[Lotus99]

My car's a 2008 335i E93, and has a black battery in it, which I have read means it is AGM, vs. a lead acid battery that is supposed to be white. I'm surprised, because I wouldn't have expected it to be AGM as I thought most of the older cars had lead acid.

I bought the car back in mid 2008, so it's just over seven years old. It only has 40,000 miles on it though, but it's my DD all year long.

When I look up either of the two part numbers, to double check if it is in fact AGM, neither show up strangely enough...

AGM should last longer than lead acid from what I had understood, but would 7 years be a good time to replace it anyway?

I've had a few odd things happen with the Comfort Access doors not locking as quick as they used to, and reading that you start getting weird electrical gremlins when your battery is dying, I'm wondering if I should just proactively replace it?
.

[328skidpad]

2008 335 bought new lasted 7 years...

[Lotus99]

And how did you know it was time to replace it?

[TrAcK TRaP]

Originally Posted by Lotus99

And how did you know it was time to replace it?

+1 I wanna know as well.. 04/07 here still original battery..

[BMWs4ever]

Originally Posted by N54CherryHill

+1 I wanna know as well.. 04/07 here still original battery..

I have an original 07/07 too as I bought the car new. Mine is still running good but I'm beginning to wonder since next year it will be 9 years old

[1QuikWS6]

92Ah AGM in my 09' 328 - lasted 4 yrs

Dealer replaced for free under warranty

Everything about the car was fine except I was getting a constant re-occurring '2DEB' Power Management code at time of replacement. Battery was checked & found to be weak

[Gmanuel]

My original battery lasted until earlier this year; about 8 years, and 80k miles. It was a white top too, which makes it even more impressive. Yes, you do start to get little gremlins when the battery is about to go kaput; my side mirrors would aim at the ground when in reverse, but would not come back up after, and I would randomly lose (then they would come back a day or so later) my radio presets as well.

[mike-y]

2006.

replaced mine about 3 months ago due to slow cranks. couldn't tell what it was until I took it out of the car and saw the "Pb" marker on it.

[cdgatti]

Originally Posted by Gmanuel

My original battery lasted until earlier this year; about 8 years, and 80k miles. It was a white top too, which makes it even more impressive. Yes, you do start to get little gremlins when the battery is about to go kaput; my side mirrors would aim at the ground when in reverse, but would not come back up after, and I would randomly lose (then they would come back a day or so later) my radio presets as well.

+1 the gremlins will let you know time for a battery and don't forget about the reset coding even if you replace with like for like.

my 08 lasted 6.5 years. non-agm, but put in an agm diehard from sears, all electricals flawless now.

[ctuna]

Can't play the stereo longer than 10 minutes while the
car is sitting with the engine off.
Slow cranks that and it takes a long time to start.
This usually happens on the first start of the day.
New battery starts up almost right away snappily.

[ferocity02]

2007 335i, 89k miles, still on the original battery. But it's on borrowed time. The comfort access sometimes stops working as well as the rear defroster. Now I try to keep it on a tender if I don't drive it for more than a few days and it's been fine.

[Lotus99]

Originally Posted by ferocity02

2007 335i, 89k miles, still on the original battery. But it's on borrowed time. The comfort access sometimes stops working as well as the rear defroster. Now I try to keep it on a tender if I don't drive it for more than a few days and it's been fine.

Hmmm... I am now hoping my comfort access problems will be related to the battery. I have a heckuva time in the past year locking (but not unlocking) using comfort access, and a lot of times, in the car even, I get the "key missing" symbol on the dash. I'm hoping it's not the comfort access module itself that is acting up.

[Wilt]

Originally Posted by Lotus99

Hmmm... I am now hoping my comfort access problems will be related to the battery. I have a heckuva time in the past year locking (but not unlocking) using comfort access, and a lot of times, in the car even, I get the "key missing" symbol on the dash. I'm hoping it's not the comfort access module itself that is acting up.

Have you tried replacing the 2032 button cell in the CA fob?

[Lotus99]

Originally Posted by Wilt

Have you tried replacing the 2032 button cell in the CA fob?

Yeah, First thing I tried. I have tried both keys, and they are the same. I have replaced the battery a couple of times even in my key fob, and it made no difference.

Locking is quite difficult, and takes multiple attempts. It’s the same on both sides of the car. (I haven’t noticed it as much on the trunk). But unlocking is never a problem.

And sometimes when I am in the car, and press the Start button, I get the warning on the dash that the key cannot be found. I leave the key in my man-bag, so if I move the bag a bit, and try again, it recognizes the key.

Hoping it's not the freakin' CA module...

[roadkillrob]

got my car new 11/2007 just replaced battery a few months ago when it wasn't lasting as long on battery when I was programming it one day - so 7.5 years and wasn't totally done yet.

[Miller335]

My June 2007 335 still has original battery, still going strong.

[SpeedBuggy]

2006 330i 43,000 miles, 08/06 build date still on original battery
2006 3251 100,000 miles, 07/05 build date battery replaced in 2011 (slow crank)
2007 328xi 116,000 miles, 09/06 build date battery replaced in 2012 (slow crank)

[lookalikehuuh]

2006 330i build 09/06 still on original battery.

***knock on wood***

[hassmaschine]

unless you are having problems, I wouldn't replace it.

the battery on our 2006 E91 is original. I'll probably replace it within the next year since the cold cranks aren't great, but it's fine otherwise. I can't recall if my 330i has been replaced or not but I suspect it has.

[John 070]

Originally Posted by SpeedBuggy

2006 330i 43,000 miles, 08/06 build date still on original battery
2006 3251 100,000 miles, 07/05 build date battery replaced in 2011 (slow crank)
2007 328xi 116,000 miles, 09/06 build date battery replaced in 2012 (slow crank)

Wife's aunt's 330 is 6 mos. older than yours, original battery 50k miles.

Makes me look very foolish replacing mine at 5 yrs. just because. Have to admit, dealer told me I didn't need it. That's $280 I can't get back lol

[John 070]

Originally Posted by hassmaschine

unless you are having problems, I wouldn't replace it.

exactly, that's what a load test is for. I learned the hard way because I insisted it be replaced at 5 yrs., just because the scary battery icon appeared one day when it was cold and I was listening to tunes in the car (in reality, that was because my car sits weeks in the garage undriven)

[jt335i]

My OEM batt lasted 5 years, 7 months, 21 days!