'10Q7TDI_Prestige'

If anyone has an H8 AGM battery BEM code, please share it here as that is the most common replacement size/type from the aftermarket. There were no H9 AGMs available when mine died, so got next best option, H8 AGM.

Just realized I used a BEM code sourced from a wet-cell H8 battery (Duralast Gold H8), and not the AGM version of the H8 battery. My understanding is the battery mgmt may not be as 'aggressive' in charging/maintaining the AGM battery due to my coding it as a wet-cell battery. I know this is definitely true of the newer electronic battery chargers that have a 'standard/wet-cell' vs. AGM battery setting/switch, as the AGM batteries can handle a higher amp charge rate safely. I welcome any knowledge around this subject so far as the car's charging mgmt system is concerned.

Here are the stats on the battery I sourced: Diehard Platinum H8-AGM, 900 Cranking Amps, 160 min Reserve, 95 Amp Hours.

Blackfunk

My understanding is that you can reuse your existing serial number and simply change the last digit to 'trick' the system into believing that there's a new battery installed. That at least has been internet folklore for sometime now. I'll be changing my battery either this afternoon time permitting or Sunday so I may be back here asking the same question later on. Best of luck.

Panzer A4

Here's some info on the code and how to "fake" a new one.
https://www.audizine.com/forum/showt...acement-Coding

Blackfunk

This is the best I've found thus far

drjonez

Some more BEM Code info:

https://www.audizine.com/forum/showt...perage-ratings

dreadlocks

IIRC an H8 AGM should be 92AH
From: https://upgrademyaudi.net/tutorials/...-battery-vcds/

51Ah – 8K0915105J / 000915105BB / 000915105DC
60Ah – 4F0915105 / 8K0915105G / 000915105DD
61Ah – 8K0915105H / 000915105AD / 000915105DE
70Ah – 4F0915105A / 8K0915105C / 000915105DF
72Ah – 8K0915105B / 000915105AF / 000915105DG
80Ah – 4F0915105B / 8K0915105D / 000915105AG / 4FD915105 / 8KD915105 / 000915105DH
95Ah – 4F0915105C / 8K0915105E / 000915105AH / 000915105DK
110Ah – 4F0915105D / 8K0915105F / 000915105AK / 8KD915105A / 000915105DL
68Ah – (AGM) 7L0915105 / 000915105CC
75Ah – (AGM) 3D0915105H / 000915105CD
92Ah – (AGM) 4F0915105E / 000915105CE
105Ah – (AGM) 4L0915105 / 000915105CF
115Ah – 4H0915105 / 000915105DM

Part number / Serial number

colezy9

Would I be alright using the 92Ah AGM code? I bought an aftermarket (Energizer / Johnson Controls) AGM battery from Costco. It's 95aH, H8, 900 CCA battery.

dreadlocks

yea

Blackfunk

In the interest of settling this argument once and for all, I'll be changing the battery in my B8 S4, some day this week - expected delivery is this coming Thursday.
Early last I replaced the battery in my 15 Q7 which was still on the original battery with https://www.autozone.com/batteries-s...cca/229889_0_0 Duralast H9 950CCA 140min reserve time 100Ah battery and did not code it when I changed it on the Q7. The battery in my 2012 S4 was replaced back in February 2014 (I believe) while under warranty due to some weird behavior - main cluster would not light up, rearview camera would not turn on etc - so its been about 8 years on the same battery (hell of a good run) car only has 54k miles so its not been driven a lot.

I ordered the same battery and I will code this new battery to the car and should hopefully be able to tell if there's a significant difference in the overall performance on either platform due to coding vs none coding. Granted not an apples to apples comparison but potentially a worthy experiment.

dreadlocks

It's an easy test, I've done it and I assure you it's required.. fire up the car and check the voltage before and after coding, should be ~14.6v.. but it won't be with the old battery coding, it'll be dramatically undercharging it until you code the battery than bam it'll instantly jump to >14VDC

VCDS will show you the voltages too so you don't even need to measure it directly.. I dont remember the numbers exactly I was seeing but IIRC it was at least a full volt under spec when I did mine.

Ive been putting the date on the battery into the serial number so I can check the date later without pulling the seat out.