Ah, west coast...

Yeah, it is a quick process. They connect the tester to the battery jump contacts under the hood while the engine is running. That is pretty much it. They can switch back and forth between your battery and alternator to see what is going on.

Nice. Free information, such a deal!

Just a word of advice if you need either a battery or alternator, I would feel absolutely fine buying a Duralast battery from them, but I would not buy a remanufactured alternator from them if that ends up being your issue.

Thanks for that. I have an Interstate that has a month left on the replacement warranty. If it is the battery, I'll be going back to them to try to get it replaced. If it is the alternator, I was thinking that this would work:

Your Parts Search Returned 1 Part(s)

Do you have any other recommendations for alternators? Unfortunately, it seems as if the place that did the $200 rebuilding mentioned in a DIY here is no more...

The link you provided looked pretty good. It's Bosch.

You can also look here;

www.bavauto.com

Pelican Parts - Porsche Parts & BMW Parts - Automotive Parts and Accessories - Porsche & BMW

If you are in a pinch and can't wait for shipping, you may be able to find a Bosch unit at a local Napa Auto Parts. I would think it would be cheaper than dealer, but you never know.

After getting a jump start at work, I made my way to Autozone where they tested the battery and got a "Charge and Retest" message. They offered to charge it for me, but said I had to pull it and bring it inside. At 8 PM, I didn't feel like that was an option. I don't think they realized what was involved.

I picked up a load tester and tested the battery when I got home. It tested good at rest and marginal under load. The charging system tested OK.

I left it on the BMW cigarette lighter trickle charger overnight and locked it. I had 12.2V this morning and it started easily.

I'm going to bring it to the place where I purchased the battery for testing since they can replace it under warranty if it fails testing.

Plan for this weekend is to remove remaining third party electronics (except the Dension Ice Link) and perhaps fuse 74 if I can live without it (not sure if I'll be able to sync Bluetooth and use handsfree without 74).

Battery and charging system passed testing. The battery tested "GOOD - RECHARGE" at 12.28V and 744 CCA (rated 850 CCA). I plan to start the hunt for battery drains.

Yikes, I was hoping it was just going to be your battery or something else easier to diagnose than a drain. Good luck on the search. Isn't the final stage resistor a common drain issue?

Thanks for positive thoughts. You're right about the FSR, but I replaced it a couple years ago. Now on to reviewing the testing procedures for detecting battery drain.

I am having the same problem, battery goes dead whenever volts at 13.4 when running on dash. Have you figured yours out yet.