E36 Jump Starting Issues

[Doomsdaya]

My car was left in the garage for a week, the day I decided to use it the battery was flat but the lights and aircon was still operational, so i left it for the next day.

When the next day came, I checked the car, this time the lights and aircon didnt even work, thats how flat the battery was.

Now I understand when jump starting a bmw the lights and aircon and all power consuming things should be on so as soon as i connected the jumper cables, the lights and aircon started working which was fine

After that I tried starting the car, then the doors locked and the alarm went off :thinking: i tried pressing the unlock button on the key and nothing happened until i open the door then the alarm went off :dunno:

After that all that i tried starting the car with the lights and etc on and off, but nothing happened :hammerhead: all i got was a click

 

[ETTIENNE]

...charge the battery....

 

[StK]

First find out what is draining the battery-search online for parasitic battery drain.I would suspect the FSU though.2nd is you may need to reset the alarm depending on which one you have although it sounds like the battery is still flat....

 

[Doomsdaya]

At the moment the battery is on charged, but i have been having trouble lately with it draining out quickly and its a new battery

As for whats draining it, I have an amp connected directly to the battery in the boot, i suspect this is the problem.

A friend of mine says that bmw's come with a sleep function, so even if the car is off and locked, the CPU will go to sleep after 15min but if theres current being pulled then this wont switch off. Hmmm how true is that ???

 

[StK]

Do you not have the remote wire connected on your amp?This should run from the ign live going to your HU...this will prevent your amp from constantly drawing from the battery-If you don't then maybe fitting an inline switch so you can manually switch the power off to the amp.If you don't then you will destroy the new battery(unless its a deep cycle battery) because standard batteries are not designed to be drained and charged.....What car do you have by the way?

 

[Doomsdaya]

@STK I have an E36 328i, I dont have any remote wire or inline switch. The power wire for my amp is connected directly to the battery:mmm: even my HU works without the ignition:dunno:

 

[StK]

Ok well first thing I would advise is to get a switch in that power cable going to the amp-you're not doing yourself any favours by having it live all the time.

 

[Raybimmer]

Needed a battery charger ...and a fire extinguisher .:wave:
If HU or amp are directly wired then there is always a drain on battery . Put an ampmeter in line and check current flow-should be milliamps , if 1/2 amp or more I would expect battery discharged within a few days . No problems with my 325i with pioneer HU wired direct - no amp used .Also check boot light .

 

[Doomsdaya]

OK, Battery is charged and car is firing on all 6 cylinders :excited:

Yeah i'll have to put a switch on that power cable :mmm: that is the main reason why my battery is dying off so quickly

At the moment the battery is disconnected when the car is not in use:hammerhead:

 

[StK]

Do you have an inline fuse for the cable to the amp?If so you can get a breaker for the correct amps and then you can switch it on and off at will :thumb:

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to put in place of the inline fuse

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this is what I am on about http://cgi.ebay.co.uk/Car-Stereo-Am...759306?pt=Car_Audio_Video&hash=item4cf4fd5bca