[grim]

When these AGM batteries failed, did they fail suddenly or give you warning signs, as do most flooded lead acid batteries?

Alas, as suggested by various sites, it was pretty much a sudden thing.

About 10 years ago, when my Cayman battery died, I had heard about AGM batteries and asked about changing from wet cell to AGM and the Dealer said he was going to advise against it because people knew when a wet cell battery was dying. You've lived all your life with it. You just know. But AGMs just "died" unexpectedly so he advised not doing it.

 

[wspollack]

About 10 years ago, when my Cayman battery died, I had heard about AGM batteries and asked about changing from wet cell to AGM and the Dealer said he was going to advise against it because people knew when a wet cell battery was dying. You've lived all your life with it. You just know. But AGMs just "died" unexpectedly so he advised not doing it.

Sounds like reasonable advice, I suppose.

In the powersports world, AGMs have been used for quite some time primarily, as I understand it, because they are more resistant to failure caused by vibration, and because they can be mounted sideways, upside down, etc. (a trait not needed in most cars).

Me, as I said before, I'll probably just go (or be towed) to the dealership when the time comes. I can understand people's not wanted to spend unnecessarily, but it's not a big deal to me. What gets my goat much more than the cost of battery registration at a dealership is what the mothership charges for different colors on the dash dials, or leather-covered vents, and so forth, and (apparently) folks still pick some of those options.

 

[jeffbtx]

Sounds like reasonable advice, I suppose.

In the powersports world, AGMs have been used for quite some time primarily, as I understand it, because they are more resistant to failure caused by vibration, and because they can be mounted sideways, upside down, etc. (a trait not needed in most cars).

Me, as I said before, I'll probably just go (or be towed) to the dealership when the time comes. I can understand people's not wanted to spend unnecessarily, but it's not a big deal to me. What gets my goat much more than the cost of battery registration at a dealership is what the mothership charges for different colors on the dash dials, or leather-covered vents, and so forth, and (apparently) folks still pick some of those options.

I admit paying for white dials seems extraordinary but it beats the alternative of not being able to see the grey dials in bright sunlight. If only the dials had been back-lit full-time.

 

[wspollack]

...
If only the dials had been back-lit full-time.

Absofreakinlutely!

 

[jzwu]

My experience with AGM batteries is that they do tend to die suddenly. Wet batteries usually give you plenty of time before they finally die.

 

[iconoclast]

Seems like carrying a jump starter may be even more important!

 

[HazelPDX]

I admit paying for white dials seems extraordinary but it beats the alternative of not being able to see the grey dials in bright sunlight. If only the dials had been back-lit full-time.

I couldn't agree more. I have white dials on my 987 and every day when I'm looking at that **** gray dim dial on my Macan I kick myself.

 

[ef1018]

After 526 replies this will probably be lost. I have an outstanding independent repair facility that pretty much only works on German vehicles. They have all the most current equipment to work on these cars.
1. You do not need to go back to the dealer to replace the battery. 2. It is an AGM battery . 3. Several suppliers have them . I am a NAPA advocate , Their batteries are made by East Penn. 4. When replacing you need to keep the circuit powered, so hook up another battery to the booster / jumper posts under the hood. If you un hook the battery you will loose programing in some of the many computers in the car. If that happens it may not start and you'll need to get it towed to a shop that can reprogram them. If you have a 92 AH battery that is what you need to replace it with. The charging system is programed to charge that spec battery. No need or reason to go bigger.
This set up is like most of the German and many others .
I also have an I Teck charger /maintainer set up. If am not using the car for a week or more I plug it in and keep if fully charged. I direct wired the power plug in the rear compartment so it is always hot.

 

[oqjnLu@>@W]

How about connecting the Ctek to the under hood terminals when swapping a battery?

 

[grim]

If you have a 92 AH battery that is what you need to replace it with. The charging system is programed to charge that spec battery. No need or reason to go bigger.

The 92 AH battery is rated 850EN. The 105 AH battery is rated 950 EN. You might appreciate that difference if you live in the snow belt on a cold morning. Programming via PIWIS accomodates either one for the alternator to charge.

 

[jzwu]

How about connecting the Ctek to the under hood terminals when swapping a battery?

I don't think that works. Using jump cables to connect to another car's battery during the swap may work.

 

[Fahrer]

I don't think that works. Using jump cables to connect to another car's battery during the swap may work.

Jump cables work on BMW battery exchanges.

 

[iconoclast]

How about connecting the Ctek to the under hood terminals when swapping a battery?

This has been discussed.
Must be a CTEK or other tender model that has the option for "SUPPLY" power & not merely charge/maintain. I verified this with CTEK.

CTEK Multi US 7002 will work.

But if you have another CTEK, why buy the 7002? Why not spend the $ on a jump starter instead?

JNC 770 will work.

 

[Wolverine]

My experience with AGM batteries is that they do tend to die suddenly. Wet batteries usually give you plenty of time before they finally die.

Is a failing AGM battery less likely to be recognized by a battery analyzer?

 

[Shark]

My experience with AGM batteries is that they do tend to die suddenly. Wet batteries usually give you plenty of time before they finally die.

I have not had that experience. Then again my experience with replacing AGM batteries has been limited to one car, our 2011 X5 50i.

The car came from the factory with an AGM battery despite not having stop/start. Our particular model is notorious for chewing up batteries for a couple of well documented reasons that I won't go into here (unless someone is interested). The car is 9 years old, is on it's third battery, and I'm fully expecting to need a 4th battery soon as the existing one is more than 3 years old.

When the battery starts to go I'll start to get warning messages as shown on the video attached below. Not sure exactly how the warning messages are triggered, but I wonder if the Macan does something similar? Having a sudden dead battery would not be a pleasant experience.

 

[JoeInBucks]

I have not had that experience. Then again my experience with replacing AGM batteries has been limited to one car, our 2011 X5 50i.

The car came from the factory with an AGM battery despite not having stop/start. Our particular model is notorious for chewing up batteries for a couple of well documented reasons that I won't go into here (unless someone is interested). The car is 9 years old, is on it's third battery, and I'm fully expecting to need a 4th battery soon as the existing one is more than 3 years old.

When the battery starts to go I'll start to get warning messages as shown on the video attached below. Not sure exactly how the warning messages are triggered, but I wonder if the Macan does something similar? Having a sudden dead battery would not be a pleasant experience.

The Macan will give you a drive the car more type message if you are doing a lot of shirt trips and then maybe adjust the seats. At least that's when I get the warning message.

Do you use a battery tender of any type on the X5?

 

[Shark]

The Macan will give you a drive the car more type message if you are doing a lot of shirt trips and then maybe adjust the seats. At least that's when I get the warning message.

Do you use a battery tender of any type on the X5?

Thanks. Do you recall exactly what the warning message says?

I do tend to use one of our CTEK's when the X5 (or any of our cars) will be sitting for more than a couple of days.

Here's a Road and Track article describing the specific problems with battery life with the BMW N63 V8 engine. It's interesting even if you don't own one. Seems to me like an example of German over-engineering.

Enginerdy: Why BMW's N63 twin-turbo V8 eats batteries

When cars get complicated, weird things happen. In the search for thrift and power, BMW unwittingly made its N63 a battery killer.

www.roadandtrack.com

 

[wspollack]

...
Here's a Road and Track article describing the specific problems with battery life with the BMW N63 V8 engine. It's interesting even if you don't own one. Seems to me like an example of German over-engineering.

Enginerdy: Why BMW's N63 twin-turbo V8 eats batteries

When cars get complicated, weird things happen. In the search for thrift and power, BMW unwittingly made its N63 a battery killer.

www.roadandtrack.com

That's a fascinating (and pleasantly short) article. Thanks.

 

[grim]

Is a failing AGM battery less likely to be recognized by a battery analyzer?

Not if you know what to look for. Battery analyzers, AFAIK, look at the internal resistance. AGM batteries have lower internal resistance than wet cells. The analyzers know this. For Porsches batteries its measured in EN, just a different type of measure for cold cranking amps. You can research this but AFAIK, when the battery is not fully charged, it sulphates. That hardens over time. The battery then never fully recharges.

3 Ways to Check for a Bad Battery – Tech Tips & Tricks | BatteryStuff

If you think you have a bad battery, but you’re not quite sure, we can help you determine if your motorcycle, RV or ATV battery needs replaced.

www.batterystuff.com

Sulfation decreases the potential to reach a full charge, and it self-discharges the battery quicker than normal. Charging a sulfated battery is like trying to wash your hands while wearing gloves. At this point, charging alone will not restore the battery to a healthy condition. The majority of replacement battery purchases occur when the original battery has reached this point.

In other words, the CCA or EN can be fine but because of sulfation the battery never gets a full charge and discharges quickly. I think thats what they mean by dies quickly. And you can't reverse it. So the analyzer knows the CCA and knows the voltage. It could say it "passed" based on the CCA being good enough but if it never fully charges and quickly discharged, its not good.

 

[Wolverine]

Not if you know what to look for. Battery analyzers, AFAIK, look at the internal resistance. AGM batteries have lower internal resistance than wet cells. The analyzers know this. For Porsches batteries its measured in EN, just a different type of measure for cold cranking amps. You can research this but AFAIK, when the battery is not fully charged, it sulphates. That hardens over time. The battery then never fully recharges.

3 Ways to Check for a Bad Battery – Tech Tips & Tricks | BatteryStuff

If you think you have a bad battery, but you’re not quite sure, we can help you determine if your motorcycle, RV or ATV battery needs replaced.

www.batterystuff.com

In other words, the CCA or EN can be fine but because of sulfation the battery never gets a full charge and discharges quickly. I think thats what they mean by dies quickly. And you can't reverse it. So the analyzer knows the CCA and knows the voltage. It could say it "passed" based on the CCA being good enough but if it never fully charges and quickly discharged, its not good.

Thanks. Makes sense. .