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OK, I've got a 04 330Ci convertible, and about every 2-3 days if i don't drive it, the battery will be completely drained.

On my old 03 330Ci coupe, i NEVER had this problem never had it on my 99 328i either... They replaced my battery under warranty, said it was normal and to drive it more often.

WTF?? I'm so pissed right now.... Someone shed some light!
 

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they check out ur alternator at all ?
 

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there is no way that is normal, maybe you got a defective battery or the alternator is not functioning properly, but like i said that is not normal and you should go back to the dealer and have them fully check the car out. hope this helps
 

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BrandonClaps said:
OK, I've got a 04 330Ci convertible, and about every 2-3 days if i don't drive it, the battery will be completely drained.

On my old 03 330Ci coupe, i NEVER had this problem never had it on my 99 328i either... They replaced my battery under warranty, said it was normal and to drive it more often.

WTF?? I'm so pissed right now.... Someone shed some light!
I got a 04 coupe (back in Oct '03) and for the first 2-3 months I had it...my battery died every 3-4 days (I travelled for work during the week) that I didnt drive it as well....I brought it the dealer and they recharged it...and no problems since. Btw, I had no time to bring into BMW for the 3 months and when I got home on Fri, called roadside assistance to jumpstart ! It was great.....!!!
 

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BrandonClaps said:
i'm not sure if they checked it, if i bring it in again, it'll be the 4th time.
Chk the 3 maintenace invoices and see if they recharged it. If not, recharge it and if the battery continues to die then I would ask for a replacement. Odd how the dealer would be relucant to replace something as trivial as a battery after 3-4 visits....!?!??!!!
 

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BrandonClaps said:
i'm not sure if they checked it, if i bring it in again, it'll be the 4th time.
If you drive it every few days and it keeps working, then its not the alternator.
Have you done any electrical mods to the car such as install radar detector, non OEM handsfree kit, stereo, etc? Sometimes those devices drain battery if not switched off.
Make sure all lights such as trunk light, interior light turns off when you leave the car(May or maynot be a problem) I think BMW has a safety feature that shuts them off after 15 minutes that you have not used the car.
 

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Discussion Starter #8
no aftermarket dvices at all.... I brought it to the dealer today, they hooked it up to a battery tested, said the battery and alternator were fine. When i brought the car home, i hooked up that BMW battery maintainer to it.
 

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sounds like your dealership is not doing proper diagnosis to your car...you might have a parasitic drain...could be your car not going to sleep after 16 minutes (power saving feature built in bmw's)...or you not turing off lights, etc...if the battery is fine and the alternator checks out good....something is pulling a load on the battery....ask them do a parasitic drain test..and if there's something pulling power..that test should show it...after that, they'll probaly try to find what module or what is pulling that load...hope this helps..
 

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99.9% chance your alternator isn't charging your battery.

Get out your multimeter and measure the following:

Car off and the battery should read 12.6V for 100% charged. 12.4-12.5V is typical and this will be around 99% charged.

With the car started and alternator charging the battery the battery voltage should be between 13.5V to 14V. If it's not then the alternator isn't charging the battery.

Another way to test is to start the car and then pull the negative battery terminal and see if the car continues to run. This is crude and dangerous way to do it because the alternator voltage has ripple on it with voltage spikes/transients. These spiky voltages can damage sensitive electronics because the battery isn't there to smooth out the voltage. Also, the alternator may be producing enough voltage for the car to run but not charge the battery. But, typically when an alternator goes it completely dies.
 

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do not pull the negative battery...you will fry your control modules..and likely causing more damage..you can try the multimeter over the positive and negative terminal....if you brought it to your dealership im pretty sure they tested it with the midtronics..awesome test equipment...your car should be still under warranty...try to go to another dealership...its clear to me that the technicians at the place you bought it from are just throwing parts at it and hoping to fix itself...and not really diagnosing it and fixing the problem
 
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