Z4 Roadster (E85) Charging Issues?

Hello

I have a 2006 and it is my daily drive. A few weeks ago, I had the battery go flat so I replaced it with a stock one. Now this one is discharged and I had to charge it up. No idiots lights re alternator/battery ever came on.

My question is if the issue is the alternator/regulator arent working, wouldnt I expect to get some idiot light indication that charging was not taking place? Or maybe I got a defective battery?

Thanks all!

Or maybe you have a slow drain. Searching on "battery drain" will turn up lots of info.

Thanks for that. I will put my ammeter on it, but I do drise it for about an hour every day so I would be surprised if that wasnt enough to keep it charged even with a slow drain.

It sounds like you have a paracitic draw somewhere in your car. If you can find where the draw is from you can fix it.

Thanks. I will test to see the draw on the battery when everything is shut off and go from there.

Put a voltmeter on it while running. Sometimes a regulator will fail and not light a battery light. Should be around 14.1V.

Uber-Fritz, just had to change out my alternator. Battery was not totally drained, but the alternator was cutting in and out at its leisure. I only had about 11 volts on the battery the last time I checked prior to the change, and then it sloooooowwwwwly started to charge. Only would hit about 13.7 volts though. My indicator was the "complete" dash started lighting up real slow. Didn't notice it until night time. Good luck.

Originally Posted by Uber-Fritz

... it is my daily drive. A few weeks ago, I had the battery go flat so I replaced it with a stock one. Now this one is discharged...

Originally Posted by dougmcintyre

Or maybe you have a slow drain...

If he drives the car every day, the battery should be fully charged, and it takes more than a slow drain to kill a fully charged battery overnight. His problem is that his battery is not getting charged.

Originally Posted by vintage42

If he drives the car every day, the battery should be fully charged, and it takes more than a slow drain to kill a fully charged battery overnight. His problem is that his battery is not getting charged.

Agreed. But I was throwing out ideas based on the description "daily drive" - which, in my experience, means anything from "I work from home and drive the car most weekends" to "with my commute the car is drive every day for at least a couple of hours."

When I have a mysterious problem, I will try any quick, easy, zero cost, remotely related test. Sometimes you get surprised.

Originally Posted by dougmcintyre

... When I have a mysterious problem, I will try any quick, easy, zero cost, remotely related test. Sometimes you get surprised.

Like just checking the battery connections. The resistance from dirty or oxidized posts and clamps are sometimes found to be the cause of poor charging.

Hello, thanks everyone! I drive it about an hour every day 1/2 highway; 1/2 city. No parasitic draw that I can detect. I have to grab a new voltmetre to test the alternator.

And the terminals are tight and squeaky clean.....

I doubt it will be the alternator. When mine died NOTHING electric worked on my car. The trans wouldn't shift out of 4th, the blinkers didn't work, the clock shut off, everything. You'll have multiple lights on if its the alternator. My service engine light, battery light, abs and traction controll lights all came on. A Fully charged battery should be 12.6 or 12.7 volts. Check what your alternator is rated at. You may just have a bad battery though. I would definitely get it checked just to be safe.

When the alternator went out on my '04, the dash board lit up like a christmas tree, with battery and other lights on.

And the final answer appears to be,....., the brand new battery isnt holding charge. What are the odds? So back it goes. I feel like maybe I should have tested it first before considering more complicated possibilities, but I just dont jump to "new and defective" as a likely possibility. Live and learn. Thanks for the advice everyone.