[LordHefner]

Originally Posted by snapdragon

I have had three batteries with three different coding part numbers:

When the OE black Varta battery that I bought the car with (coded 4E0915105A) started to become weak, I bought a new Varta silver i1 110Ah for £119 and coded as (4E0915105DL). The next 18 months were hell with the battery going flat randomly and sometimes seeming to charge really slow when driving and having very little in reserve when sat parked with stuff on. Had to get Green Flag out 4 times. I put it doen to the bugs in the BEM and other control units and the car's age.

October 2013, I went to another of work's campus, parked up and sat with my laptop on for 10 mins and when I came to start the car it was dead.
I did a 'click and collect' purchase on my phone from Eurocarparts for a Lion AGM 700 for £134 and got a taxi there and back. Put it on and coded (4E0915105AK as this is newer model's 95Ah AGM part no.) never had a problem since and can sit with heated seats radio and blowers for ages, totally predicatble. Always 100% unless I do the above for ages and things shut of nice and sequencially and not all at once when it's too late as before - now, even when everything has shutdown, the car still starts as normal, but before it would just wheeze half a turn and stop.

What is more, I have a cigar-lighter voltmeter and this was always 12.3v and occasionally went to 13v. Now it is always >13v and up to 14.2v.
I'm sure the Varta silver was a duffer, but that wouldn't account for the higher charge voltage these days - I wonder if the 4E0915105DL coding caused a problem like undercharging.

If you can get a good deal such as with a voucher code, I would recommend an AGM battery, they really seem like the next step up and can withstand a lot deeper discharging that seems a feature of our cars with their dodgy BEM software and mystery door handle activity.

I wonder if these battery codes can always be decoded by the BEM? Does it just look up charging rate and capacity in a table or is it encoded in the letters? If the former do new battery part numbers it is not aware of send it screwy? Who knows?

Did I read that right? You have to hook up the car to a laptop to tell it what model and make battery? Wow if so then it's no wonder these cars when self maintained end up having a few niggles and issues.

I noticed on a copy of my VCDS print out that so many of the parts have serial numbers with them, and my headlamps that have been changed over by the previous owner doesn't have them showing. Does Audi seriously when they fit all new parts add not only all the part numbers, but the serial numbers for them also?

Regards, Mark.