Battery drying out

[Billman]

Hi,

i have a problem with the car. If i let the car for 2-3 weeks without moving it the battery is empty.

I drive then for 1 hour. after 10 days is empty again.

To day i measures the amperes of current draw and it was 0.1 A.

Any ideas? What could be wrong. When the engine starts i see 14 Volts in the dash and in the Laptop through the ECU.


regards

[UrS4boy]

My guess is you have a dodgy voltage regulator that is working sometimes and not others. When it is NOT working, the voltage is spiking up and boiling the water (and acid) out of the battery (BTDT on a 1980 Jetta back in the day). Either that or your battery case is fooked.

[Billman]

My guess is you have a dodgy voltage regulator that is working sometimes and not others. When it is NOT working, the voltage is spiking up and boiling the water (and acid) out of the battery (BTDT on a 1980 Jetta back in the day). Either that or your battery case is fooked.

Where is this regulator? When the engine runs i have always over 14 Volts. During a log with VEMS yesterday it recorded min 13.76 and max 14.24 Volts.

The battery is a Bosch Silver. Car is an RS2 with the engine in the trunk.

[EspenW]

The battery is a Bosch Silver. Car is an RS2 with the engine in the trunk.

Could the battery be overheating due to the engine being back there?

[Billman]

uppppsssssss.....sorry

battery in the trunk. front engine

[prj]

[A80Avant]

are you sure its not the A-class with the 2 engines??

[UrS4boy]

Example Audi Voltage Regulator Replacement DIY

Where is this regulator? When the engine runs i have always over 14 Volts. During a log with VEMS yesterday it recorded min 13.76 and max 14.24 Volts.
The battery is a Bosch Silver. Car is an RS2 with the engine in the trunk.

Seems a bit high. In my experience, 13.7V is the maximum that the regulator should allow out. The voltage regulator is on the back of the alternator. Here is a DIY written by James M (Jamu/EmeraldUrS4) on my home forum:

http://12v.org/urs/AudiUrS4VoltageRe...eplacement.pdf

[johne]

Hi,

i have a problem with the car. If i let the car for 2-3 weeks without moving it the battery is empty.

I drive then for 1 hour. after 10 days is empty again.

To day i measures the amperes of current draw and it was 0.1 A.

Any ideas? What could be wrong. When the engine starts i see 14 Volts in the dash and in the Laptop through the ECU.


regards

If all you've said is correct then you don't have a battery problem and you don't have a regulator problem, that's just how long a battery will last if you take 0.1amp out of it.

If you really are drawing 0.1 amp when you leave the car then a 50 Ah battery will be empty in 21 days and actually will be past the point of being able to start the car somewhere more like 15 days. That's assuming your battery is new. As it ages it will last less and less.

Equally a 1 hour drive is not sufficiently long enough to refill an empty battery, hence it then only lasting 10 days.

You need to check what your discharge current is with the car at rest and start removing fuses to see where the current is going. Rather than 0.1 amp you should be seeing closer to 0.01 amp (10mA). Last time I measured mine iirc it was 6mA but it will depend on things like your stereo and any alarm(s) fitted.

The regulator is part of the alternator but can be changed without removing the alternator from the engine - not that I think it's your problem in this case.

John

[Billman]

I see, thanks. My batt is 75 Ah but i had to jump start the car for like 10 times. Battery is 11 months old but i see your point. I have a stereo and an alarm. Today i am gonna check if the alarm Battery is dead and it draws the current out. Maybe i have to use a big shwich for when I have to leave the car for several days...

In order to check the fuses i simply take the fuse out and plud there the multimeter or do I have to do it in series : Connector-fuse-multi-connector?

[johne]

My point about pulling the fuses is that you can pull the ones that are supplying power even when the igniton is off like fuse for the clock, the interior lights, central locking etc. and find out which circuit(s) are consuming power one by one. Once you've got all the fuses out you'll still have a few mA flowing and that's the current the alternator is using - which isn't covered by any fuse.

Through all of this leave your multimeter in series with the battery -ve lead which you've lifted off the battery terminal. Just be careful to not try and start the car or use any high current things like the lights whilst you're doing this or it may be "goodbye" to your multimeter

John

[benntenn67]

Hi,

i have a problem with the car. If i let the car for 2-3 weeks without moving it the battery is empty.

I drive then for 1 hour. after 10 days is empty again.

To day i measures the amperes of current draw and it was 0.1 A.

Any ideas? What could be wrong. When the engine starts i see 14 Volts in the dash and in the Laptop through the ECU.


regards

When you say "empty" do you mean no fluid in the battery or, do you mean no charge in the battery ??

[Billman]

No charge. I cant check on the fluid side of things as it is a closed style one.

[newsh]

Everything Johne says is correct. Have you changed anything on the car which might have started this problem? Stereo or anything changed or added? Have you had the centre console out?

[Billman]

so, today I got a new Battery on warranty and also installed a rally style main switch for when I leave the car for several days. I don't mind radio stations.

The alarm system draws 0.01A. I also found an old keyless entry controller that I disconnected but it didn't make a difference.

While searching on the net I found that 0.1A current draw is the average (anyone fancy measuring out theirs?).