paneuro

Hi, I have a 2008 530D E61 Msport and I get the battery symbol coming up on the dash when I stop and leave the radio on>
Is this a sign that the battery is on the way out? If so can anybody tell me what the proper battery is for this car? thanks Paneuro.

seanjordan20

Battery light always means alternator. Have your battery and alternator checked.. These cars came with different specs meaning multiple battery specs. Open the trunk and look at your battery. Pay attention to the size and ah spec

paneuro

I had the battery checked and was told it needed replacing, also in the process of replacing engine earth strap as the old one just disintegrated in my hand. I will keep you up to date once the work is complete. Paneuro.

scottalexander

Let's figure out if your battery needed replacing because the voltage regulator brushes were worn or faulty (inside the alternator).

JayArras

...or if it was over 5 years old and due for replacement anyway..

paneuro

update, fitted new earth strap at £35GBP, also new battery, registered new battery as it was 95AH, It started first pop. I then put a meter accross the battery when it was idling and the reading was 15.67volts. How does that sound ? Paneuro

scottalexander

Generally, when the voltage spikes to that high of a level its indicative of the voltage regulator malfunctioning.

The reading is typically in the range of 14.0v - 14.5v

paneuro

Hi Scott,the story from the beginning. when I had the radio on with the car stopped it would play for 5 or 10 minutes then I would get the battery symbol on the dash. after about a month or 6 weeks I had driven about 7 miles and stopped to pick something up and it just refused to crank over, I sat for maybe10 minutes and tried it again and it started. It was fine for about the next 4 to 6 weeks and then one day after a 12 mile drive it refused again, I had to jump start it. when I got home I tried to restart it and it would not crank over. I tried charging the battery but no joy there. I started to investigate the earth strap from the engine to the chassis and it just disintegrated in my hand. I also had the battery tested and was told it required replacing.
I fitted a new earth strap and a new battery and it started first press of the button. You seem to still say its the alternator? I assume you have had alternator trouble before? Have you repaired one and what is involved? I know where it is in the engine bay and it doesn't look an easy job to remove it. If there are parts available to repair them then I will have a go but I don't know anybody who can test these things. If I run it as it is at the moment is it liable to overcharge the battery or can it do more harm. thanks Paneuro

seanjordan20

In October I let you know that if you see the battery light you have an alternator issue and to check the battery and alternator. The reason why is because driving on a bad alternator can cause the battery to go bad. Since you have replaced the battery you need to address the alternator or you are going to be spending money on another battery. Someone above recommended you replace the voltage regulator. I don't ever recommend it but in your case that is what I would replace. It's easy to do and you don't have to remove the alternator off the car. There are many videos on YouTube to watch to see if you can do it. Let us know if there is anything else you need help with to solve this issue.

scottalexander

I recently pulled out my alternator (4 aluminum bolts, one time use only bolts). Say 15 minutes of time.

I bought a new voltage regulator and installed it (180 amp).

The job was easy and now I know 2 things:

- my old lead brushes were worn ( I replaced them for circa $30). The brushes and voltage regulator are housed in one unit
- the old slip ring on the alternator was super dirty ( I cleaned it )

Instead of spending $400+ dollars on a new alternator, I did the job for cheap.

As a rule, if your alternator is putting out 15.5v the voltage regulator is unstable.

Now that I have a new voltage regular and brushes, I know my battery and electrical system are sound.

Its an insurance policy to know its one less thing to go wrong.