LexusLSguy

Did you get a OEM Varta? I was going to go aftermarket but the OEM size is hard to find. For the money the OEM can't really be beat in my opinon. More so the reserve capacity not cranking amps. There are 3 or 4 batteries sizes and mine was the 2nd largest. I believe the biggest was about $330. In other words, be mindful of smaller aftermarket batteries with a lot less reserve capacity.

Direwulff

I picked up an autocraft H9 AGM platinum battery from advanced auto parts with 950cca and 105ah. Seems like a great battery for $155 with tax after and coupon code applied. Problem is I don't have a vcds and this battery doesn't have a BEM code on it for VCDS coding. Does anyone have a solution for coding it correctly with vcds if I decide to order one from ross-tech?

Direwulff

Did a little research tonight and it looks like even without a BEM code on the battery the most important thing to know when coding iis the manufacturer, the amp hours (105ah for my battery) and the date the battery was made. Autocraft and carquest batteries are coded JCB for Johnson Controls. The manufacture date is part of the serial number on the BEM code, but since I don’t have a BEM code the battery does have a manufacture date on it I can use. Or I could just use the current date since the battery is brand new I suppose. The first six digits of the serial number entered in vcds is the date of manufacture, in today’s date format it would be 081117, the remaining five digits of the serial number are meaningless to the battery management system so just put in anything there. This is all under UDS in the vcds system for the A8. Got my rosstech on order from europaparts. Once it arrives I’ll update on the MMI issue to confirm it was the battery.

LexusLSguy

The presets for the power management system are rather simple. If the settings for amperage are the same just replace one digit in the serial number to reset and make sure the code is accepted. This is the most important setting, the amperage. What I also found in the aftermarket Bosch AGM I was going to use is that amperage rating for the length of time it can supply power was much lower. I'll have to look up what that number is. ​

Stock is 92 ah for 520 min. The Bosch I was to get was only 25 ah for 120 min

https://www.audiworld.com/forums/a8-...my-a8-2919229/

LexusLSguy

Any update?

BTAudi

That's the one I got too this week, same place at the same price after coupon and tax. Great battery and made in Germany. I have a 13' and was starting to get the message to start the car so the battery could charge after 5 days or so of no use

BTAudi

The BEM code on my autocraft 9 AGM was covered by the "danger/poison" sticker.

BTAudi

The manufactured date is supposed stamped on the top corner. Per this info from interstate the Johson control battery born on dates correspond to a number for year and letter for month only thing I found was 1416 on the negative post

Direwulff

Thanks for the reply, I will peel off the danger poison sticker to get at that BEM code. My battery came with a sticker on it that said 6/1/16 so I assume that means it was made last June? My vcds came in the mail today so maybe I’ll drop it in tonight.

Direwulff

I just installed the new battery and coded it in with vcds. MMI screen still having problems, got the following fault codes on the head unit scan

1 Fault Found:
02259 - Information Display and Control Head (Front) (J685)
004 - No Signal/Communication
Freeze Frame:
Fault Status: 01100100
Fault Priority: 5
Fault Frequency: 221
Reset counter: 36
Mileage: 109973 km
Time Indication: 0
Date: 2017.08.31
Time: 08:25:33
Freeze Frame: Voltage: 13.80 V

So the issue I am having is definitely cold weather related, the colder it is, the longer it takes for the MMI display to turn on after driving around for 20-30 mins. I live in Chicago, my car is a 2011 A8 4.2 with 65,000 miles on it. Anyone have any ideas as to what the culprit might be?