I tested these fuses by pulling them and then shutting the door, waiting 30 seconds or so, and then recording the reading on the ammeter. Fuse 15 (instrument cluster) is pulling 7mA, fuse 43 (Radio) is pulling 8mA. Fuse 38 (Central Locking System) actually caused the draw to INCREASE when pulled by 13mA. Interior lights did not make a difference.

I noticed my cell phone charger was plugged in in the back outlet, pulling 15mA. For fun, I plugged in my cell phone, and the draw jumped to 600mA, so my total residual draw (48 mA) is less than 1/10th of the amount required to charge my cell phone; I don't see this amount of drain as a possible cause for my daily battery problems.

After 10 minutes or so of checking fuses like this, I started pulling fuses with the door left open to save time, just watching for changes. None of the other fuses made any difference in the reading of more than 1mA (possibly normal fluctuation or meter error). If this is not a valid check for the other fuses, how can I simulate the door being shut? I don't see a switch in the door jamb like most cars have. :/

I am leaving the phone charger unplugged and the radio fuse out and we will see how it does over the next few days. This drops my draw nearly in half, but I am still skeptical that this amount of draw is abnormal.

No noticeable chaffing on the positive cabling, and my ammeter indicates that there is no significant short circuits in the system.

 

This problem is a challage --
I thought of two things you might look at.

1. I once had a Buick Riv with auto level - I though it turned itself off when the ignition was off but one day while I was working in the garage I heard the level pump come on. I am wondering if there is something in your Audi that would turn itself on an off while your sleeping.

2. Battery test - was it just a voltage test or did they run a test under load? I'd confirm that the battery is OK by going someplace else and making sure they do the load test. Autozone has some great test equipment - the techs arn't always good but the equipment is great.

 

They hooked op a black box about the size of a briefcase, hit a few buttons, waited about 20 seconds and then said the battery is fine. I will have it tested again.

Latest update:
So with the stereo and phone charger unlpugged, the problem is noticeably worse. I think the battery is just coincidentally low; it will produce slow cranking after sitting only a few hours. Last time this happened, I did a deep cycle, 2 amp overnight charge. The problem went away entirely for a week or so, and then returned to losing power over night.

I may need to buy a data logging multimeter so i can record whats happening overnight. Will get a second battery test first though.

Thanks for the reply!

 

Ok do this-- Autozone has a charging system tester that first tests the battery then test the battery under load and finally tests the alternator when you start the car. Before you spend any more have someone do that test - not just the black suitcase thing

 

Thanks NH_USA! Autozone did a load test and confirmed that the battery was bad. I put a new one in on 6 days ago and the problem seems to be resolved.

A big thank you to everyone else for replying as well!

 

My 2001 Audi A6 2.7 has battery drain problem too and I could not start the car at airport twice after leaving it there for 10 days after I got a new alternator and a new battery last November: one time the weather was below 20 after my family returned from Florida last December and it was awful. I brought the car to dealer and they looked into it and said everything is normal and recommended I have a backup jumper. I could not believe it!!

After seeing this post, I bought a multimeter and decided to do some troubleshooting as well this weekend. I put mulitmeter between negative wire and batter minus end. multimeter reads 181 mA with all the fuses present and 144 mA with all the fuses out. As soon as I disconnected the wire which goes into the car, multimeter reads 1mA. According to the post, anything over 50 mA flags a problem. Anyone has idea about what kind of problem I am having?

Also, I expect that my radio would go to safe mode after having disconnected the battery but it didn't after putting battery back on.

I really want to get this problem fixed. any help is sincerely appreciated!!

Mike

 

Do you have factory navigation? Un-plug it if you do and see what the reading is.

 

thanks for your reply. no navigation system on this car.

 

Well, then start pulling fuses one by one and measuring the amps.

 

I did. What really puzzled me is that multimeter still reads 144mA with all the fuses out. I believe that is where the drain is.