car battery drain

comanche_cor

Hi,

Am having problems with a battery drain in an 2001 e46. The story goes as follows:
- car not starting after left idle for a few days, replaced battery guessed that battery was ~10 years old and was just past its best. Voltage was dropping to ~11v alternator putting out ~14v
- new battery did not start car (did not return it as bought in Belfast when I live in Dublin), new battery read ~9v jumped the car & took for 20 minute spin, car did not start again the next morning
- brought car to my mechanic, due normal servicing anyway, we decided to leave fuse for air conditioning out to see if the Final Stage Resistor
- battery still dying so decided to disconnect battery from car completely over night and read voltage.
- voltage dropped from 12.21 to 12.17

So does anyone have any opinions / suggestions, was the new battery foo-barred or is the battery now foo-barred due to being drained so often?

Perhaps I should test the original battery to see what voltage its at after sitting for a few weeks in the shed to see if it is dropping charge after all?

Any ideas?

Thanks

shawnee

Need to take the car to an auto electrician to test this. For the moment you can buy an item that you put on the top of the battery that will disengage the battery without removing it. Will stop battery going dead ! Many have them on classic cars and campers. But You'll need to visit the auto guy if you want the problem sorted.;)

comanche_cor

shawnee wrote: »

Need to take the car to an auto electrician to test this. For the moment you can buy an item that you put on the top of the battery that will disengage the battery without removing it. Will stop battery going dead ! Many have them on classic cars and campers. But You'll need to visit the auto guy if you want the problem sorted.;)

Yeah that's what I am thinking - anyone know of a good auto electrician in either west Dublin or Dublin city center?

El Guapo!

Do you have a multi-meter?

comanche_cor

Dean09 wrote: »

Do you have a multi-meter?

yes - used the multimeter to do some simple tests. But am open to people suggestions, know next to nothing about using the multimeter.

alpahaeagle

Stupid question is it a diesel ?????

The reason I ask is it sounds like the issue I had with a R75 diesel. Drove to work car started no issues. Went to the car after work @ 9 hours battery dead. Could not jump start the car.
Bought a new Battery and she started straight away...Great I thought. drove home that night and @ an hour later battery was flat. After taking it two grages and been told that the alternator was at issue. Took off the alternator got it checked, the alternator was fine... Turned out to be the Glow Plug relay was naffed. After I found the answer on the web. Removed fues for the glow plugs and I had no more issues....

comanche_cor

alpahaeagle wrote: »

Stupid question is it a diesel ?????

No such thing as stupid questions

Fraid its a petrol ...

El Guapo!

Have you tried checking the drain on the battery while pulling fuses to see what circuit is causing trouble?

comanche_cor

Dean09 wrote: »

Have you tried checking the drain on the battery while pulling fuses to see what circuit is causing trouble?

Kinda - I wasn't sure if I was going about it the right way so gave up! .. I had the negative battery cable in series with the multi-meter to the battery. Is this correct?

El Guapo!

Disconnect the positive and connect the multimeter in series to it. Watch for the current draw and start pulling fuses and when the drain goes away, at least you've narrowed your search down to that circuit.

Edit: I'm not the best at explaining things so this vid will give you the jist of it.

dev100

Is the altenator okay? It could be as simple as its not charging battery. When you go to start car do any of the ignition lights come on or will radio start? or is it completely dead? Make sure its nothing as stupid as a boot light left on etc doubtful though

Ooh be careful checking for amps. As a sparky once told me. Its not the amount of volts that can kill ya its the ampage
Keep hands well away from probes if you go down the road of testing yourself

comanche_cor

Dean09 wrote: »

Disconnect the positive and connect the multimeter in series to it. Watch for the current draw and start pulling fuses and when the drain goes away, at least you've narrowed your search down to that circuit.

Edit: I'm not the best at explaining things so this vid will give you the jist of it.

Thanks - good video, will give this a go tonight.

comanche_cor

dev100 wrote: »

Is the altenator okay? It could be as simple as its not charging battery. When you go to start car do any of the ignition lights come on or will radio start? or is it completely dead? Make sure its nothing as stupid as a boot light left on etc doubtful though

Ooh be careful checking for amps. As a sparky once told me. Its not the amount of volts that can kill ya its the ampage
Keep hands well away from probes if you go down the road of testing yourself

Yeah its not completely dead - lights come on and I get a slow click click click. Only once have I never gotten anything from it ...

When to try to start it last night - no joy. Voltage in the battery dropped from 12.17 to ~10 volts after I tried to start. Then went up to 12.12 later and stayed at that till this morning with the battery disconnected...

LLU

had this happen on a car a few years back. Reason was a blown diode in the alternator was pulling a couple of amps when engine was switched off. Was able to get a recon alternator fairly cheaply to solve the problem.
A clamp ammeter would be the quickest way to check this out without having to disconnect any wires.