Battery drain fault
03-06-2015, 02:03 AM
#1
AudiWorld Newcomer
Thread Starter
Join Date: Mar 2013
Posts: 7
Likes: 0
Received 0 Likes
on
0 Posts
Battery drain fault
Hi folks
A problem I’ve had with my C6 since I bought it two years ago is an intermittent battery drain which I’ve tried all sorts to trace. It’s getting steadily worse and none of the ‘standard’ techniques have traced it yet.
The dealership I bought it from replaced the battery after reading battery issues on the log but that was a ‘get it out the door’ fix. Subsequent log reads mention battery but nothing else. Often the car will sit for a week staying at 100% then hours later it’s at 10% before the auto shutdown arrests the drain by selectively shutting stuff down (I think) allowing it to always start.
Today was different though. It was 100% this morning then 50% by lunchtime, went to start it and …. nothing. All the indications looked normal but the starter didn’t turn. Tried a couple of more times before leaving the ignition on for a think. In front of my eyes the 50% charge reduced to 10% in 60 seconds – some drain for a battery of that size I’d hazard a guess! After a couple more tries it started and the battery charged slowly as normal. I had to be somewhere so didn’t get chance to apply gloved hands to cables to check for excess heating but that’s gotta be starter circuit or something big surely – any thoughts?
Car is stock, nothing changed at all. Battery was changed by PO for same snag I think but not checked recently so needs looked at I guess as a possible culprit. For the amount of grief it's had I can't believe it's still going!!
Check of current draw across the fuses is a tough one - the fault is so intermittent I could be there forever but it's next on list.
The Avant water ingress recall was done but I stripped it all out myself & dry as a bone with no water marks.
Latest update folks - Audi had the car for three days and tried to charge me £500 (another story) to find nothing. I'm now suspecting the meter that measures the battery voltage but no idea where such a device is on the car - any clues?
2007 Avant S-Line Quattro
A problem I’ve had with my C6 since I bought it two years ago is an intermittent battery drain which I’ve tried all sorts to trace. It’s getting steadily worse and none of the ‘standard’ techniques have traced it yet.
The dealership I bought it from replaced the battery after reading battery issues on the log but that was a ‘get it out the door’ fix. Subsequent log reads mention battery but nothing else. Often the car will sit for a week staying at 100% then hours later it’s at 10% before the auto shutdown arrests the drain by selectively shutting stuff down (I think) allowing it to always start.
Today was different though. It was 100% this morning then 50% by lunchtime, went to start it and …. nothing. All the indications looked normal but the starter didn’t turn. Tried a couple of more times before leaving the ignition on for a think. In front of my eyes the 50% charge reduced to 10% in 60 seconds – some drain for a battery of that size I’d hazard a guess! After a couple more tries it started and the battery charged slowly as normal. I had to be somewhere so didn’t get chance to apply gloved hands to cables to check for excess heating but that’s gotta be starter circuit or something big surely – any thoughts?
Car is stock, nothing changed at all. Battery was changed by PO for same snag I think but not checked recently so needs looked at I guess as a possible culprit. For the amount of grief it's had I can't believe it's still going!!
Check of current draw across the fuses is a tough one - the fault is so intermittent I could be there forever but it's next on list.
The Avant water ingress recall was done but I stripped it all out myself & dry as a bone with no water marks.
Latest update folks - Audi had the car for three days and tried to charge me £500 (another story) to find nothing. I'm now suspecting the meter that measures the battery voltage but no idea where such a device is on the car - any clues?
2007 Avant S-Line Quattro
03-06-2015, 08:12 PM
#2
AudiWorld Senior Member
Join Date: Aug 2006
Location: Melbourne, Victoria, Australia
Posts: 885
Likes: 0
Received 0 Likes
on
0 Posts
Your best bet is to manually check the battery drain with an amp gauge (ammeter).
you probably know the drill, but you disconnect one of the battery cables (negative is best) and reconnect with the ammeter in between.
Do not turn ignition on or attempt to start the car with the ammeter connected, otherwise the meter will probably be damaged or destroyed.
fully shut down, a normal car should pull around 30 milliamps or so.
If you find your car pulling (significantly) higher than that, progressively remove fuses from the fuse panel until you see a reduction on the ammeter.
Then trace the circuit responsible for obvious or perhaps not so obvious faults...
you probably know the drill, but you disconnect one of the battery cables (negative is best) and reconnect with the ammeter in between.
Do not turn ignition on or attempt to start the car with the ammeter connected, otherwise the meter will probably be damaged or destroyed.
fully shut down, a normal car should pull around 30 milliamps or so.
If you find your car pulling (significantly) higher than that, progressively remove fuses from the fuse panel until you see a reduction on the ammeter.
Then trace the circuit responsible for obvious or perhaps not so obvious faults...
Thread
Thread Starter
Forum
Replies
Last Post
The.aviator2
A8 / S8 (D3 Platform) Discussion
37
12-12-2017 09:24 AM