Well, the battery on my '07 M Coupe seems to be unable to hold much of a charge. I’ve had the car for around one month and have not forgotten the lights on. The dealer said that BWM won’t replace batteries as part of the service agreement because many of these cars have batteries go bad due to salespeople forgetting the lights on in cars on the lot too many times (and the battery loses the ability to hold a charge).

This is a pretty lame policy since it sounds like BMW have figured out how to nickel-and-dime their customers on their so-called four-year maintenance policy. However, I don’t really feel like fighting the dealer on this issue.

I was quoted a price of about $270. Since I’ll be paying for this out of pocket, are there any non-OEM batteries that I should consider?

Go to a different dealership.

They already admitted that their sale staff is to blame so they should replace it.

Don't all Zs have auto lights?

Interstate is a popular and less expensive replacement. But first month of ownership? They darned well ought to replace it, just for the good will, if nothing else. Calmly reason with them, rather than jumping up and down and waving your arms.

FWIW, I've had my MC since June '06 and I've had my battery replaced twice at the dealership. They still can't find what's drawing on it, but they replaced it under warranty or on good faith anyway...

I've had my battery die once, the dealer said that it was related to a software update needed as an accessory was still drawing power when the car was off.

So far no issues.

BMW is definitely liable for this problem.

There is a recall regarding Bluetooth draining battery when you stopped engine being in a call. Interesting, that Mercedes has all time Bluetooth available, but doesn't issue any draining battery. Anyway I believe that battery can be fully charged after draining, so it is fixable problem, unless a battery is defective.

Well, the battery on my '07 M Coupe seems to be unable to hold much of a charge. I’ve had the car for around one month and have not forgotten the lights on. The dealer said that BWM won’t replace batteries as part of the service agreement because many of these cars have batteries go bad due to salespeople forgetting the lights on in cars on the lot too many times (and the battery loses the ability to hold a charge).

This is a pretty lame policy since it sounds like BMW have figured out how to nickel-and-dime their customers on their so-called four-year maintenance policy. However, I don’t really feel like fighting the dealer on this issue.

I was quoted a price of about $270. Since I’ll be paying for this out of pocket, are there any non-OEM batteries that I should consider?

Uhhhh doesn't that mean the dealership should eat the cost. I'd fight them on it. That is bull if they admit that it was their bad but they won't replace it.

My battery will be pretty drained after sitting for just 3 days, but will still start it albiet slower than normal. It's not the bluetooth either, I don't shut it off when I'm on a call, but I did try that and it will stay on and drain the battery if you do that. I think your battery should hold a charge if you put a trickle charger on it without having to replace it. You should try that 1st for all you know your next battery will drain too. Seems alot of Z4's have battery issues, I am going to get a trickle charger here soon.

With the battery being in the trunk, I bet we'll have to replace them earlier than most cars due to the longer run to the starter.

Uh... if anything the battery should last longer when it is in the trunk because it is not exposed to the heat from the engine compartment. BMWs have had their batteries in the trunk since the mid 80s I believe.

With the battery being in the trunk, I bet we'll have to replace them earlier than most cars due to the longer run to the starter.

You would only get voltage drop if the cables were sized improperly.

You would only get voltage drop if the cables were sized improperly.

+1 The longer they run the thicker gauge the cable should be but no other downside.

I’ve gotten some pretty good feedback on this thread—thanks.

I made an appointment with the dealer for the 24th to have the 1200 mile service and to get whole charging system tested. I’ll see if I can reason with them if it turns out to be the battery (which I’m pretty sure it is). I’ll let you know how it goes.

FWIW, I've had my MC since June '06 and I've had my battery replaced twice at the dealership. They still can't find what's drawing on it
If only there was some device that could be inserted inline and measure current... :D

I just had my battery replaced under warranty as well. BMW has had some problems with the 'glass-mat' type battery used exclusively in the MZ4 and the 7 series cars interestingly enough.

The dealer has zero ground to deny a warranty claim on a non-wear related problem.

The most probable reason is that the M coupe sat at the dealership for 200 or so days without ever being touched...... the reason i say that is because that just happenned to the M coupe I bought 3 weeks ago.....I noticed that the car had been on the lot for 274 days, they had to charge the battery when i bought it.... I took it home, let it sit in the driveway for a week and the battery was dead..... took it to the dealer and they replaced it ...... no charge....... call your dealer and tell them to replace the battery ASAP... you shouldnt have to pay a penny for anything you didnt cause on that car.....

I JUST replaced my battery after 5 years of use, and the previous owner who drove it for 5,000 miles a year for 3 1/2 years. I'd say they last quite some time in the trunk.

I agree on it being a dealer problem

Slight tangent. $270 is a lot for a battery. You can buy one of the best gel pack (Orbital/Optima)batteries for half of that. It didn't look like there would be a problem using one of these aftermarket batteries. Is there any reason these would not work, like BMW made the design so only their batteries would work?

Is the BMW battery better than the others? and if so how?