Car appears to have a flat battery and beeps for about 50 times when trying to unlock

Spanky Deluxe · #1 08-13-2011, 08:22 AM

We got woken up this morning to a loud beeping coming from outside, about 50 beeps then off for about a minute then another long line of beeps. Looked out the window and couldn't see the source and eventually it stopped so we ignored it. We just tried to unlock the X3 with the remote and it didn't unlock, instead the beeping started again. I unlocked the door with the key manually and tried turning the ignition to no avail.

A few months ago we had some battery problems so I replaced the battery. I've got a feeling the battery might be dead and there's not enough juice for it to detect the chip in the key to disable the immobiliser. Any ideas? Will have to try to jump start it on Monday to take it to a local indie dealer. I'm guessing it'll need a new alternator so will likely not be cheap to fix.

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JCL · #2 08-13-2011, 01:52 PM

Sounds like whatever ran all night with the beeping flattened the battery. The flat battery sounds like a symptom in this case, not the cause.

First step is to check the battery and charging system. Don't assume you need an alternator unless it isn't charging.

Second step is to perform a current draw test and see what is staying energized.

Spanky Deluxe · #3 08-22-2011, 11:56 AM

Luckily the alternator turned out to be fine. There was a 'loose wire' or something next to the alternator that was causing the battery to drain. Cheap as chips fix and it seems to be fine now. :-)

tonytsai0429 · #4 09-26-2011, 05:22 AM

Quote:

Originally Posted by JCL

Sounds like whatever ran all night with the beeping flattened the battery. The flat battery sounds like a symptom in this case, not the cause.

First step is to check the battery and charging system. Don't assume you need an alternator unless it isn't charging.

Second step is to perform a current draw test and see what is staying energized.

Hi JCL,

i think you are onto something here, I'm currently going through some battery problems of my own and starting to search the forum about any related thread about battery is been flat.

my shop told me this "dead" battery has happen to lot of people with X5, some think its the battery, and end up replacing multiple times of battery.

some think its the alternator, replaced the alternator and then ends with square one, dead battery.

My shop has gotten this type of case in SoCal, where a faulty resistor in the car might be off, something like a air-con fan control, it just keep blowing, till the battery is not able to support it.

and the AAA told me a 7 years old battery could also be the case?

now, should i change both, or just battery first, and faulty resistor second, or just do both and get rid of anxiety at one shot?

x3oiler · #5 09-27-2011, 07:11 AM

While you are waiting consider an automatic battery isolator. Will isolate the battery once it drops below 11.9Volt. You can reset it to start the car. Of course getting to the isolator to press the reset button may be an issue in it's own right. I can get to it an X3 - maybe same as X5.

Low Voltage Battery Isolator - Jaycar Electronics

I have a diesel and it cranks fine via the isolator - well nothing has blown up yet.

Update: nope some issues. Thought better to update rather than leave bad advice standing. The motor cranks as stated but I suspect the isolator drops the voltage to the car electronics enough during cranking to really screw them up. e.g. loss of stability control, loss of electric power steering assist. All fixed on restart though. Removed the isolator and all good again. Next experiment will be to put the isolator not in the cranking circuit from the battery but in the secondary circuit - the circuit that is probably causing the drain anyway.

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