[fanatic]

The other day my 06 E90 wouldn't start when I tried to leave work. No warning signs leading up to this and the only error that showed up on the dash was the clock with 0:00:00. Luckily I got a jump from my boss and made it home without any further problems. Next day tried to start the car and same problem.

Do I have a dead battery? If so, why doesn't the battery warning sign come on? Please help before I spend $200 on a battery I don't need.

[Welcome to NBA Jam]

Yes, that's a dead battery.

- Clock reset
- Required a jump

Classic battery symptoms. Go to AutoZone and ask to test your battery. Sometimes you can just charge it and it'll be good for a while.

After charging, listen to how the starter sounds over time. If it struggles to crank days after charging, dash lights get dimmer than usual during crank, you get odd dash errors, or any combination of those after you've charged it and driven for a month, you should get a new battery.

[fanatic]

Thanks! It just caught me by surprise that the battery warning light never came on.

I was ready to buy a new battery, as this is still the original battery for a car that is 10yrs old and 147k km logged on it, but I wanted to get some feedback in case it was something else.

[Welcome to NBA Jam]

Ah. 10 years is good! I'd say you got your money's worth. Probably a good idea to get a new one; you may be able to squeeze a few months out of it, but there's a higher likelihood you'd find it dead (especially if it's cold).

The battery light sometimes can come on during low battery scenarios, but most of the time it is because of a charging system or alternator problem.

[John 070]

I saw Walmart batteries for $117 usd....yesterday

[Wilt]

Get a battery which A) has the same RC rating and B) is the same type (flooded vs. AGM) or you will need to having coding done so that the electrical management module properly manages battery recharge, electrical consumption, etc.

Simply blindly buying 'a Walmart battery' is potentially asking for trouble unless you KNOW its characteristics match the existing battery.

[fanatic]

Matching BMW battery RC is pretty tough as they are exceptionally high. My OE battery is CCA 640 and RC 140. Most of the batteries that I've found are ACC 730/760 and only an RC 120. I guess I will have to live with having better starts and just be cautious of running the stereo while the engine is off.

BTW found a Kirkland brand (at Costco of course) for CDN$117 (CCA 730 RC 115). That's the one I'll probably go with.

[Miller335]

Not sure some people try to fight not getting an OEM battery over $50-$100 more out of pocket.

My original battery was almost 9 YO before it was killed by a repair shop constantly starting the car and shutting it off just to move it around the shop a ton of times over the course of two months.