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Discussion Starter · #1 ·
Just wondering if anyone has any ideas:

I have a 1999 GLS 5 speed and am the original owner. In the cold weather my battery dies (completely drains). I have to keep charging it all the time to keep the car running. This problem started 2 years ago and is especially bad in really cold weather. Like below -10 Celsius.

Alternator is fine. The battery is under 2 years old and charges fine. Any ideas before I take it in a spend a fortune trying to solve the problem. Thanks!

Wow haven't posted here since it was the 'old' forum.
 

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TDI Lover
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Whats the cca rating on the battery could be to low for the car.
If the cca is to low it shows up when it gets cold and the battery makes less power.
 

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You can do a simple test. Put an amp meter in series with the battery. Record the current draw with everything turned off. Then unplug the radio to see if there is any change. That can point you in the right direction.
 

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Your electrical regulator could be bad, hence your alternator charges the batery but at a lower voltage. E.G. the bat recieves only 11.7 to 12.5 volts when idle and gets 13 plus volts only when rolling at speed...then your bat is charged but only at 40 to 50 % capacity, throw a very low temp condition and it wont start.
Conect an ampmenter and check for power drainage or a voltmeter and check for proper charging.
 

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Discussion Starter · #5 ·
hannaco said:
You can do a simple test. Put an amp meter in series with the battery. Record the current draw with everything turned off. Then unplug the radio to see if there is any change. That can point you in the right direction.
We did this last night. Alternator is fine. Battery is fine and has more than enough cca for the engine size. With everything off there is negligible current draw. The only thing we didn't do is unplug the radio. The alternator is charging the battery at the corrent amperage. I'm completely at a loss. It's -7 celsius here today and snowy & it started fine.:confused:
 

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Have you tried doing a load test on the battery?
 

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180 Degrees out of faze
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Humm, with everything turned off, there is negligible current draw. That mostly rules out the battery being drained due to something in the car. That leaves just the battery itself.
A load test should show if there were any internal problems with the battery. It need not be shorted to have problems. With so many drain and recharge cycles, it is possible that some of the plates have become sulfated. That could set up an internal current drain.
What is the top of the battery like? Nice and clean? Do you have a battery blanket on the battery?
 

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Just a few more thoughts. Many years ago, I had a battery that never quite went dead, but was always weak. One morning after work, just before getting into the car the cooling fan started up for a few seconds. Well, with nothing better to do, I just waited for a while, and it did it again. That constant cycling of the cooling fan just drained the battery. Tracked it down to a bad sensor.
You might get all bundled up and just sit out with the car for a while. You might have a similar problem.
 

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Discussion Starter · #9 ·
hannaco said:
Humm, with everything turned off, there is negligible current draw. That mostly rules out the battery being drained due to something in the car. That leaves just the battery itself.
A load test should show if there were any internal problems with the battery. It need not be shorted to have problems. With so many drain and recharge cycles, it is possible that some of the plates have become sulfated. That could set up an internal current drain.
What is the top of the battery like? Nice and clean? Do you have a battery blanket on the battery?
Yep we did a load test and it seemed fine. But the battery had bad corrosion on the terminals and sits in a velcro covered box with a hard shell box over it. (How it came from VW). Maybe it's time to change the battery but I still have no idea why the battery dies in the first place to cause it to become (possibly) sulfated. What is a battery blanket? Keeps the cold off the battery or someting? I've never heard of that before.
 

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Discussion Starter · #10 ·
hannaco said:
Just a few more thoughts. Many years ago, I had a battery that never quite went dead, but was always weak. One morning after work, just before getting into the car the cooling fan started up for a few seconds. Well, with nothing better to do, I just waited for a while, and it did it again. That constant cycling of the cooling fan just drained the battery. Tracked it down to a bad sensor.
You might get all bundled up and just sit out with the car for a while. You might have a similar problem.
I've only heard the cooling fan come on after I turn the car off and usually in warmer weather. It's -10 celsius here today so I don't think the fan will come on. I was outside clearing snow off the car for about 10 minutes and I didn't hear a thing and it started OK. This is a really strange problem. We do also have a turbo diesel Jetta that wouldn't start at all this morning but that's another story - has over 283,000 kms on it.

Hopefully when I move in Feb I won't have this problem as much anymore. I will finally have a garage, albeit not heated, for the car. :)
 

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The battery blanket is the insulated cover inside of the battery box. Some people remove it. The corrosion might be the root cause of the problem.
 

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Discussion Starter · #12 ·
Well had to buy a new battery today. Car wouldn't even turn over this morning. :mad: So now I'm out about $100. Hopefully this solves the problem. New battery has 650 cca. My original battery was fine and worked great in freezing weather for over 4 years. When I replaced it two years ago the problems started in the cold weather. I'm hoping it's just the current battery and that by changing it I'll be OK. Oh and I still have the battery blanket attached.
 

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hopefully you cleaned the corrosion off the terminals before you hooked up the new battery? And make sure everything is "German torque" (guhdentihte):D
 

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You mentioned that the problem is especially bad when it is really cold. Does this mean that the problem sometimes occurs when it is not below freezing?

One thing to check when you park the car in really cold weather is to see if the brake lights on the rear of the car are off. I have diagnosed cars with run down battery problems and the cause is a brake switch that does not go off in real cold weather. The brake lights come on when the car is shut off and no one is pressing on the brake. The result is a run down battery. One had to literally "pull" up on the brake pedal to get the rear lamps to shut off.

Note that the CCA rating of a battery is not the same as the condition of the battery. A battery can be rated OK (as labeled on the battery), but be defective and not deliver. Alternators should be judged on both the output current and the voltage delivered to the battery. If the output voltage is not 14.3 or higher while the engine is running above idle speed, something is wrong (excessive load on the battery or the alternator is defective).
 
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