[mwh2009]

We're going to the beach in a couple of weeks, and can't take my 340i because we have too many people.

I'm worried that the battery will die while I'm gone. What have others found when parking the car for 7/8 days? Is the battery capable of handling that?

I don't own a trickle charger and it seems crazy to buy one since this is my DD....

[Tyresian]

Your battery should be able to last a couple months without a charge. Granted our cars are known for having some battery issues in low temperatures, I've had issues with my car in the winter but that's when it was weeks of below freezing and sometimes sub 0 F.

During good weather I've traveled for work and left my car sit for a few weeks with no issue, ANY car should be able to last weeks for sure without issue.

[wrickem]

My cars all sit for 2-3 weeks while in "rotation" and there's never been a problem until they get old and need a routine battery replacement (4-5 years) anyway. Don't worry about it. It's fine for 7-8 days.

[Pauleebe]

A few weeks is fine, you do realize people take vacations lasting more than a few weeks at a time? I'd be more concerned if a few months. I'm sure BMW has some owner's manual literature on this topic for specific recommendations.

[89alpinem3]

As others have said 7-8 days is nothing your battery will be fine

[mwh2009]

Originally Posted by dwalls90

A few weeks is fine, you do realize people take vacations lasting more than a few weeks at a time? I'd be more concerned if a few months. I'm sure BMW has some owner's manual literature on this topic for specific recommendations.

While I do realize it, it's never happened to me. One day....

Thanks all for the input. I was concerned because the 12V ports in the car seem to be 'on' all the time even when ignition is off, and, I know that when locked, the car has some break-in sensors going, etc.

I've never had a problem in all my other cars, either. Never even thought about it as a matter of fact. But those were all Toyotas and Subarus, and I had a soundbite rattling around in my head from somewhere about BMW's having a bunch of always-on stuff that could drain the battery.

Thanks again... It's why i love this forum.

[Billfitz]

In summer a week or even two won't be a problem. I'd put it on a maintainer for longer than that. In winter I run a maintainer if temps are going below 20F or so and/or when it's going to sit more than a few days. The outlets aren't a problem, they shut off within ten minutes or so.

[floydarogers]

Originally Posted by Billfitz

In summer a week or even two won't be a problem. I'd put it on a maintainer for longer than that. In winter I run a maintainer if temps are going below 20F or so and/or when it's going to sit more than a few days. The outlets aren't a problem, they shut off within ten minutes or so.

+ This.

My wife and I just got back from 18 days in Europe, both E90 and F30 started no problems. I've gone longer - 4 weeks - with no problems. I wouldn't put a trickle charger on unless it's more than a month (or cold).

[Official NOCO]

You can find cheap trickle chargers if you end up in similar situation as this, but the weather is cold. Otherwise, like others have said, you're fine.

[ajob]

Your battery discharge question has a wider, less discussed issue.

The problem is not so much about leaving the car undriven for one week, but leaving it every night - sounds strange, but here's why: any battery has a certain reference number of full discharge cycles before "dying", say about one hundred full cycles or so.

As long as these are not of the bad "deep discharge" type, it matters little whether the cycles are divided in twelve undriven hours every night or 168 hours in one undriven week; it's all cumulative and unused cars still use significant battery power, increased 5 to 10 times if anti-theft trackers or webcams remain active.

That's why every time I park in the garage I hook up a good charger (a C-Teck set up for AGM batteries) and "stop the battery depletion clock"; the hook-up takes one minute and saves battery aging.

In some countries I hear that BMW batteries get changed early and for free at periodic services, but France does not seem so generous.

[Billfitz]

Originally Posted by ajob

any battery has a certain reference number of full discharge cycles before "dying", say about one hundred full cycles or so.

In warm weather over a period of even two weeks the battery discharge will be minimal. Climates like Switzerland will have far different battery issues than Monaco, especially in January.

[joshvt]

I work from home, live close to the city and don't drive a ton of miles. My last car, an e91 needed a battery replacement at 3 yrs/ 19k mikes. The dealer recommended a battery tender for for the same logic you describe. Not long after that my e91 was a victim of an accident. Now I am in a new f31 and guessing I will have the same issue. I live in NC and we get a fair amt of lightning storms. I have lost computer equipment even with surge protectors. Makes me nervous to leave my car connected, especially if I am traveling during summer months when storms are likely. Is this a reasonable concern?

[x5mad]

Anything under 4 weeks is fine.

If left in your garage make sure the car is locked so that the car shuts down properly.

[Blubaron79]

Umm. It will be fine. My 2009 sat for 6 months and didn't die.