Hi Guys, I need your help. My car (2006 525i) has been giving me a bit of trouble lately.

It started about 2 months ago when I would start the car first thing in the morning, it would tell me I had an "incresed battery discharge" and I would have to reset the date and time. Then sometimes while driving the radio would go dead for a split second then be normal then go dead again, always for a second or two, last week, while driving at night, i was sure I saw my headlights flickering, which coincided exactly with the radio spluttering issue. Tonight, I was accelerating to join the motorway and suddenly, the radio went dead, the iDrive screen went blank and the headlights went off...lasted about 1 to 2 seconds...scared the shit out of me...I really don't want to be joining a motorway in the dark when my headlights decide to go off! I'm guessing it's either an alternator or battery issue, has this happened to anyone before and how do I find out what's cauing the issue. I bought the car two years ago and I'm guessing that the battery is the original from new...how can I check?

Thanks in advance because I know someone in here will help me sort it out.....I love this place

 

Sorry about the double post.

 

Check the voltage at the jump start terminals under the bonnet. Engine off should be around 12.5V, engine running 14.4V.

As you say battery or alternator. If it's the alternator chances are it's the regulator which can be replaced without removing the alternator and is a lot cheaper than a whole alternator.

 

IF you got 5+ years with the original battery you should kiss more than that famous Irish stone!! The battery manufacture date may be stamped on one of the battery terminals or marked on the case (hard to see because the battery is recessed and has lots of "stuff" all across the top.) But even if it was replaced, batteries can fail at any time and for many reasons.

As was already suggested verify the alternator is cranking out the mandatory 12V + and then get thee a new battery.

Search the posts about that with battery manufacturer alternatives and registration suggestions.

 

+1
The voltages I measured (at the battery terminals) after I installed my new battery. Before going into sleep mode, sleep mode, and motor running.

 

Cheers for the help guys, I checked the battery today with a meter, engine off 12.4V, engine running, 14.8V. If I get a new battery, I've read posts on here about registering a new battery, whats all that about?

 

Make sure the new battery you get is the same model size and capacity as your old one. Yes you will need to get the battery registered. It can be done in DIS if you stay with the same type and size of battery and wont take more than 15 minutes to register. Either the dealer or a indi shop around you that has DIS can do the batt registration. But dont skip it! You will kill your new battery in less than a year if its not registered! Take it from someone who has been there and done that.

If after the new battery and registration the problem comes back, then your IBS sensor has failed and needs to be changed. Its attached to the negative battery terminal (1 piece) and costs about $200. You can change that yourself and wont need to get it coded or anything.