Glass Mat Battery ?
11-21-2014, 01:03 PM
#1
AudiWorld Senior Member
Thread Starter
Glass Mat Battery ?
Today I was talking to a VW tech I know at the dealership and I mentioned all the drained-battery episodes I have had. So, on the topic of batteries, he said that the Phaetona and A8s all came with Glass mat batteries back in 2004. I have never heard of that for A8s or Phaetons...anyone have any info regarding this ? I know Varta makes both types of batteries, but which type was OE ?
I read that one could only use a GMB in a vehicle designed for one because the charging rate of an alternator for a car with a conventional battery would be too high and ruin the GMB. He says the Power Management Module on our cars charges correctly for which ever type to which it is connected. Any of that true ?
What are the advantages of a GMB supposed to be anyhow?
I read that one could only use a GMB in a vehicle designed for one because the charging rate of an alternator for a car with a conventional battery would be too high and ruin the GMB. He says the Power Management Module on our cars charges correctly for which ever type to which it is connected. Any of that true ?
What are the advantages of a GMB supposed to be anyhow?
Last edited by awdinut; 11-21-2014 at 01:38 PM.
11-21-2014, 01:22 PM
#2
AudiWorld Super User
If you look at Varta site, a lot of their talk is now AGM.
Varta is a common OES for the batteries, and is what I got at parts counter with last change out with the coupon I had for a DIY in their parking lot. 
Varta in turn is owned by Johnson Controls, and here is a blurb on what they say: AGM battery technology | Johnson Controls Inc. Varta shows both conventional and AGM on their site if you look.
AGM has been around a long time for boat batteries--kind of in between starter batteries and deep cycle as I recall (I just use the common Type 24 starter there since we don't park boat all day with motor off but still onboard). Also more resistant to vibration, which in a boat/marine environment is no comparison to a car, with a fiberglass hull slamming into chop not infrequently.
FWIW, I tend to look more at reserve capacity, which perhaps the AGMs are getting at anyway. I also noticed in the Audi D3 fitments, the weight moves up and down 10 pounds or more depending on which you look at, and it isn't necessarily that "bigger" is better for the power specs any more.
The W12 in the early years at least is kind of an oddball where if you look at the battery tables it calls for EITHER the smaller or greater length one with no further clear guidance. Mine came with the longer one, or at least that is what went into it when the dealer replaced it the very first year per the service records I got my hands on when I bought it CPO--it was a "house" car used by the dealership owner when it was new.
Varta in turn is owned by Johnson Controls, and here is a blurb on what they say: AGM battery technology | Johnson Controls Inc. Varta shows both conventional and AGM on their site if you look. AGM has been around a long time for boat batteries--kind of in between starter batteries and deep cycle as I recall (I just use the common Type 24 starter there since we don't park boat all day with motor off but still onboard). Also more resistant to vibration, which in a boat/marine environment is no comparison to a car, with a fiberglass hull slamming into chop not infrequently.
FWIW, I tend to look more at reserve capacity, which perhaps the AGMs are getting at anyway. I also noticed in the Audi D3 fitments, the weight moves up and down 10 pounds or more depending on which you look at, and it isn't necessarily that "bigger" is better for the power specs any more.
The W12 in the early years at least is kind of an oddball where if you look at the battery tables it calls for EITHER the smaller or greater length one with no further clear guidance. Mine came with the longer one, or at least that is what went into it when the dealer replaced it the very first year per the service records I got my hands on when I bought it CPO--it was a "house" car used by the dealership owner when it was new.
11-22-2014, 08:12 AM
#3
AudiWorld Super User
Here is a Deka (Made by East Penn Manufacturing Company in Lyon Station, PA) Intimidator Absorbed Glass Mat size Group 95R my son picked up (using two hands as it weighs 64 1/2 pounds) for my A8. It will be going in next weekend as he is away at school and works at a Batteries+ store. My current conventional Deka (only a Group size 49) has been forcing the car in power save mode after only a few days. No need to take a chance with Winter coming fast.
11-22-2014, 10:57 AM
#4
AudiWorld Senior Member
Thread Starter
what about charging rate...
Here is a Deka (Made by East Penn Manufacturing Company in Lyon Station, PA) Intimidator Absorbed Glass Mat size Group 95R my son picked up (using two hands as it weighs 64 1/2 pounds) for my A8. It will be going in next weekend as he is away at school and works at a Batteries+ store. My current conventional Deka (only a Group size 49) has been forcing the car in power save mode after only a few days. No need to take a chance with Winter coming fast.
I am searching for a way(s) to end my battery problems, so I have been curious about the AGM batteries. The VW tech I mentioned said that I need to lock my car anytime I am not in the car because that is the only way to put the car to sleep and cut the drain on the battery. And that would fit with my experience this week: I do not lock my car when it is in my girlfriend's driveway, and I spent two 8 hour days working on her house this week and on the third day when I went for supplies my battery was dead (9.5V). And I only live 5 minutes away so the car had not had a chance to charge the battery after all tha sitting un-locked. So I will lock my car at all times now and see if that prevents future incidents.
11-22-2014, 01:09 PM
#5
AudiWorld Super User
Basically just a (big) battery in the Audi N. America case...but just for laughs...
Better to replace it than sweat it too much. 80-90%, batteries are batteries. If you like the AGM description, go for it.
My test is simple, twice let down where I didn't cause the issue with my own stupidity (lights on, ran electronics way too long doing VAG COM w/ ignition on, etc.), and time to replace. Sounds like you are there worn down wise, and winter is upon us. If you want more juice, focus on reserve capacity and the 49/95R choice. More specific to your experiences, I would expect it isn't that the car needs to be locked to put it to sleep. Or...that you need a witch doctor to shake some salt on the hood, or a priest to bless it, or many other stories. Simply, your battery is just about crapped out, and maybe a cell is fried too. It can barely hold a charge, and the power management system is cutting in a lot to eliminate the auxiliaries and try to allow you to keep starting.
For your obscure Phaeton reference, I think what you may be running into is an even further oddity with those. In some applications like a V10 TDI and maybe others, they actually had two batteries--a conventional "wet" battery for starting on the drivers side, AND an AGM for convenience electronics and such on the other side. Frankly, typical German ridiculous overcomplexity to me. Phaetons are also total weight pigs, way more than D3's. Nothing like carrying around 2 batteries just for the heck of it to throw in another 60 pounds of pork, and never mind it is pretty high up and outside the wheelbase as far as polar moment type analytics. Meanwhile, in the real world in the good old US of A (and Canada), we typically face far harsher weather at the extremes than they do--outside of Scandinavia or say, headed toward Russia...--so I'm perfectly comfortable with US thinking and designs in general for vehicle battery storage. Read on though for some other market deltas that may also drive the Euro differences.
From the Audi D3 battery the dealer sold me last summer and that has a 2013 inventory date on it (as in, "current"), from the absence of the reference I would say it is a non AGM. The part number ends in DL. But, I think Audi also sells AGMs side by side too. I think those end with CE. The full part number for reference in mine is 000 915 105 DL. Here's a link to a parts listing where you can see various choices, and more importantly the capacities involved for the Audi spec. ones: AUDI A8/S8 QUATTRO [A8Q] (USA) 2004: ELECTRICS: 91500. BATTERY; BATTERY MOUNTING; FOR SPECIAL ARMOURED VEHICLE Don't know why the listing says "armoured" so much; it seemed to be the choice for any and only the mounting stuff varied. Euro EKTA simplifies it to just two choices, the DK and the DL suffixes for the smaller and larger sizes: Audi - A8Q - 2006 - Electrical Teile Katalog (Pats Catalog)
On your AGM specifics, here is a West Marine article on battery tech, and you can read down to where it distinguishes between flooded and AGM for the relevant benefits: Selecting a Marine Storage Battery | West Marine Again, boat applications are often more challenging than cars--can sit for months or a year, may start big old American heavy iron, can be draining while anchored for even days, can take really hard hits from chop right through the hard hull--like huge pot holes hundreds of times over, etc.
Applied to a D3 in North America, and why I think it's kind of esoteric/doesn't really matter, is that technically North American D3's don't even have some of the Euro tweaks that can REALLY drain a battery compared to what you are thinking. They aren't diesels, so don't have the mega surge of a glow plug set up. They don't have supplemental full on electric heaters (not just the wimpy Piech underfloor fruh fruh stuff that we can all see burned out in the VCDS scans). Except for the W12 they don't have the rear seat video that could be run for long periods, including a feedback projection to the MMI screen when stationary. They don't have the concept of leaving on the road side parking lights for extended periods to mark the vehicle's roadside presence, etc. Euro A8s are also essentially limos, and use of drivers by business exec's in Europe and Germany is common--one of the big reasons they have the "L" art down so well. Well, that means "Hans" the driver can be sitting around the car for hours killing time, hence again more criticality in battery storage and recovery than your typical U.S. application. If Hans runs Herr Geschaeftfuehrer's spiffy Kampfwagen battery down playing too much ELP or Auf der Autobahn or whatever, not a good day...
Net buy a battery. Pick the flavor. If AGM sounds great, fine. If you like a given brand, great. If its a coupon deal, great (how I got to the dealer actually...). If you love Sears, great. If you like Costco or Wallyworld, great. If you want to buy American, great. If you want more info on typical life, pull out the annual Consumer Reports articles (that cover some brands and only common sizes). Frankly, I think you could drop a Group 24 most common battery on Earth and it would still do fine, other than fastening it down right, dealing with the vent tube, and the terminals likely being wrong end positioned. More seriously, focus on the reserve capacity for energy storage if you worry about that. You actually aren't turning a very big motor by old V8 American standards, nor a TDI nor a W12, so cold cranking of any Audi spec battery is going to serve you fine. And you're not running 2000+ watts in the trunk either. As Mister Bally mentioned, if you have the "junior" Audi A8 version and you want some more reserve--and road hugging weight too--buy the "big boy" size.
Finally, if you want to do a deep dive on Audi D3 Electrical, there was a self study guide on it published back when the car came out. I have the US one, but on line only found the similar British one. I think if you look through the whole charging section, you will probably conclude the supposed D3 secret sauce is in the energy management system, not the battery. They really just seem to think of it as basically what it is in this application--a pretty simple energy storage medium. Try pasting this search string into Google, and then picking the choice for the 287 publication: self study programme 287 audi A8 site:forum.a8parts.co.uk It was a pdf reference, and I couldn't get at the link directly on my Mac.
My test is simple, twice let down where I didn't cause the issue with my own stupidity (lights on, ran electronics way too long doing VAG COM w/ ignition on, etc.), and time to replace. Sounds like you are there worn down wise, and winter is upon us. If you want more juice, focus on reserve capacity and the 49/95R choice. More specific to your experiences, I would expect it isn't that the car needs to be locked to put it to sleep. Or...that you need a witch doctor to shake some salt on the hood, or a priest to bless it, or many other stories. Simply, your battery is just about crapped out, and maybe a cell is fried too. It can barely hold a charge, and the power management system is cutting in a lot to eliminate the auxiliaries and try to allow you to keep starting.
For your obscure Phaeton reference, I think what you may be running into is an even further oddity with those. In some applications like a V10 TDI and maybe others, they actually had two batteries--a conventional "wet" battery for starting on the drivers side, AND an AGM for convenience electronics and such on the other side. Frankly, typical German ridiculous overcomplexity to me. Phaetons are also total weight pigs, way more than D3's. Nothing like carrying around 2 batteries just for the heck of it to throw in another 60 pounds of pork, and never mind it is pretty high up and outside the wheelbase as far as polar moment type analytics. Meanwhile, in the real world in the good old US of A (and Canada), we typically face far harsher weather at the extremes than they do--outside of Scandinavia or say, headed toward Russia...--so I'm perfectly comfortable with US thinking and designs in general for vehicle battery storage. Read on though for some other market deltas that may also drive the Euro differences.
From the Audi D3 battery the dealer sold me last summer and that has a 2013 inventory date on it (as in, "current"), from the absence of the reference I would say it is a non AGM. The part number ends in DL. But, I think Audi also sells AGMs side by side too. I think those end with CE. The full part number for reference in mine is 000 915 105 DL. Here's a link to a parts listing where you can see various choices, and more importantly the capacities involved for the Audi spec. ones: AUDI A8/S8 QUATTRO [A8Q] (USA) 2004: ELECTRICS: 91500. BATTERY; BATTERY MOUNTING; FOR SPECIAL ARMOURED VEHICLE Don't know why the listing says "armoured" so much; it seemed to be the choice for any and only the mounting stuff varied. Euro EKTA simplifies it to just two choices, the DK and the DL suffixes for the smaller and larger sizes: Audi - A8Q - 2006 - Electrical Teile Katalog (Pats Catalog)
On your AGM specifics, here is a West Marine article on battery tech, and you can read down to where it distinguishes between flooded and AGM for the relevant benefits: Selecting a Marine Storage Battery | West Marine Again, boat applications are often more challenging than cars--can sit for months or a year, may start big old American heavy iron, can be draining while anchored for even days, can take really hard hits from chop right through the hard hull--like huge pot holes hundreds of times over, etc.
Applied to a D3 in North America, and why I think it's kind of esoteric/doesn't really matter, is that technically North American D3's don't even have some of the Euro tweaks that can REALLY drain a battery compared to what you are thinking. They aren't diesels, so don't have the mega surge of a glow plug set up. They don't have supplemental full on electric heaters (not just the wimpy Piech underfloor fruh fruh stuff that we can all see burned out in the VCDS scans). Except for the W12 they don't have the rear seat video that could be run for long periods, including a feedback projection to the MMI screen when stationary. They don't have the concept of leaving on the road side parking lights for extended periods to mark the vehicle's roadside presence, etc. Euro A8s are also essentially limos, and use of drivers by business exec's in Europe and Germany is common--one of the big reasons they have the "L" art down so well. Well, that means "Hans" the driver can be sitting around the car for hours killing time, hence again more criticality in battery storage and recovery than your typical U.S. application. If Hans runs Herr Geschaeftfuehrer's spiffy Kampfwagen battery down playing too much ELP or Auf der Autobahn or whatever, not a good day...
Net buy a battery. Pick the flavor. If AGM sounds great, fine. If you like a given brand, great. If its a coupon deal, great (how I got to the dealer actually...). If you love Sears, great. If you like Costco or Wallyworld, great. If you want to buy American, great. If you want more info on typical life, pull out the annual Consumer Reports articles (that cover some brands and only common sizes). Frankly, I think you could drop a Group 24 most common battery on Earth and it would still do fine, other than fastening it down right, dealing with the vent tube, and the terminals likely being wrong end positioned. More seriously, focus on the reserve capacity for energy storage if you worry about that. You actually aren't turning a very big motor by old V8 American standards, nor a TDI nor a W12, so cold cranking of any Audi spec battery is going to serve you fine. And you're not running 2000+ watts in the trunk either. As Mister Bally mentioned, if you have the "junior" Audi A8 version and you want some more reserve--and road hugging weight too--buy the "big boy" size.
Finally, if you want to do a deep dive on Audi D3 Electrical, there was a self study guide on it published back when the car came out. I have the US one, but on line only found the similar British one. I think if you look through the whole charging section, you will probably conclude the supposed D3 secret sauce is in the energy management system, not the battery. They really just seem to think of it as basically what it is in this application--a pretty simple energy storage medium. Try pasting this search string into Google, and then picking the choice for the 287 publication: self study programme 287 audi A8 site:forum.a8parts.co.uk It was a pdf reference, and I couldn't get at the link directly on my Mac.
Last edited by MP4.2+6.0; 11-22-2014 at 01:31 PM.
11-22-2014, 02:39 PM
#6
AudiWorld Senior Member
Thread Starter
Wow, that was quite a monograph...thanks for expending all that time ! The battery I have at present is an Energizer brand from Sam's, group 49, and is only 2 years old, having been replaced under warranty for the premature demise of the previous one.
And having had low battery a couple times this summer (again the 'un-locked car scenario could have been the reason) I removed the battery and ahd Sam's shop and my mechanic check the battery and all cells were good.
I designed my DVD system with a master switch so there is never a draw except when enabled, the fridge is on only on an as-needed-basis,the illuminated sills are wired into the footwell light circuit so thres a limited time draw, I designed the turning light circuits to feed from the headlights so they cant draw if the headlights are not on, and otherwise my A8 is , electrically speaking, stock.
So, I will give the 'locked door theory' some time and we'll see what happens.
And as to the VW tech's notion that our NA A8s came with an AGM battery, I have not read any posts here that would support that.
And as to the charging rate question...the article I read cited possible burn up, burn out, explosion. Are any of you using AGM batteries and no charging issues ? Because I liked what I read as far as the qualities unique to AGMs and I would get one next time if that business about the cars system needing to have been designed for them as on some newer vehicle models.
And having had low battery a couple times this summer (again the 'un-locked car scenario could have been the reason) I removed the battery and ahd Sam's shop and my mechanic check the battery and all cells were good.
I designed my DVD system with a master switch so there is never a draw except when enabled, the fridge is on only on an as-needed-basis,the illuminated sills are wired into the footwell light circuit so thres a limited time draw, I designed the turning light circuits to feed from the headlights so they cant draw if the headlights are not on, and otherwise my A8 is , electrically speaking, stock.
So, I will give the 'locked door theory' some time and we'll see what happens.
And as to the VW tech's notion that our NA A8s came with an AGM battery, I have not read any posts here that would support that.
And as to the charging rate question...the article I read cited possible burn up, burn out, explosion. Are any of you using AGM batteries and no charging issues ? Because I liked what I read as far as the qualities unique to AGMs and I would get one next time if that business about the cars system needing to have been designed for them as on some newer vehicle models.
11-22-2014, 03:01 PM
#7
AudiWorld Super User
I am not at all concerned about installing it in my A8. Will let everyone know if I have any issues though. Note how the label on mine says "Starting and cycling" which is the best possible scenario.
Awdinut, I have posted this before where my long gone '87 5000CS quattro started to drain completely every so often at random. In the morning, completely dead. I would recharge the good battery and sometimes fine and other times dead. Left it at the airport for several days and no problem but one time it was dead after working at the office. Fortunately, it had a stick so easy to push start it.
Finally, after verifyng no electrical consumers were present I went out to the car at midnight after letting it cool down for about six hours. I placed my hand on the alternator and it was toasty warm vs. everything else. The alternator indicator lamp functioned properly and the useless "Auto-Check" system did not indicate a fault. The heat was from a leaky diode in the alternator that would sometimes latch in a shorted mode draining the battery. I replaced the alternator and all was well again.
Awdinut, I have posted this before where my long gone '87 5000CS quattro started to drain completely every so often at random. In the morning, completely dead. I would recharge the good battery and sometimes fine and other times dead. Left it at the airport for several days and no problem but one time it was dead after working at the office. Fortunately, it had a stick so easy to push start it.
Finally, after verifyng no electrical consumers were present I went out to the car at midnight after letting it cool down for about six hours. I placed my hand on the alternator and it was toasty warm vs. everything else. The alternator indicator lamp functioned properly and the useless "Auto-Check" system did not indicate a fault. The heat was from a leaky diode in the alternator that would sometimes latch in a shorted mode draining the battery. I replaced the alternator and all was well again.
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11-22-2014, 03:57 PM
#8
AudiWorld Senior Member
Thread Starter
It would be another step in the scientific method but
I am not at all concerned about installing it in my A8. Will let everyone know if I have any issues though. Note how the label on mine says "Starting and cycling" which is the best possible scenario.
Awdinut, I have posted this before where my long gone '87 5000CS quattro started to drain completely every so often at random. In the morning, completely dead. I would recharge the good battery and sometimes fine and other times dead. Left it at the airport for several days and no problem but one time it was dead after working at the office. Fortunately, it had a stick so easy to push start it.
Finally, after verifyng no electrical consumers were present I went out to the car at midnight after letting it cool down for about six hours. I placed my hand on the alternator and it was toasty warm vs. everything else. The alternator indicator lamp functioned properly and the useless "Auto-Check" system did not indicate a fault. The heat was from a leaky diode in the alternator that would sometimes latch in a shorted mode draining the battery. I replaced the alternator and all was well again.
Awdinut, I have posted this before where my long gone '87 5000CS quattro started to drain completely every so often at random. In the morning, completely dead. I would recharge the good battery and sometimes fine and other times dead. Left it at the airport for several days and no problem but one time it was dead after working at the office. Fortunately, it had a stick so easy to push start it.
Finally, after verifyng no electrical consumers were present I went out to the car at midnight after letting it cool down for about six hours. I placed my hand on the alternator and it was toasty warm vs. everything else. The alternator indicator lamp functioned properly and the useless "Auto-Check" system did not indicate a fault. The heat was from a leaky diode in the alternator that would sometimes latch in a shorted mode draining the battery. I replaced the alternator and all was well again.
unfortunately the alternator in these cars is not accessable. If it were, I would like to do a test of the amp output of my alternator, just to eliminate another possibility. It puts 14 volts back to the battery but I dont know what amperage.
11-22-2014, 05:55 PM
#9
AudiWorld Member
I just replaced my battery with an AGM from advanced auto parts found a $50 coupon so it was 151 out the door. Have not had any issues. Measuring blocks in VCDS will tell you battery condition.