Flat battery in cold weather

[kat147]

Hi, Just wondering if anyone can shed any light.

I have a 1999 mk4 Golf 1.9 gt tdi and am having problems with the battery in cold weather (anything below 0 degrees) When I try to start it in the cold the battery sounds drained, sometimes theres just enough power there to fire it up and other times its just dead and has to be jump started. Once it has been started it is completely fine until it is left for a day or two again.
I did have a problem last year with the wiring. Im not sure exactly what was done to fix it but some of the wiring had fused together and had to be by passed, the rear wiper motor had also burnt out and the fuse for it has now been removed. Another thing I noticed the other day is that sometimes the front electric windows will work without the key in the ignition. Do you think there could be a problem with the ignition causing a live drain on the battery? How would I go about getting this sorted?

Any help would be appreciated as I am starting to get to the end of my patience with this car having already spent about £1500 on it in last two years. But I really love this car so would like to get it sorted.

Many Thanks
Kat

[warrtydog]

Hi
First thing to do is get it charged up to max and then get it drop tested to see if it holds a charge under load. If the drop tester voltage is not steady and slowly,or quickly drops then your first action I suspect is a new battery. After that get an electrician to test your alternator is charging the battery.
As for your windows winding up with no ignition key in that is usually a normal thing to save you having to refit the the ignition key if you are about to lockup your car and you have left open the front windows.
Hope this is of some help to solving the problems you have.

cheers

[warrtydog]

Hi
Having just reread your post it sounds to me as though the alternator is OK because once you start it and drive it the problem goes. I definitely think the battery is losing charge over a couple of days and is in need of replacement. Make sure you get a good quality one of at least 70 amh rating as it need the best and highest rating to turn over a high compression diesel in this cold spell we are suffering presently. Also there could be live feed draining it as you say, again you would need to see an auto electrician to determine if this was the problem after doing the other things first.

Cheers again

[Eddo1968]

I had the same problem on my 2005 A3. Everytime the car was left in the cold (below 5C) the battery died over night. After 2 years of complaints and my dealer being unable to replicate the problem (they refused to leave the car outside for insurance purposes) I demanded a replacement car which spurred them into action. They eventually discovered that the temp guage on the central computer was triggering the brake lights when it fell below 5C which obviously draiined the battery. They replaced the part and problem resolved. Let me know if you are still having this problem and I can dig out the dealer documentation (in french) for a more technical explanation

[wobbla]

Sounds like your battery assuming its not new. you need a good rate of cold cranking amps in this weather.Check original cold crank rate for your car and get just slightly higher and then get a new batt with that rate.I have 3 cars and all had same symptoms like yours but not anymore.I done some research and as far as i know Kirkland battery from cosco are extremely good value for money and guarantee is impressive.Mind you need to have a membership i think so phone em first for price and stock availability etc to avoid a wasted journey.Hope this helps and good luck.

[Mike67]

I had the same, battery went flat over night in cold, had battery tested and replaced, all seemed ok. One week later same again - so I thought alternator, anyway got a decent garage to test alternator - fine on start up and under a load, 7 day old battery was a dud and unserviceable. Went back to place it was fitted and got a swap (got a better branded battery too)
Fingers crossed all should be ok now, just need the cold weather to go !!!

[pt_asiek]

I had the same problem on my 2005 A3. Everytime the car was left in the cold (below 5C) the battery died over night. After 2 years of complaints and my dealer being unable to replicate the problem (they refused to leave the car outside for insurance purposes) I demanded a replacement car which spurred them into action. They eventually discovered that the temp guage on the central computer was triggering the brake lights when it fell below 5C which obviously draiined the battery. They replaced the part and problem resolved. Let me know if you are still having this problem and I can dig out the dealer documentation (in french) for a more technical explanation

Hello, I have 2007 A6 avant. Looks like no one is able to find what is draining a battery when temperatures drops around below 5C. we bought this car about 2years ago and we have same problem since. We have spend a lot on small repairs in different garages including Audi. Problem still remains. I wonder whether you could give me some more details how your car was fixed. I would really appreciate that.

[Eddo1968]

Hi, unfortunately it's been a few years since this happened and I'm on my 3rd Audi since selling the A3! I checked to see if I'd scanned the dealer documentation after they fixed it, however unfortunately I can't find it. It's pretty much as I described originally. It was driving me mad because, as you've discovered, it's very difficult to replicate. Eventually they found out what it was after I got Audi France involved. As far as I can remember the temperature sensor in the main computer was activating the brake lights below 5C therefore draining the battery. The only thing I can suggest is that the Audi dealership leaves it out overnight and then traces it back. I bought the A3 orginially as an ex demo from an Audi dealer and after about 3 years of this seasonal problem I'd had enough and demanded that they fix it or provide me with a replacement car. I still find it weird that in this day and age they haven't logged a fault like this across the Audi network with solutions. Good luck!