Duped again...

[Berra]

How can you listen to music for 90 minutes straight anyway? My M5 E60 cuts the radio after a short while, so does the X5 40d I have. I would assume that they do it for a reason, save battery. Good luck!

[M3 Adjuster]

Originally Posted by evoiii90

I'm not sure why are you getting all worked up about this since this problem not only happening to me, but also to 5 forum members (Stratus650, rkives, Luca335, Isaacata, mccand) who have posted on this thread. Granted there are several degrees on what's happening, but they are all related to the charging system and the low battery warning sign.

Either way, let me address some comments you've made...

Why wouldn't be normal ??, because you consider it shouldn't be ??, based on what technical data ??. What would be normal to you ?, zero minutes, 5 minutes ??, 10 ??, 15 ??. And for the number you consider correct ??, what's the technical reasoning behind it and under what conditions ??

How soft or loud should the music be at ?, what type in relation the amount of electrical current consumed per unit of time ?. You are making assumptions and/or affirmations on something you don't know all the details when it happened to me, and worst, didn't care to ask before making comments like the one below.

How nice to make harsh comments... like it'll make your point valid and/or correct.

Do you have some technical background on Electrical, Software, Automotive Engineering to determine and confirm this problem is "operator" related ??. Just because you get the impression it is, it doesn't make it true.

If you have some evidence or at least some valid data points, let's hear them.

Not sure why you're making wrong assumptions and hence, posting wrong conclusions. First, the comparison here is 100% relevant just because of the FACT the two cars SHARE MANY components not only on the charging system including the battery and the alternator (same amp rating), and probably many others. Do you think every part of the electrical system on the 1M is unique ??, obviously not, the system is not unique and DOES SHARE many components with the E90 family including the M3.

Do you have a list of parts for the cars I'm comparing and their electrical characteristics like consumption in mA per unit of time based on a constant and replicable use pattern to state the comparison is not relevant and "that means nothing" ??. If yes, please share the details with the rest of us, it'll be very enlighten...

See, the E90 M3 I'm comparing with was almost the same year and had almost the same equipment including the factory high end audio system option, ie, not the default one. If anything, the load on the electrical system on an E90 M3 is probably more on average simply because the major systems like engine electrical load, A/C and sound system are bigger (more speakers) on the E90 M3 than on the 1M, ie, bigger internal cabin volume to cool with A/C on the E90, additional electrical components on the S65 engine (8 TBs vs 1 TB, 2 more coils, more actuators, etc) vs N54, etc.

Also, the 90 minute reference I mention is obviously an approximate of what has happened to me. Sometimes it has been way less, probably the 90 min is on the top side. Granted, the battery and the current electrical charge it was holding will vary A LOT depending on various factors including how much the car is used, for how long every time, and what electrical load is put when it's been used.

Obviously these two cars have more in common than just a "Roundel", and specifically on "infrastructure" type systems like the electrical one.

Did I say my commute was less than 30 minutes and that when I stopped I played the stereo for more than 90 minutes ??. NO, I didn't said that. And even if I did, what facts are you stating that can prove that a 30 minute drive is not enough to charge the battery 100% ??. To conclusively state this you will need to have at least the following data:

- Battery charge level when the less than 30 minute drive started.
- Battery charge level when the less than 30 minute drive ended.

At what % difference of these two values and what amount of time is NOT enough to charge the battery 100% ?, at what starting % is the drive not enough ?? with what car accessories ON and at what level if some accessory has a variable load like A/C, stereo ?. What external conditions ??, ie, outside temperature ?, at what battery age ??. Without all or at least some of these data it would all guessing to say a commute of X amount of time is not enough to get a 100% battery charge that can sustain an electrical load like the audio system for Y amount of time when engine if off.

There are many factors that play a role in this so saying less than 30 minutes is not enough is the wrong conclusion if other factors are not taken into account. Under some conditions it might be not enough, on some others it might be more than enough.

Yes, the audio system will shutoff at 20 min, or less, I haven't actually measured when the keyfob is not inserted. As we all know when the keyfob is inserted the system can be in what used to be called the "accessory" position (not sure of the new name, if different) which means the stereo can be turned on. The system doesn't has to be in the "on/start" position for the stereo to be on, which is when all the dashboard lights will illuminate meaning all systems are "on".

When I have listened to the stereo with the engine off, system is in "accessory" mode with the keyfob in.

True, is a slow charge, but again, there are other factors that come in to play if the charger is connected when the audio system is on: volume level, type of music, battery charge level, etc. It's a fact that if the trickle charger is connected, battery charge level will decrease at a lower rate than without it given the all other conditions are the same.

And then there is the fact all trickle chargers are not the same, even at the same amp output level because of how they measure battery charge level.

Nice attitude... Let's see:

a) I never asked you specifically for your input on this problem nor to invest ANY time.
b) If you feel you're wasting your time, simply ignore the post, move on, and try not to make harsh remarks.
c) State your facts and relevant data from where your conclusions are based on to make a valid point that contradict my findings and/or observations.
d) Obviously and based on some other posts on this thread from owners having various degrees of issues related to the charging system, I have all the RIGHT to make the dealer CHECK for a POTENTIAL problem on this, so have all the other owners facing similar issues.

I always welcome constructive criticism and will agree on a conclusion produced by a logical process based on relevant data / facts even if different from a previous conclusion that I might have come up with and mentioned here, but the personal remarks are totally out of place... specially without facts backing them up.

I might be underestimating it, but given some of the conditions this problem appears, and from what other owners have experienced and mentioned on this thread, there is definitively something going on with the charging system on these cars, or how it's measured as I have also said. If you haven't experienced, great, but that doesn't mean is not happening.

It's good the car has a warning system, but that doesn't mean there isn't a problem with it by being over sensitive because of what I've experienced and what others forum members have posted here.

Neither you nor I know the exact parameters that were taken into account when the audio system was designed nor what were the goals in terms of electrical power consumption vs available electrical power and under what conditions. It might be true the electrical energy demands are obviously going to be met when the engine is on and that the audio system will work at is best when the engine is on given the electrical energy available from the alternator, but that doesn't mean the engineers who designed this system didn't account for energy consumption including the audio system when the engine is off, at least for a certain amount of time.

What amount of time ?, well, that's debatable. And given the fact the comparison with en E90 M3 IS relevant based on what I explained before, then what's happening on the 1M is a short time.

Obviously the battery's energy reserves are not infinite, but that doesn't mean the car should shutdown after the stereo being on for a short period of time like others have reported on this thread, are for some, even without the stereo being on.

It's not a black and white situation, there's a lot of room for grey areas... If you consider the audio system should not be used with the engine off at all, that's your opinion, and unless you come up with valid data points and variables like the ones I've mentioned and asked for, then you simply cannot conclude what you're stating, that's all.

Several of the others that have had issues in the thread don't appear to be using their car stereo like a jam box and likely have actual battery issues that a single replacement will resolve.

I worked for 7-8 years selling home and car audio at a high end retailer and designed systems for vehicles and boats. I've designed systems for competition and also for people that want to jam some tunes on the lake from their boat, so I know what it takes when someone wants to be able to play 10 speakers and cover sound for a large area with the motor off for 90 minutes!


SO yes.. I've tried to help, and even lost my patience a bit. SO... I could tell you all day long about my experiences and I could even show you the math equations that you asked for and do the work but I would still be wasting my time. Since I don't have the exact data on current draw of the system and the complete power specs on the battery from BMW, I would have to use some other numbers that you would eventually then say are " Debatable". Well I'm sorry.. this IS a black and white situation, because Physics isn't debatable. If you could even guesstimate and perform and follow the math equations you would have already done the calculations yourself and you would recognize your folly. You are simply asking more than the system can provide. Post on a car audio forum or better yet, simply Go to a car audio store. Or just go ahead and ignore my advice, and Keep on doing what you are doing and you will eventually find out how expensive a new BMW alternator is.

EDIT: Actually.. the car is probably smarter than you and will probably prevent itself from even attempting to start on a weak battery, thus saving it from frying the alternator. Thank goodness for BMW engineers.

Good luck!

[Artemis]

About battery life stamina, a garage guy once told me the story (urban legend ?) of two youngsters who had borrowed an exotic car for a weekend to show off to the ladies at the local disco. So - as the story goes - there they were on Saturday eve, Beavis and Butt-Head in front of the disco entrance, but not entering the disco: playing music in a loud fashion with headlights on for quite some time and firing up the car several times to spice the oohs and aahs excitement. You guess what happened next: they drained the battery with their antics. The car refused to start anymore (a bit hard to believe that an 80s battery cannot take the strain for a few hours with switched off engine).

Urban legend or not: no pictures exist because it was in an era when smartphones and social media didn't exist yet. Should embarrassing events like that happen nowadays, you bet some folks would gladly take and publish pictures of the scene of jump-start cables connected to the exotic or of the tow truck coming along.

Only hearsay, but with a common sense message: let the engine turn if you want to avoid battery drainage (but, of course, never do it in a closed garage or you might die of carbon monoxide poisoning - better put a radio in your garage).

[M3 Adjuster]

Originally Posted by Artemis

About battery life stamina, a garage guy once told me the story (urban legend ?) of two youngsters who had borrowed an exotic car for a weekend to show off to the ladies at the local disco. So - as the story goes - there they were on Saturday eve, Beavis and Butt-Head in front of the disco entrance, but not entering the disco: playing music in a loud fashion with headlights on for quite some time and firing up the car several times to spice the oohs and aahs excitement. You guess what happened next: they drained the battery with their antics. The car refused to start anymore (a bit hard to believe that an 80s battery cannot take the strain for a few hours with switched off engine).

Urban legend or not: no pictures exist because it was in an era when smartphones and social media didn't exist yet. Should embarrassing events like that happen nowadays, you bet some folks would gladly take and publish pictures of the scene of jump-start cables connected to the exotic or of the tow truck coming along.

Only hearsay, but with a common sense message: let the engine turn if you want to avoid battery drainage (but, of course, never do it in a closed garage or you might die of carbon monoxide poisoning - better put a radio in your garage).

thank god you remembered the PSA about CO poisoning!

[evoiii90]

I've been meaning to post an update for this since early this year...

Back in January BMW replaced my 1Ms battery under warranty. The low battery sign was starting to appear even after a couple of minutes shutting the engine off, and just staying inside the car waiting for a couple of minutes while I was, for example, reading something on my phone while the ignition state wasn't completely off before exiting the car, so the low batt warning sign was coming coming on just after a couple of minutes.

Just took it to the dealer, they read the battery related faults, and replaced the battery, no questions asked.

At the end my battery did have an issue, which made the system shutdown lately even after listening to the stereo for 5 minutes with the engine off...

[rad doc]

Sure, your battery was bad because you abused it. If you had told the dealer how you used the stereo, they would not have replaced the battery. M3 adjuster is right. Sorry

[Em/1]

Originally Posted by rad doc

Sure, your battery was bad because you abused it. If you had told the dealer how you used the stereo, they would not have replaced the battery. M3 adjuster is right. Sorry

Nah, I think both you and M3 adjuster are wrong and I'm quite clear that M3 adjuster is way too full of himself. A few other folks know a little about stereo systems and the typical draw when not playing really loud is very low when using class D which has certainly taken over the "cost effective" home and auto industry and that includes HK. I'd like to know just how M3 gets into the minds of these BMW engineers to know their precise intentions. Me, I think they are pretty bad at electronics compared to some others (and Mike, the Roundel tech would seem to agree). Imagine the audacity and strangeness of wanting to play music at a modest volume while waiting for your youngster to finish his tennis lesson and not wanting to keep starting the engine. That is how I came to find that the battery and/or sensor system must be out of whack on mine--possibly by design of course. My wife's loaded Jag could play for a week, I think; not so my stripper Bimmer.

[evoiii90]

Originally Posted by rad doc

Sure, your battery was bad because you abused it. If you had told the dealer how you used the stereo, they would not have replaced the battery. M3 adjuster is right. Sorry

Right... in your infinite electrical engineering wisdom you just know what was/is my electrical usage pattern meaning you know how many Amps, or mA per hour was the stereo system drawing when listening at moderate volume with the engine off. And you can obviously correlate this usage pattern with the battery's critical current draw per hour and/or peak characteristics so it'll reduce the battery's expected service life, meaning you can conclusively say my usage pattern was the cause of the short battery lifespan.

And BTW, I did tell the dealer I was sometimes using the stereo with the engine off...

The things one has to sometimes read here...

[evoiii90]

Interesting... For some reason I was assuming they kept on using the usual class AB amps instead of class D for car audio. But what you mention sounds about right in terms of amp efficiency and cost while sacrificing some audio quality. Nowadays almost everyone is listening to MP3s and other loosy audio formats so based on the audio source, most people won't notice until their ears are fatigued, which is one of the undesirable outcomes of lossy formats...

Either way, interesting on the class D amps being used nowadays...

Originally Posted by Em/1

Nah, I think both you and M3 adjuster are wrong and I'm quite clear that M3 adjuster is way too full of himself. A few other folks know a little about stereo systems and the typical draw when not playing really loud is very low when using class D which has certainly taken over the "cost effective" home and auto industry and that includes HK. I'd like to know just how M3 gets into the minds of these BMW engineers to know their precise intentions. Me, I think they are pretty bad at electronics compared to some others (and Mike, the Roundel tech would seem to agree). Imagine the audacity and strangeness of wanting to play music at a modest volume while waiting for your youngster to finish his tennis lesson and not wanting to keep starting the engine. That is how I came to find that the battery and/or sensor system must be out of whack on mine--possibly by design of course. My wife's loaded Jag could play for a week, I think; not so my stripper Bimmer.

[eeghie]

Originally Posted by Em/1

... A few other folks know a little about stereo systems and the typical draw when not playing really loud is very low when using class D which has certainly taken over the "cost effective" home and auto industry and that includes HK. ...

The trunk mounted HK unit (option 688) and our default NA HiFi version (option 676) may have class D amplifiers, but although that technology fueled the 2000s 5.1 channel Home theater boom, I've seen no OEM solution to-date that has class D in the headunit (only available in the EU 1M's regular professional radio, option 663, headunit). Mainly due to the difficulty of solving the inherent class D EMI issues so close to a car radio tuner. BTW Class D only has its signature higher efficiency at mid-to high power levels. It would not differ a great deal at low power levels.

In general I would not be surprised about our toss-my-car-around gel/AGM batteries being less capable in the engine-off situation when comparing them to luxury segment vehicles.

[Artemis]

Call me old-fashioned, but if top-notch sound quality is of major importance for you, then get a top-notch installation and install it at the appropriate place allowing the best set-up: home.

[Em/1]

Originally Posted by Artemis

Call me old-fashioned, but if top-notch sound quality is of major importance for you, then get a top-notch installation and install it at the appropriate place allowing the best set-up: home.

Well, I'm sure many, including me agree, but it is hard to take with you in car, and I still like to listen even there!