how tell if battery is dying?

[tranquility]

Btw, I don't have idrive.

I'm at 6 years and read that is about when the original battery dies? Is this about right? Are there any clear signs it's dying or will it just happen and I'll be SOL?

Just the other day my settings reset (e.g. turn signals set to 3 blinks reverted back to 1), is that a sign?

Finally, I can only do a replacement at a dealer since it's a complicated install? How much is the cost?

Thanks!

[jparnes1]

To really know you need to check with a voltmeter. A fully charged battery is going to show about 14V. Below 12 V you need a new one. It's not difficult to install at all but you have to register the battery with the ECU. Lots of apps out there to do this (Carly, for one). If you buy the battery at BMW and have them register it, it could be around $4-500.

[NoQuarter]

The biggest tell-tell sign is your clock. When your clock no longer keeps the time then get the battery replaced.

That said, if you are going into the winter months, at 6 years old I would replace the battery.

You can also take it to just about any auto parts store and they can do a proper load test on it free and tell you if it is any good.

[Mick70]

Funny story - this is how I found out that my Z4's battery was dying:

My Z4 has started last month going into limp mode and throwing various strange error codes, all referring to throttle valve and intake (2CF6, 2CF7, 2D2E), this happened almost daily.

So I read a lot and tried to find a possible solution without bothering the dealer. Strange enough, at first I did not find a clear solution that seemed to help at least in a relevant number of cases. All common proposals, such as replacement of throttle head, pressure tests, control of ECU wiring harness etc., were to no avail in almost every case on E90post.com, n54tech.com and several other forums.

Finally I found a sidenote in a German forum that the E85's (!) ECU was very delicate in case of voltage fluctuations that may appear if the battery isn't the best anymore and a high load is switched on (e.g. headlights, roof mechanism, electric steering). Indeed, I could bring the error messages in connection with such events (e.g. entering an underground car park, driving in dusk, closing the roof while parking the car).

So I simply replaced the battery with a new Varta AGM 70Ah/760A battery from Amazon and registered the battery to the car with Mycarly. No problems ever since (3 weeks now).

BTW: The clock was still fine. But the battery voltage immediately dropped from 12,5V to 11,8V when engaging the central lock system...

Costs:
- Battery: 140€ ~ 156USD on Amazon
- Additional inapp Purchase in Mycarly: 10€ ~ 11USD. Of course you don't need the app at all if you have INPA or Rheingold.

Best regards

Mick

[NoQuarter]

Good to know Mick. Thanks for the post.

I have not had my E89 long enough to have a battery problem. My experience has been on 3 and 5 series demonstrating with the clock problem first.

Now I just have to remember to think of this if my ECU starts getting random problems!

Cheers!

[Mick70]

[fifthdawn]

Well, I always get "Increase battery discharge" whenever I start the car no matter how long I've been driving. Been having that for like 2 months but it still starts up and runs fine everytime.

My comfort access starts to not work overnight. I works if I manually unlock it. It'll work for a couple hours.

Whenever I unlock it from overnight, I hear a sound like its powering up, cant explain it. It seems like maybe the car is low on battery so overnight it goes into a deeper sleep and wakes up when I manually unlock it.

I would say these are probably sign that the battery is going soon. I'll probably need it replaced before winter comes.

[kosd]

I believe the noise you hear when unlocking from overnight is the Hp fuel pump priming and is normal for our vehicles.

[NoQuarter]

Yep. That sound on unlocking is the car just getting ready to be awesome when you start it up. Don't worry about that one.

The increased battery discharge could be a sign that something is indeed killing the battery when it shouldn't be, but I would not go there yet.

If the car is not a daily driver, long trips, etc so the battery can fully charge, it can get pretty weak.

start with charging it up with a battery charger using the terminal posts under the hood/bonnet of the car (not directly to the battery in the trunk/boot).

Troubleshoot only after you know you have a fully charged battery. You don't want to go buy a new battery then have it discharged from an errant electronic gremlin.

[tranquility]

Tx for all your input, guys. Darn, I wish there was a simple meter or something clear-cut. It's my only car and I daily it, so the battery's pretty strong (knock wood) and I try to be smart about things, e.g. engine's running when using the roof, etc.

I'm not adept at using apps, so probably will have somebody else do the install. Sounds too complicated for me lol.

I can get it checked out for free anywhere, even at the dealer?

[NoQuarter]

Don't count on the dealer to do anything free but certainly call and ask.

[fifthdawn]

Originally Posted by NoQuarter

Yep. That sound on unlocking is the car just getting ready to be awesome when you start it up. Don't worry about that one.

The increased battery discharge could be a sign that something is indeed killing the battery when it shouldn't be, but I would not go there yet.

If the car is not a daily driver, long trips, etc so the battery can fully charge, it can get pretty weak.

start with charging it up with a battery charger using the terminal posts under the hood/bonnet of the car (not directly to the battery in the trunk/boot).

Troubleshoot only after you know you have a fully charged battery. You don't want to go buy a new battery then have it discharged from an errant electronic gremlin.

Oh, interesting. If you hadn't mentioned, I would have tried to charge it from the trunk.

I've never seen a terminal post for charging battery before. Is there a picture somewhere on its location?

With that said, if I need a jump or to jump a car, would I use the terminal post as well?

[jparnes1]

Look in the engine bay near the rear firewall. There's a red plastic cap. Pull it up - that's your positive. The negative is over on the left (as you're looking at it) strut mount area. It looks like a bare metal rod sticking out sideways. Or use any spot of unpainted metal.

[jparnes1]

Originally Posted by tranquility

Tx for all your input, guys. Darn, I wish there was a simple meter or something clear-cut. It's my only car and I daily it, so the battery's pretty strong (knock wood) and I try to be smart about things, e.g. engine's running when using the roof, etc.

I'm not adept at using apps, so probably will have somebody else do the install. Sounds too complicated for me lol.

I can get it checked out for free anywhere, even at the dealer?

There is a "simple meter". Like I said, get a volt meter and check your charge. It couldn't be easier.

[tranquility]

Originally Posted by jparnes1

There is a "simple meter". Like I said, get a volt meter and check your charge. It couldn't be easier.

Like this?

Are there any settings on the volt meter or just touch the battery's terminals?

[jparnes1]

Yeah that's it. Just set your voltmeter dial to the 20V setting. Also check the battery in the morning after it's had a chance to discharge overnight.

[tranquility]

Originally Posted by jparnes1

Yeah that's it. Just set your voltmeter dial to the 20V setting. Also check the battery in the morning after it's had a chance to discharge overnight.

Tx, man. Why do I need to set it to 20v? Would it give an off reading otherwise?

[SpikeMilligan]

Originally Posted by kosd

I believe the noise you hear when unlocking from overnight is the Hp fuel pump priming and is normal for our vehicles.

I think that's actually the low-pressure (lp) fuel pump inside the gas tank. The sound I hear on unlocking seems to be coming from behind the seats. The high-pressure (hp) pump is under the hood, attached to the engine.

[NoQuarter]

Originally Posted by SpikeMilligan

I think that's actually the low-pressure (lp) fuel pump inside the gas tank. The sound I hear on unlocking seems to be coming from behind the seats. The high-pressure (hp) pump is under the hood, attached to the engine.

Agreed

[tranquility]

My dealer was nice enough to do a free battery check. Apparently, they said that the voltage was not the main factor as the reading should be above 12V (mine was 12.39V). Rather, they said the key is CCA, a full battery is 800 and mine is 463, so just over 50%.

How long would you guys wait before getting a new battery given these readings?

[Tangent]

I'd replace that as soon as I could. With batteries there's no way to tell if once it starts failing if it'll last another several months or completely die the next time you try to start the car.

[rking117]

<funny> when it wont crank </funny>