We have a new/used 2003 525i with 75000 miles and we're trying to establish the age of the installed BMW battery. Maintainance records are scanty & show no battery replacement. Battery show "green eye" and seems fully functional but we suspect the battery to be the original. If so, the battery is nearing the battery burial ground. Can't find a date tag/stamp on battery. Forum, Is there a way to determine when the battery was manufactured? Thank you.
If you have a BMW battery, check the negative terminal and a production date will be stamped on top in week and year. (Ex. 52-99 would be the fourth week in December, 1999)
They last a long time... If you use it regularly and don't allow it to discharge then my experience with these batteries is that they will last a long time. I believe I had the original battery in my 96 740i and when I sold it 3 years ago after owning it for almost 10 yrs it was still working with no issues. That battery was probably 12 years old and at least 9.5 years old. I had to replace one in my wife's 2001 330i because it froze and cracked while the car was stored for the winter, ever since I make sure it is fully charged and take the negative terminal off when I put it under cover for the winter. My son's 1999 323 needed its battery replaced this year and I believe it was the original factory battery. Like I said, I think the OEM battery in these is superior to any battery I have ever used. Change it when it shows signs of wearing out... ie hard starting, or dying often. You can't let theses cars sit too long or the electronics in them will flatten the battery. A week is fine, more than that and you need to take precautions. Chuck
Chuck, Thanks for the reply. We've gotten 9 years out of the original batt in my wifes 200 Z-3. Replacement was another BMW unit. The batt in the 525i is 8 years old and we hope for 2 more. Both are maintained by a Battery Tender Plus. Non-BMW owners (the unenlightened) are amazed as the service life we get out of our batteries,
