[r111]

I have an 2006 330i and I just installed my 3rd BMW battery 4-5 months ago on my own. The first battery lasted 2.5 years, and the second battery lasted 1.5 years. No faults, but 1 day I couldnt start the car.

Because I don't have a BT tool or know how to code, I skipped the registration piece.

has anyone tried registering the battery after so many months in use? Is there any reason to be concerned?

[Surly73]

In my opinion, this is a "better late than never" kind of situation.

You shouldn't be going through batteries that fast. Are you having them replaced just because "one day they don't start the car"? That may just mean they are discharged and/or not charging properly, not that their service life is over.

For what it's worth, I think the car only stores up to 4 battery replacements over the life of the car. Every time to register a battery it logs the odometer reading in a slot. I think there are only 4 or 5 slots. I don't know what happens when you try to register batteries beyond that.

By the way - this "registration" history is also an excellent way to verify if those shops who say they did it actually did. It can be viewed from INPA in the IBS screens along with other statistics like how long the battery has spent at various temperatures, voltages, states of charge etc...

[r111]

Thanks for the reply. I drive daily and on weekdays, I put in a (2) 50 mile drives to and from work. Every 6 months, I would put on a battery tender. The car would simply hesitate to start at least 1-2 times before it would not start up no charge with the tender.

I did the second and third battery install myself. Each time, I took in the failed battery to the dealer and bought a replacement with the same part number. Since the specs were the same, I risked on the second battery lasting as long as the first one.

1.5 years isn't a very long life. I was even hoping the BMW batteries would last at least 3-4 years. My sister's Benz has a factory AGM battery that's lasted 8 years of light driving.

I'm going to put the car on a battery tender again and take it to a shop that can register it for me. Good to know that car has limited registration slots.

[Surly73]

Originally Posted by r111

Thanks for the reply. I drive daily and on weekdays, I put in a (2) 50 mile drives to and from work. Every 6 months, I would put on a battery tender. The car would simply hesitate to start at least 1-2 times before it would not start up no charge with the tender.

I did the second and third battery install myself. Each time, I took in the failed battery to the dealer and bought a replacement with the same part number. Since the specs were the same, I risked on the second battery lasting as long as the first one.

1.5 years isn't a very long life. I was even hoping the BMW batteries would last at least 3-4 years. My sister's Benz has a factory AGM battery that's lasted 8 years of light driving.

I'm going to put the car on a battery tender again and take it to a shop that can register it for me. Good to know that car has limited registration slots.

Just for reference, I expect that my climate is tougher on batteries than yours. My 2007 E90 had around 60k miles when I bought it and it's original factory battery was fine. I noticed that cranking sounded a little laboured, but it turns out that seems to have nothing to do with the battery so it's now on my get-it-looked-at-before-the-extended-warranty-runs-out list.

I had a nearly new group 49 AGM battery on hand and I swapped out the original "just cause" and did all of the coding, programming and registering to do it properly.

My 5+ year old factory battery was still doing fine. A life of 1.5 years isn't just "short". Ever had the charging system checked? Lead-acid batteries begin to sulphate if they are kept at less than 80% charge (measured from a chemical standpoint) and sulphation kills batteries. If your battery isn't being charged up properly or if parasitic draw or "sleep" problems keep running it down then sulphation could be to blame. Your driving habits don't sound like the problem (unless perhaps you like to have the pre-programmed VENT function cool your car for 30 minutes every day without the engine running or something like that).

[r111]

I get what you are saying about parasitic loss. It'll be hard to find, but perhaps a check for error codes may help. I plan on getting a coding cable and install INPA NCSExpert within the month. I haven't had much time to review the coding pages, but it doesn't seem too bad.

I wonder if it's the alarm function that may drain the battery. I have a garage for overnight parking, but the alarm must drain something during the day.

[Surly73]

Originally Posted by r111

I get what you are saying about parasitic loss. It'll be hard to find, but perhaps a check for error codes may help. I plan on getting a coding cable and install INPA NCSExpert within the month. I haven't had much time to review the coding pages, but it doesn't seem too bad.

I wonder if it's the alarm function that may drain the battery. I have a garage for overnight parking, but the alarm must drain something during the day.

The usual way to find it is to hook instrumentation up to the car, wait for it to sleep, observe the sleep current and start pulling fuses until it looks in line with spec.

Now, if the car never sleeps (like more and more E9xs I'm hearing about this week) you can never do this. Similarly if the IBS is doing goofy things at the same time a real human is trying to test it. In theory, the IBS knows which of several circuit branches are drawing too much and is supposed to shut them down. A challenge for me is that I'm not sure if a non-IDrive car (like mine) gives the "battery drain" warnings on restart via CHECK CONTROL, or if non-iDrive owners just never know there's a problem without using INPA.

Anyone know?