# New battery coding (fleece vs AGM- binnary)



## AlexanderC2 (Dec 27, 2020)

How can I check if the service centre has properly coded the new battery in to the cars system? (via OBDeleven)

And if they somehow didnt, how can I do it myself? (via OBDeleven)


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## kevin#34 (Jan 8, 2019)

i don't know how it works with OBD 11 (I use VCDS), but basically you need to check if the BEM sticker code, battery maker name and battery A/h capacity match with what is currently coded in _61 battery regulation_ module


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## AlexanderC2 (Dec 27, 2020)

I found it searching around the OBDeleven forum. It can be done! 

HOWEVER
I have another question. You need to chose the battery type: *fleece or AGM-binary?*

Which one do I select for my VARTA 80AH D+ AGM Sliver battery?

Internet cant produce a definitive answer. *Some say fleece some AGM binnary...*  :?:


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## kevin#34 (Jan 8, 2019)

if your battery is AGM type, I would select AGM


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## chelspeed (May 6, 2017)

https://www.audizine.com/forum/showthre ... y-AGM-quot

Opinion on the above thread is that fleece is the right answer. Personally I doubt if there is much difference between AGM and fleece as the electrode materials and the electrolyte chemistry appear to be the same just the construction method is different. Now if you were changing to LiPo for example I'd be a lot more concerned about getting the right settings.

Still thanks for raising it, if I'd changed my battery it would never have occurred to me I needed to change settings. I've learnt something about modern lead acid batteries I didn't know. Every day's a school day.


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## AlexanderC2 (Dec 27, 2020)

There are a lot of people saying one way or another. But I get the general feeling that fleece is the way to go. Although some have set their batteries to AGM binary, they never had any adverse effects.

I will set mine back to fleece and set manufacturer to VAO. Might as well do it right 

Yes you need to recode the battery apparently if: the technology changes or the capacity (which in my case went from 70Ah to 80Ah)


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## kevin#34 (Jan 8, 2019)

you have to code a (new) battery even if it is the same brand, technology and A/h capacity of the previous one, otherwise it will not be charged at its full potential
regarding the AGM/fleece matter, did you check how the old battery was coded?


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## AlexanderC2 (Dec 27, 2020)

kevin#34 said:


> regarding the AGM/fleece matter, did you check how the old battery was coded?


It was set to *fleece.*

However, I have no idea what: type/technology, brand or capacity; was the old battery. So I didnt know if I was to use the same data from before.

According to battery testers the old one was at 60% battery health.

Thats why I changed it.

I managed to code the battery with new serial number, added manufacturer (3 letter) and updated the capacity from 70 to 80Ah.


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## kevin#34 (Jan 8, 2019)

AlexanderC2 said:


> However, I have no idea what: type/technology, brand or capacity; was the old battery. So I didnt know if I was to use the same data from before.


didn't check the old batteri itself?


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## AlexanderC2 (Dec 27, 2020)

kevin#34 said:


> didn't check the old batteri itself?


No I didn't. I only knew it was old and in trash health. Left the mechanic to replace it with new one.

But if the old adaptation is to be trusted. The old battery was: 70Ah JCB. Thats all I know.

Does not matter now. I managed to code the new battery and thanks to all of you I did it correctly. Today I will just hop in to change the battery type back from AGM-binary to Fleece.


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## AlexanderC2 (Dec 27, 2020)

UPDATE:
Changed it back to fleece. I have been hearing a lot of people saying that fleece is AGM.

So there is that.

Sidenote:
Many problems on this car are related to bad battery and dropped voltages. So having a good condition car battery on this car does save you a headache.


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## kevin#34 (Jan 8, 2019)

sure, and a proper coding of a new battery is vital too (for the battery itself)


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## chelspeed (May 6, 2017)

kevin#34 said:


> sure, and a proper coding of a new battery is vital too (for the battery itself)


Do you know why or how? Does the different coding change the voltage out of the alternator, the amount of time it charges for or what? Just interested. in the old days an alternator just charged at a fixed voltage (depending on revs) and the type or size of battery it was connected to didn't matter. So what's changed?


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## AlexanderC2 (Dec 27, 2020)

chelspeed said:


> kevin#34 said:
> 
> 
> > sure, and a proper coding of a new battery is vital too (for the battery itself)
> ...


From what my mechanic told me. Coding a new battery is important because the system that managed recharge rate via alternator constantly calculates and takes in to account batteries: capacity, technology (AGM, Wet...) and the batteries health.

Taking it all in to consideration it schedules and dictates how much and often the battery is charged.

If the system still thinks that it's working with old battery (like in my case 70Ah with 60% of battery health). It will work double hard to keep it charged as much as possible. When in reality you have new 80Ah with 100% health. You can basically damage the battery fairly quickly by overcharging it.

They say to code the battery just change the appropriate capacity (if the new battery is different cap) and to change the serial number at least by 1 number. So the system acknowledges that its a new new battery.

Battery technology should be the same mostly. These start stop cars need AGM battery for the most part. So you will already most likely buy a replacement battery of AGM technology.

Kevin can add or correct me on this


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## kevin#34 (Jan 8, 2019)

100% correct
the recharging system on latest cars (TT included) is quite sophisticated
changing/increasing the serial number basically says to system that the battery is a new battery, obviously setting the correct battery A/h and technology is fundamental too


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## macaddict111 (Jun 13, 2018)

If you've put in an AGM battery, it should be set to *fleece*. Apparently this is a "bad translation" of the fleece/wool-looking material in AGM batteries and the German word used for them. More importantly, and leading to my next thought, the resting voltage of the battery when set to "fleece" is 12.8, which is exactly what you want for AGM.

Keeping a battery at 14V like in the old days is terrible for batteries, especially newer designs like AGM. Most modern cars (like any modern Audi) have a "accessory mild hybrid" system in that the ECU tries to only run the alternator and recharge if the driver is braking or coasting (aka sort of like regenerative braking). This means the alternator isn't loading the engine when trying to accelerate, which makes things faster and emissions lower. It also means the power needed to restart the engine after start/stop is basically "free" energy gained during braking when you're wasting it anyway.

The important part to maximize this process, is that the ECU needs to know the state of charge of the battery at all times to keep from under or over charging it. This depends on the overall Ah capacity of the battery and its age (hence coding overall capacity and resetting the "age" timer with a new serial number). Additionally, different battery chemistries need to be held at different resting voltages. Normal flooded lead acid like to be held at 12.6 V. AGM needs 12.8 V. If you switch from a flooded cell to an AGM battery and don't change the coding, the new AGM will always be undercharged at 12.6 V, which can in many cases literally half the overall life of the battery.


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## AlexanderC2 (Dec 27, 2020)

Superb explanation macaddict111 

I would just like to add that I was told that this car (and similarly other "electricity heavy" models) really suffer and go haywire when the car battery is not in good shape (capacity, performance and battery health).

Completely not unheard of that the DSG learning program keeps forgetting old parameters and has to relearn your DSG habits & other stuff each time the battery drops well bellow the allowed power threshold. Basically if you have old bad battery and keep getting start stop activated extensively (city traffic basically).
Not to mention 100 different errors that pop up randomly and disappear due to low battery voltage.


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## TomiSharpe (May 31, 2021)

It can be done all by yourself, but make sure to ask professionals for advice or opinion! Double-check everything as you go along the process of coding an Audi battery. You may either solve the problem or just worsen it, you know.


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