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Discussion Starter · #1 ·
Help please! Had a replacement battery a few weeks ago (flat battery). 2 weeks later the battery was flat again. Garage can't indentify any problems (alternator ok, and says there is no constant drain). They said they said that they found a technical bulleting that said the media system can sometome drain the battery and requires an update to fix it.

Garage wants to charge £120 to do this, but I feel like this is something that can be done DIY. I found this link BMW Software Update | BMW.com but I'm not sure if this is the right update. Has anyone else had this problem?

BMW 320D ED Sport Touring 2016

Thank you
 

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Hi

Do you have any aftermarket items installed in the car that didn’t come from BMW?
This includes cigarette lighter accessories, radar detector, phone chargers, after market radio , lights etc?

when you park your car, do you lock it or leave it unlocked in the garage?

how long does the car sit between starts and how many miles do you drive a day on average?

Lastly when your car has been sitting for longer then 15 mins do you see any lights still illuminated on dash or other location?

We have to dissect the problem, You have to determine if after the car Is started if your alternator is actually charging your battery. You need a voltmeter to check the battery for 14v+
Then test it again from the contacts under the hood.
These readings should be done before and after you start the car.

it’s possible that your alternator could be going or you may have a bad ground wire somewhere. They start turning green and corrode which in turn reduces the ability to put charge back into the battery.
 

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Discussion Starter · #5 ·
Hi

Do you have any aftermarket items installed in the car that didn’t come from BMW?
This includes cigarette lighter accessories, radar detector, phone chargers, after market radio , lights etc?

when you park your car, do you lock it or leave it unlocked in the garage?

how long does the car sit between starts and how many miles do you drive a day on average?

Lastly when your car has been sitting for longer then 15 mins do you see any lights still illuminated on dash or other location?
It's been in the garage and they have said that they cannot identify a problem or that there is any unusual draw on the battery. They said they found a technical bulletin that said the radio could be draining the battery and it needs to be updated to fix it. The garage want to charge £120 to do it.

I found the link above which suggested you could update yourself. Is this the same update?

I spoke to BMW and they also want to charge £90 to do the update. Doesn't sit right as the update is to fix a known issue they have found (should be free? Or am I being unreasonable?)

I've already spent £420 on diagnostics and a new battery so don't really want to spend any more money on something that 'might fix it.'

It was only back with is for 2 weeks before the battery was dead. Whilst we didn't drive it much (or far) this seems too quick for it just to be caused by the cold weather and the alarm etc that will be using power when stationary.

To answer your question through, we do have a tow bar and a phone charger. Nothing else after market. Left on drive (usually locked) and don't haven't noticed any light being on after 15 mins.

Cheers
 

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Nuclear engineer
02/2012 X5 35d M57Y CPO 100K miles NOKIAN WR G3 20K miles
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19,439 Posts
If your alternator has a sprag clutch pulley then it charges the battery only on overrun. All other times it only maintains the accessory loads.
 

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Discussion Starter · #7 ·
If your alternator has a sprag clutch pulley then it charges the battery only on overrun. All other times it only maintains the accessory loads.
Do you know if mine will have a sprag clutch pulley? It's a 2016 320d ED Sport. What you you mean by overrun? Do you mean it only charges after a certain amount of time? (Sorry I'm a complete newbie)
 

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It's been in the garage and they have said that they cannot identify a problem or that there is any unusual draw on the battery. They said they found a technical bulletin that said the radio could be draining the battery and it needs to be updated to fix it. The garage want to charge £120 to do it.

I found the link above which suggested you could update yourself. Is this the same update?

I spoke to BMW and they also want to charge £90 to do the update. Doesn't sit right as the update is to fix a known issue they have found (should be free? Or am I being unreasonable?)

I've already spent £420 on diagnostics and a new battery so don't really want to spend any more money on something that 'might fix it.'

It was only back with is for 2 weeks before the battery was dead. Whilst we didn't drive it much (or far) this seems too quick for it just to be caused by the cold weather and the alarm etc that will be using power when stationary.

To answer your question through, we do have a tow bar and a phone charger. Nothing else after market. Left on drive (usually locked) and don't haven't noticed any light being on after 15 mins.

Cheers
I have a ton of questions, where is the old battery , did you turn it in ? If not, try charging it to see if it can maintain a charge it if it’s not older then 2-3 years.

Unplug the phone charger when not in the car. I’ve seen phone charger element decay and I’ve seen older style chargers droop into the side of seats and make contact with the metal seat track.

As for the dealer, speak to the service manager explain that you’ve already invested £420 with them to fix this very issue and it should be gratis as they never fixed it.

if that doesn’t work, ask for a greatly discounted price as a good gesture from the dealership. I would have them apply the fix if and only if that can guarantee that will fix the drain.
If they won’t, spend that money on a new CTEK MXS 5.0 12v 4.3a battery charger and maintainer.
 

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Nuclear engineer
02/2012 X5 35d M57Y CPO 100K miles NOKIAN WR G3 20K miles
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19,439 Posts
Do you know if mine will have a sprag clutch pulley? It's a 2016 320d ED Sport. What you you mean by overrun? Do you mean it only charges after a certain amount of time? (Sorry I'm a complete newbie)
To minimize emissions and maximize fuel economy late model BMW recover the energy stored in the alternator (rated to spin at 20,000 RPM) and the motor on trailing throttle.
 
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