Battery change I just wanna make sure I don't mess nothing up anyone got like advice or steps on how I should change my battery I'm pretty sure my battery Is bad I got a new one and a 4amp charger/ maintainer but not sure if that's sufficient

 

Make sure to get the correct size battery and code it in correctly. AutoZone Duralast H9-DLG is the OEM Varta one relabeled as a Duralast. Even has the correct BEM code on it that you’ll need to code into the car’s Energy management module. Also, don’t waste money on an AGM type battery thinking it’s an ‘upgrade’. The battery management system is not designed to work with them.

 

I am “scanning” forums for the same reason.

My car is 2009 Audi A8 4.2L V8 A/T Quattro L Sedan

Vehicle Battery swap /110AH/520 amp battery.

Vehicle Battery. Part Number: 000915105DL

Correct size is important. Date of production is important. Charge it before you install it.

NEW Battery must be encoded in the control unit for power management

In US Advance auto sells for my car DieHard Gold Battery: H9 Group Size, 950 CCA, 1185 CA, 110 Amp Hour Capacity, Maximum Starting Power.

I am in Canada. First, I went to a local Audi Dealer. From My VIN# they offered me Varta battery AGM for $410.00 CAD plus tax and about $200.00CAD for installation and coding. $700.00-$800.00 Total. I did more investigation and found out that AGM would be incorrect battery since my car original came only with LEAD – ACID battery -a conventional wet or flooded battery.

Next, I went to a local auto parts store, and they sold me H8 size flooded battery EverStart dated April 2024. Good battery and “fresh” for $230.00 CAD, but wrong size, so I returned it. I did more research and went to other local store “Quest…something” . They ordered battery for me NEW DieHard H9 L6 95R Group Size, 950 CCA, 1185 CA, 110 Amp Hour Capacity, LEAD – ACID battery. Good battery for something over $300.00 but no date sticker. I did more investigation since DieHard is with Advance Auto in US and was advised that the B2 is what represents the manufacturer date. That is February of 2022. That is over 2 years old. So, I returned it also.

Finally, I was able to locate a local “Interstate” dealer and purchased the correct battery with fresh date sticker. H9 L6 95R Group Size, 950 CCA, 1180 CA, 110 Amp Hour Capacity, LEAD – ACID battery.

Also, I was about to use charger/ maintainer, (to keep settings) but some are “smart” chargers and they charge only if they sense battery. So, if you connect it to battery cables only the charger could cut power off. Not sure about this. So, not loose settings I connected just jumper cables to battery in my second car. Did the swap and I can confirm that I did not lose any settings.



Now regarding coding, I have also 4amp charger/ maintainer and scanner Autel MK808.

During coding on the early models (under 2012) A8 you would go address 61 BATERY REGULATION (not 19 gateway)

On my Autel MK808 I go to:

SERVICE

VIN / AUDI

PERFORME BATTERY ADAPTATION

61 – Battery Reg.

Channel 003



Three fields appear:

Rated battery capacity (110 AH)

Battery manufacturer (Akuma)

Battery serial number (this field is empty)



My new battery is 110 AH = correct no change.

Once I input / change manufacturer or serial number field.

“I get message out of range”



Questions

Should I use channel 001 instead of 003 in the above steps?

Is my scanner Autel MK808 compatible for this process (battery adaptation).

 

FWIW, whole battery maintainer/charger step is optional but not critical on D3 in battery swap context. I don't bother. D3 holds most settings if battery dies or is pulled. You reset the date/clock w/ MMI, run all the windows full down, full up to restore the one click down and especially the pinch protection related to auto up, and that's about it. Old experiences from prior generations of lost radio stations, needing to enter a security code into it from a perhaps lost paper card that came with car when new, etc., don't apply.

 

Yes, new battery will work without coding it in. But coding it will optimize performance, charging profile, capacity management, and likely longevity.

In my case I’ve replaced my battery twice in 12 years of ownership. First battery when I got the car (used) was an OEM one, so almost certainly replaced by Audi, so coded. Based on its date stamp, it gave 8yrs of service before it failed. Pretty good run.

I replaced it with an OES (rebranded Varta, so same as OEM) one, having to do the old parts store parking lot hotswap special as I was away from home and needed to get back on the road. So I didn’t code it, and as it seemed to be working ok, never got around to actually doing it.

Anyway, I only got 4yrs service out of that battery.

Whether that was because it was just a random early failure, or the early failure was caused by not coding it is hard to say. But assuming the aftermarket Varta (aka Duralast Gold) battery was of equal quality to the OEM Varta, not coding it was the only true variable, and it crapped out early. Go figure.

The last battery change I did, I fully charged it first, then properly coded it with VCDS and the BEM code. So I guess we’ll see how it lasts. At this point it’s likely to outlive the car, so I guess I’ll never find out….