Do I Need a New Battery?

[IL8Apex]

Coming up 4 years in ownership. Today, all iDrive settings spontaneously reset to default. All stored radio stations disappeared. Equalizer settings reset to default. Both side mirrors reset to default.

No problems starting the car however, and clock is still accurate. Always use the same key so that's not the issue.

If it's the battery, how long do I have before I can't even start the car?

If not the battery, what's the problem?

[alee0729]

You're due for a battery whether or not this is causing your other problems... BMW batteries tend to go like clockwork every 4-5 yrs.

[bimdo]

and as they get weaker they start to shut down peripheral functions like the clock

[BIGW0RM]

Yes you do.

[CBS]

Sounds like you do. I just changed mine but my fault for not driving much and not using my battery tender.

[SWOT1]

Originally Posted by M3

My battery is about 5 years old or we can just say it is the actual battery that originally came with the car.

After getting symptoms like keyless entry not working, clock and other custom preferences kept on resetting, I scheduled to replace my battery. At the same time, I bought the battery tender plus from Walmart for future needs. Well, I decided to hook it up to my "nearly dead" battery to see how it works. Wasn't expecting to save the battery or anything, but here's how it went.

It stayed red, which means charging for nearly 12-14 hours. Then started blinking green, which means %80 charged and still charging for another 10-12 hours. Well, when I got home from work it was fully green. All the functions were back working on the car. I was really amazed and decided to cancel my appointment with the dealer and see how long this will actually last. It's been about two months or so and my battery is doing it's job flawlessly.

Oh and during the two months period, I hooked on my battery tender four times as I wasn't driving the car at all. Everytime I repeated this process it took less and less time. The last time I repeated this process it took 7 hours to be %100 full. Remember the car is sitting in my garage and not being driven at all.

So you might want to spend $50 on the Deltran battery tender before you spend $300-400 on a new battery. Your pick.

I’m in the same boat... 2009 E93 M3 with original battery and all the symptoms you described (keyless entry, clock...starting to malfunction.) I definitely think I’ll try the battery tender first. My question to those who have experience with battery tenders, is the Deltran the way to go or is there a preferred device for our M’s??

[SenorFunkyPants]

Sounds like a key fault...battery problems are normally indicated by fault messages on the idrive and the clock going slow...looks like the key has lost all its settings and reset the car to default.

[M3]

Originally Posted by SWOT1

I’m in the same boat... 2009 E93 M3 with original battery and all the symptoms you described (keyless entry, clock...starting to malfunction.) I definitely think I’ll try the battery tender first. My question to those who have experience with battery tenders, is the Deltran the way to go or is there a preferred device for our M’s??

Deltran Battery Tender Plus is what BMW sells as OEM.

http://www.walmart.com/ip/17688539?w...l5=pla&veh=sem

[dkkim]

I've got new battery under warranty a few weeks ago.
I had no welcome light, rear defroster and top control via key fob.
Also had several low charge level and battery discharge warnings.

[fuddman]

Sometimes, electrical problems stem from poor battery connections. I suggest cleaning your terminals, charge the battery and see what happens.

Could your car be part of this recall?: http://www.m3post.com/forums/showthread.php?t=804611

I have the battery tender plus, too and it works great. My battery was located quite a distance from the plug. So, to avoid using an extension cord, I bought 12 foot cable (made by the same company) which extends the battery clips cable.

[calintexas]

I have 2 Battery Tender Plus's. One is BMW branded and the other is Deltran branded. They work great. You can also get the Deltran on Amazon for about $45.00. A search on "battery tender" on this site will yield many threads where people talk about their issues with keeping the battery on their M3 charged. Whether it's due to power drain while the car is sitting or charging schemes that prioritize fuel economy over keeping the battery charged (or a combination of both), it's apparent that you have to drive an M3 a lot and over good distances to keep the battery fully charged.

You want to get a tender with the alligator clips as the power socket in the interior is not hot when the car isn't operating (key fob not inserted). The jumper terminals in the engine compartment are generally the best connection points.

With the fuel economy pressure on the auto manufacturers, I think keeping batteries charged will become more of an issue over time. We just bought a new CR-V. There's some weasel words in the manual about not using accessory power very much with the engine off. We have a friend that does in home physical therapy (the legitimate kind - degreed & licensed) that puts on lots of miles. She's had her CR-V for about a year and has started having battery trouble. As a result of her problems, I put our new CR-V on the battery tender. It took several hours to achieve a full charge, and now, even with driving it all the time, it takes about 4 hours for it to be fully charged when I hook the Battery Tender up to it after a few days. In the case of the CR-V, it appears to be a small battery (likely for both cost and weight) and a fuel mileage biased charging scheme.

[urBan_dK]

Didn't even need to read the first post, the answer is yes.

[darnelld]

yup.

[sensi09]

Originally Posted by IL8Apex

Coming up 4 years in ownership. Today, all iDrive settings spontaneously reset to default. All stored radio stations disappeared. Equalizer settings reset to default. Both side mirrors reset to default.

Had this happen a few times and settings came back after a restart.

Still on the current battery and this happened maybe a year or two ago.

[darnelld]

Had you let it sit for awhile when it occurred back then? I know that if I don't drive mine for an extended amount of time the battery will discharge resulting in odd behavior. After driving symptoms go away.

[Richbot]

I keep my car on a battery tender to keep the electronics happy if I am letting it sit for more than a week at a time. Low voltage when the car is "asleep" can really freak things out the next time you start

But it's a long way from a slow clock to a dead battery, the power management system starts shutting off power to various nonessentisl things in a low voltage situation to preserve starting capability, at least in theory. My car started fine for a month before I finally convinced the dealer the battery was going

[///M Power-Belgium]

Originally Posted by IL8Apex

Coming up 4 years in ownership. Today, all iDrive settings spontaneously reset to default. All stored radio stations disappeared. Equalizer settings reset to default. Both side mirrors reset to default.

No problems starting the car however, and clock is still accurate. Always use the same key so that's not the issue.

If it's the battery, how long do I have before I can't even start the car?

If not the battery, what's the problem?

I had the same problems , now she go's one day a week overnight on my CTEC battery tender and that every week....problem solved !

[crunchy_frog]

i have a 2008 392 m3 and i am still on the original battery. i have a ctek battery tender attached to the car once a week when i'm not using it. try using a battery tender first before replacing the battery