I disconnected the charger at 11.30pm, and reconnected the battery. After setting the clock and one touch windows all is good. Left the car until 9am this morning and nothing powered down overnight.

I'll see what the weather is like later and perhaps hook the car up again in trickle charge mode directly on the battery post (-) and battery(+) and leaving the car connected to the battery,

I found the BCM messes with the charging of the battery and the only way to fully charge the battery is to disconnect from the car and charge on its own, I left it connected to the car and on charge for 3 days and it still hadn't fully charged, it took 18ish hours iirc to charge fully when disconnected from the car with my 6A RING charger, I was leaving it plugged in and it was still reading low on the battery meter on MMI before hand.

Not sure whats going on now.

Checked battery with a DMM last night at 9.30pm, reading 12.6V with the car connected and awake. Went to go to work this morning and back to square one, battery meter on 15% and all convenience functions disabled.

Either the battery is ***** or I have suddenly developed a worrying persistent current drain. Thing is once the car is in this state the battery stops discharging.

I sat in the car yesterday early yesterday evening and watched the BCM with VCDS as the car went to sleep. After switching off ignition car was drawing 7 amps, which over the next 15 mins dropped to 4.5amps and then lots of relays clicked and the car went to sleep. Sadly VCDS also lost connection to the BCM at exactly the same time.

Tomorrow lunchtime I'll visit the place where I purchased the battery and get them to test it and see what it reveals.

Right, I've just got back home and stuck the DMM across the battery, it was reading 12.54 volts after driving the mile back from work. Battery indicator was again at about 15% when leaving.

I've attached a VCDS scan of the car as it was tonight, but I had not cleared the codes since disconnecting the battery. Some of the listed faults were clearly present before I did that anyway.

I've also attached a measuring block log of controller 61, the engine and everything else was off but the car still awake. Column 3 shows the current draw recorded by the BCM of 8 Amps.

Something I am wondering, although the alarm siren is not reporting any faults is, can it be causing an issue since the alarm is one of the last things to be shut down by the BCM as the main battery discharges and once the battery gets to a certain point it stops discharging. I have read of drain issues caused by the siren on here, so as long as its not raining tomorrow I might get time to access the siren and disconnect the wiring.

When I got the car the siren was dead, so I got a used from A8parts. That one also failed 3 months later, so the one currently fitted has been in the car for 18 months but was also secondhand from a8parts when it was installed.

I still have the two older ones, and I know the car is not happy with it just disconnected so if the current draw drops after pulling the connector I could refit one of the other dead ones perhaps?

If you need any current draw values from my D3 for comparison let me know +++

Hope you manage to fix this problem without too much further grief.

Something to compare against would be handy.

With VCDS connect to controller 61 and look at the measuring blocks one of them (channel 2 I think) has current flow in amps. With the engine running it reports a positive value since you are putting charge back into the battery. Switch off the engine and press/hold stop on the keyless until the steering lock engages, wait until the interior lights go out and that is where I get the 8 amps from (A negative number since I am now taking power from the battery)

My car has AMI and the full phone kit and TV which appear to be powered until the car goes to sleep, but a rough idea would help.

My car goes to sleep after 15mins but I loose the BCM through VCDS because the CAN gateway goes to sleep as well.

I don't have phone or bluetooth, shouldn't matter too much. Leave that with me and I'll get my values to compare. If you don't mind waiting 36 hours as I'll do it Friday +++

8 amps with everything off even if it's not completely off but in standby seems a lot. What about that fan control module you mention in another post? I think it's getting power as you can have residual heater on with car switched off and locked. Since you are having problems with it may it's draining your battery. Try pulling the fuse for the fan and see if current draw reduces.

I pulled the alarm siren this evening, there was a drop in current draw on the BCM from 8.2 to 7.9 amps with everything off and the car awake. Question is supposing those 300ma are the siren batteries charging how long would it take for the BCM to shut everything off if that 300ma drop does not stop. Poole Audi have quoted £139inc. VAT for a brand new alarm siren, they sent me the ETKA screen shot. Question is do I spend that on something that may or may not fix it.

Although I have issues with the heater blower controller, I have the solar sunroof, so when you switch off the ignition the supply switches to be powered by the solar panels on the roof. That switch does happen because when the sun is out you can hear the heater blower running, and in the dark all is silent.

I've used the car a number of times today, first thing to drive to work and it was the usual 15% and keyless entry off. Same again at lunch time and this evening. Everytime its always started well without any hesitation.

I am doing a long drive this weekend, so will keep an eye on it.