Alfa 159 Battery Problems
I have read your query about the dodgy battery on your Alfa 159 and I had the same trouble earlier this year with my 2008 Alfa 159 1.9JTDM to Preston to when my battery kept failing for no reason then I would trickle charge it overnight and it would be okay for a while but fail a few weeks later! I eventually had to be recovered by the AA (which was still provide under the 3 year deal on new Alfas) and the guy who arrived was very helpful got the car started straight away but then got me to switch the car off and lock it so he could take a reading on the battery output and it was still drawing over half an amp, which explains why the battery kept going flat every few weeks.
I took the car to Preston Motorpark the local Alfa service centre to get it looked at under the 3rd year dealers warranty only to be told the battery was not covered by the warranty so I explained that the battery was ok it was an electrical fault that was flattening the battery when the car was idle. They took the car in for a day to investigate but couldn't find anything so changed the battery and tried to charge me £250 for it, which when I said No Way and I will change it myself thanks they knocked the £80 investigation charge off asking for £170!
I decided at this point that I did not trust them in the slightest and they probably hadn't actually fixed the electrical fault so I called Alfa Romeo UK and eventually got to speak to someone in their Technical Services Department (sounded like he was from Sheffield) and they knew what it was straight away and it was covered by the warranty so he asked me to get them to call him from the service centre to discuss the problem. Guess what got a call an hour later form Preston Motorpark saying it was fixed and ready for collection at no charge to me and had been valleted too!
My advice is to contact Alfa Romeo directly if you don't get any joy with your dealer as this problem is known to them and covered by warranty. I can now recommend a very good professional dealership in Corkills at Cheshire Oaks near Ellesmere Port who have just started the Alfa franchise this year and provide excellent service at reasonable prices in my opinion.