[mabman]

I’m still on the original battery on my (April) 2007 335xi with about 150k km.
During the past month (with several days or a week between messages) I’ve had the message battery charge low display 3 times. I can’t remember the exact wording but it was something like that. It also doesn’t display in the system messages (that stay permanent until the condition is cleared/fixed) when I later go and check there – it says all OK – ie. no error messages. The car always starts without problem during these 3 incidents and at any time in fact – I’ve never had a battery problem all thru my nearly 10 years of ownership.

My question is, given the car is about 10 years old, should replacing the battery be done preemptively - ie. before it dies, like you should do with the water pump ?

I don’t venture much outside the city and always carry booster cables in the trunk so if the battery should die I’m just a phone call to CAA away from getting it going again and then replace it.
Besides inconvenience, is there any damage that can be done by having it die and then replacing it as opposed to replacing it now ?
I’m thinking with the 3 battery low messages in the past month it’s giving me early warning that it’s on its last legs.

Thanks for your advice!

[6ixSpd]

OEM batteries are recommended to be replaced every 5 years or so. Ten years is definitely way past the average E9X battery life.

[mabman]

I found a great post http://www.e90post.com/forums/showth...hlight=battery that discusses the exact battery problem I'm having. I failed to mention that my comfort access keyfob stopped working about a week ago while the car was sleeping. I could depress the buttons on the fob (as opposed to just touching the door handle) which would open the door locks and could then use the comfort access to lock the doors once I shut off the ignition and exited the car (as the car had been runnning and wasn't in sleep mode anymore).
Anyways, for future readers of my posted question, please also review the above post for other useful info.

[marcvtec]

Nah wait another 10 more years!
Just add some fresh lake water in it to top it up.

[Nick.B]

It could be a sign it's going to go in the next month, or year, or two. Hard to say exactly.

My brother just picked up a 2006/05 built 330 with the original battery. I had to jump it to even test drive it. Replaced the battery and all is fine.

My wife's 2006/01 built 330 had the battery replaced at some point before we got it this summer. Aftermarket sealed lead acid. The VO is correct, the CAS coding is correct, the car starts really well, but if you leave the door open for a minute or two it flashes a low battery warning. It has not been a problem.

[blackturbo]

Ten years is way pass over due, you got really good use out it. Mine was at 8 years and finally gave up.

Recommended change is 5 years

[F30-3'ER]

Battery should be changed every 5 years. I also have a 2007 build. Was having similar issues. Changed battery, problem solved

[Ali-E90]

I changed my 2007 battery in 2015

[Crankshaft Motorsports]

Mine is now 10 years old too. Definitely time to change and I am doing mine this or next week. Starts fine, but if you leave the key in the ignition too long w/o running the engine, it beeps. Also rear defroster is not working d/t the battery state of health.
Did you go OEM or what to replace?