I'll throw this out. 12 neg system. That means current flows through the ground. This is why you remove the ground first on car batteries. Try some thing simple, take a set of jumpers from the negative post a solid ground adding a parallel path to your ground. Beyond this, if you have the cheap Autozone red battery. Move on, they only last a few years before the system is taxed

my input on this is yup damn misleading dash indicator albeit on another bmw, cos we went out and swapped out battery straight away BUT turns out (and have had car back 2 days now, so far so good) the voltage regulator, (tensioner) pulley which had slack

quick update:

Got the battery load tested and it checked out 100% according to the tester at Autozone. ...So now i have a brand new alternator and a confirmed good BMW battery. At this point, I am planning on changing out the ignition switch next and really hoping that takes care of the problem. I'm thinking that since I have been having intermittent 'no starter engage' issues and these strange electrical system warnings that this might be a good next step. Plus, there was a reply to a post of mine on another forum in which another X5 owner was experiencing similar symptoms to mine that were cured with a new ignition switch. If any of you have any other ideas I'm all ears. :D This is quite frustrating.

Thanks-

Try the battery first because the switch has contact points that get burned out,there both a easy fix . You can take the switch apart and clean it and sand it down just to see if its burnt .

RESOLVED!!!
 

Hey everyone, I wanted to post and let you know the problem has finally been resolved. I changed the ignition switch and everything is back to normal. No more flickering battery light, no more flickering PDC light, no more pulsing compass display, no more intermittent starting in cold weather, etc.

Of course, while I was still waiting on my new ignition switch to arrive in the mail, the X5 went into failsafe mode on the way home from work while I was doing 75 on the interstate and shut off completely. About 5-10 minutes before this happened the battery light started flickering and then went solid red. I knew something had suddenly gotten worse... The traffic was heavy (rush hour) and fortunately I had just enough momentum to weave through traffic to work my way over to the shoulder. I could not get it restarted to save my life. To add insult to injury, it was dark and raining cats & dogs. I had to finally relent and call the tow truck to get her towed home.

Moral of the story: If left undetected long enough, a failing ignition switch CAN leave you stranded. :(

The other moral of the story: Evidently what can appear to be symptoms of a failing alternator/battery can actually be the ignition switch in disguise. If you have a flickering battery light and your alternator appears to be charging properly and your battery is testing good, it could be the switch. In any case, I hope this thread will help somebody who might be chasing down a similar problem. Thanks everyone for your feedback and replies, especially the info regarding unlocking the OBC and monitoring voltage. It was a huge help in trying to figure all of this out.

Thanks for posting the fixed to your problem. It should help other people with a similar problem.