AGM Battery Charging: How To & Tips

Hello everyone,
nachdem ich die ganzen Batteriethemen hier gelesen habe, hab ich auch mal geschaut, was bei mir verbaut ist. Es ist eine 68AH Varta AGM lt. Stickers.
However, in the battery management system (STG 61), a conventional flooded battery is coded instead of an AGM battery, and this is set by the factory. Otherwise, the battery code appears to be fine.
What I noticed in the measurement data blocks was that the status for battery identification is currently showing as "inactive."

Can someone tell me why it's not encoded as AGM?

Best regards.
Dirk.

Hello Dirk,

Similarly, the software doesn't always have to be perfect, just like the displayed coding information doesn't necessarily have to be accurate.
Either a different battery was installed than intended, or the coding was not adjusted/set correctly, or the coding information is incorrect in this regard.

Whether this is relevant for the daily operation and lifespan of the battery is something that battery specialists need to assess.

A comparison with the battery in the 8PA revealed that it is also an AGM type, but VCDS displays "wet cell battery." It was not possible to code it as an AGM battery, which suggests that the coding information may need to be adjusted.

Best regards, Rainer.
Sure, here is the translation of the text from German to English:

"PS: Background"

I hope this helps! Let me know if you have any other questions.
Okay, I'm ready. Please provide the German text you want me to translate into English. Just paste it here, and I will give you the translation.

Hello!
I need to follow up on something here:
Since I absolutely avoid the start-stop function and am not a fan of short trips, there's actually no reason for me to resort to an (expensive) AGM battery as a replacement, right?

If I now switch to a standard lead-calcium battery, what exactly do I need to specify regarding the correct charging voltage?


Address 61: Battery Management (J840)
Label file: RKS\1K0-907-534.clb
Part number SW: 8P0 907 534, HW: 1K0 907 951.
Component: Battery control unit H33 0302.
Serial number: 210610F2002514
Encoding: 030B085A
Operating number: WSC 06314 000 00000
VCID: F4E2FF9957C078BE00B-80A1



Subsystem 1 - Part number SW: 1K0 915 181 E, HW: 1K0 915 181 A.
Component: J367-BDM H07 0140

No error codes found.


Is the battery management system integrated into the gateway, and is that small box located at the ground terminal part of that subsystem? Or is there actually a separate control unit specifically for battery management? Does anyone know where this would be located in an Audi A3 8PA?

brezelmann01 wrote:

Since I absolutely avoid the start-stop function and am not a fan of short distances either, there is actually no reason for me to resort to an (expensive) AGM battery in case of replacement, right?

Correct.

Quote:

However, if I switch to a standard lead-calcium battery, what exactly do I need to specify regarding the correct charging voltage?

I suspect that it probably doesn't matter much.
Many newer "standard" batteries are already approved for use with a voltage of 14.8V.
As a precaution, take a battery whose cells can still be opened (see https://community.dieselschrauber.org/en/viewtopic.php?t=27322).
Then you can at least refill the water, in case it tends to become overloaded and releases too much gas.
You obviously can't repair accelerated grid corrosion caused by an excessively high charging voltage this way.

There might be a way to find such a battery.
However, I think it would be more sensible to leverage the capabilities of the internal network and code accordingly.

"Hey Rainer, can you tell me something about this? Or what information do you need from me?"

Hello Brezelmann,

Just go into the coding of your battery management system and see what settings are available there.

Best regards, Rainer.

Hi!

This morning I checked. So, I can code for AGM, wet cell battery (current setting as shown in post #1), or a third option (which I've just forgotten).
"By the way, I can encode the battery type to AGM without any problems, but the ignition must be turned on for that! Reading the data is also possible without turning on the ignition. Are there already any findings about whether there are vehicles with this battery system that are actually encoded as having an AGM battery?"

Best regards,

Hello,

Let me check what the A3 is displaying; that previous post is from 2012. Are you using the latest VCDS-RKS version 12.12.2?

Best regards, Rainer.

Yes. Version 12.12.2, data as of 20140225.


Please check the energy throughput and aging of the A3 battery as well. I'd be interested to know more about that. Also, what is the difference between charge-related aging and performance-related aging?


Thank you very much so far!

Hello,

The A3 is still coded to use a wet battery and does not accept AGM batteries.

Charge-related aging: This is how much energy the battery can store.
Ageing related to performance: This is the maximum starting current that the battery can deliver.

Best regards, Rainer.

Hi!

You're welcome!
Perhaps I will create logs of the charging voltage/current, encoded for both AGM and flooded batteries. Maybe we can identify a difference between the two encodings.

How old is the battery you showed me?

brezelmann01 wrote:

How old is the battery that you showed me?

The battery is from the beginning of 2010, so it's a little over 4 years old.

Hello everyone!

Today, I drove the car twice. Once with the original factory coding for a wet cell battery, and once after being recoded for an AGM battery.
I can't see any difference between the two logs. Both are perfectly stable at 14.2 - 14.3 volts (at an outside temperature of 25°C). I might try repeating this test around 15-20°C to see if I can detect a difference. Perhaps the temperature compensation is interfering with the readings at these temperatures.

Hello,

I have since driven a few more times with both the wet-cell battery and the AGM battery. I can't detect any difference in behavior between the two types of batteries, even at different temperatures. After starting the engine, the voltage quickly rises to 14.7 volts.

After that, I looked for some scans of the A3 in this forum.
My devices, based on my hardware and software versions, seem to be consistently coded as "Wet," while the newer ones are coded as AGM (see below).

Since I almost exclusively drive long distances, I'd like to skip the expensive AGM battery when it needs replacing and opt for a standard lead-calcium (Pb-Ca) battery instead. However, the correct charging voltage would then be important. And 14.7V is definitely too high. With Varta, you can find values of 14.8V for AGM batteries and 14.4V for "normal" batteries.
How is an A3 coded from the factory without an AGM (Automatic Gearbox Module)?

Does anyone know about battery coding and how it depends on hardware and software versions?


"Own scan:"
Address 61: Battery Management (J840)
Label file: RKS\1K0-907-534.clb
Part number SW: 8P0 907 534, Part number HW: 1K0 907 951.
Component: Battery control unit H33 0302.
Serial number: 210610F2002514
Encoding: 030B085A
Company No.: WSC 06314 000 00000
VCID: F4E2FF9957C078BE00B-80A1


Foreign can:
Address 61: Battery Management (J840)
Label file: DRV\1K0-907-534.clb
Part number SW: 8P0 907 534, hardware number: 1K0 907 951.
Component: Battery management system H43 0311.
Serial number: 100411F1002616.
Encoding: F30B185A
Operating number: WSC 06314 000 00000
VCID: F4EC2AE957B594BE00B-80A1
Subsystem 1 - Part number SW: 1K0 915 181 F, HW: 1K0 915 181 A.
Component: J367-BDM H07 0150
No error codes found.

Hello everyone,

I've read the posts about battery coding and now I want to access this control unit (module) myself using VCDS (STG 61). I can find the control unit, but I can't access it. What could be the reason for that?

I drive a 2013 Audi A3 8VA 2.0 TDI quattro.
I have a start-stop system and an AGM battery.
Could it be that I don't actually have this control unit? Or is there a trick to accessing it?

I suspect that my battery needs to be replaced, and I'm currently researching how to do it myself and what adjustments I need to make.
But the internet hasn't been very helpful to me in this regard, so I'm turning to you now.

Best regards from Gera, Thuringia.

Marcel.

Hello,


The 61 might be integrated into your 09 system.

Regards,
Pretzelman.