About 4 months ago I started having problem with my BMW not starting up whe I come out in the morning or after work or somethong like that. I thought It was a low cell in my battery or the life of the battery. Everytime this happens I gety a jump for the battery and it starts right away and holds the charge for a few weeks infact, then the process starts all over again after the few weeks. I decided to buy a new battery a few weeks back and everything seemd to be ok, I was also told that if could be a eletrical timing inside the altenator that is going bad or somethng like that. Anyway yesterday I went to start my car up and It started agin with not starting and needing a jump. I've checked all my compenents on my car and I do not see anything that is running down my battery, I have no special stereos, dvd players fuses or nothing of a sort. I have a yellow wire attached to my + battery terminal and found out that belonged to the air bag detector for the passenger side. And also there is a thick red wire attached to the + terminal as well, but not sure were it leads all of these cant be drawing bad power from the battery because it was manufactured like that. No lights or left on inside or out I check this out all the time and just a bit of more info my check engine light came on before this started happening and I went to Auto Zone and they plugged up their machine and said that it was an emissions code. So I guess I did not clsoe the gas cap tight enough. By anyhow I do not think they are related in anyway even though I started experienceing these starting issues soon after. Hopefully someone out there has had these type of problems with their BMW, I've researched this problem on the internet and I've seen tons of possible causes but I need a close to definite answer so I'm not spending thousands of dollars running a simple problem down. If anyone can help and has a clue please let me know I struggling over here to know why this is happening.