Flat Battery
 

My 2002 X5 3ltr deisel is suffering from a flat battery problem, I had a new battery fitted in Oct 07 and all seemed well for some months until one day I suffered a flat battery and therefore failure to start motor. I removed the battery and returned it to the auto electric cothat supplied it., They charged it and and assured me it was OK and was showing 885 crank amps. Again all was O.K for a few months then the same thing occured, I then removed battery again and charged it myself until in the green on my hydrometer. Again a few months later the same thing happened again, I jump started the vehicle and took it to the auto electric company, they ran tests and reported that the navigation system was powered up approx 30 mins after the ignition was switched off and drawing 1 amp for that period, once that time elapsed there was no draw. Does anyone know if this is normal.

Regards John X5 NZ

1 amp draw for 30 minutes won't drain a battery... the vehicle rest current draw specs from BMW is after the vehicle sits for 16 minutes it should draw 0.038 amps or less. (38 miliamps) and the proper way to measure this is with a graphing oscilloscope and an inductive low amp current probe that clips over the ground wire and reads inductively. The vehicle needs to be monitored over a long period of time usually to see if it wakes up overnight which is a pain to find as it usually only happens sporadically. (as you said, only happens every few months)

Hi Weasel
Thanks for reply, it seem on further investigation that the nav computer stays powered or repowers whenever it fells like it, do think this is posible? Will removing the disc solve this?

That sounds plausible, and most likely, but no removing the disc wouldn't help. What I would do is just unplug the power from the nav computer then recheck... odds are the nav itself may be the problem.

have you got this problem sorted out as i am have similar problems and just got back from auto electicians haveing solved nothing. It can go a few weeks then there is not enough power to start. A few weeks ago it did it after a 100 mile run parked up and the next morning it would not start.Surly it would have to be a massive drain tas it is also a new battery.
please help if you can

I had the same problem over a year ago with my 2001 4.4i - turned out to be the mobile phone. The Motorola V50 I have is not the original BMW one and does not have the necessary BMW firmware to properly shutdown when the ignition is turned off. This also prevents the NAV and possibly other accessories from powering off resulting in the gradual draining of the battery.

If you have a mobile phone fitted - try unplugging it every time you leave the car to see if the discharging problem stops. If it turns out that this is the problem - there are some outfits that can upgrade your phone to the BMW firmware. BMW ready phones are also usually available on eBay.

Hi guys
I'm also having similar problems.. armed with this info I'm seeing my machanic Thursday and will tell him to check what you guys have mentioned...
Will let you know outcome..
Have had it already checked over a few months ago and do have a very small drain but nothing that would give the trouble I'm having..
Many thanks
Tony