I just returned from a one week vacation and my C300 started up just fine.

I'll be going on a two week trip, and wonder if the battery can sit idle for that length of time.

I've read on some web sites that because these newer vehicles have so many on-board computers the battery is constantly draining when parked. I've also read (on a Jaguar Forum) that locking the car shuts down most of the computers, but things like seat/mirror memory are still active.

 

I actually have the same question, as mine is about to sit for about a month...

 

Most cars can sit for a month without problems. If there's any doubt at all, pick up a battery tender and leave it plugged into one of the car's outlets. I have used CTEK products for years and think highly of them, but there are many good tenders around.

 

I've thought of that, but I'm thinking of leaving the car at the airport so that wouldn't be an option.

 

Two weeks will not be any problem, especially in warmer weather.

 

Memory chips take very little power to keep their contents.

 

As far as I know there is nothing in a manual about the battery being drained after the car is parked for an extended period of time. I don't see what could drain the battery, since only a few devices could be active, such as the clock and a few other low current devices.

I leave my car every year for up to two month and never had any problems, although admittedly not this one yet.

 

This is from the manual

Parking the vehicle for a long period
If you leave the vehicle parked for longer than
four weeks, the battery may be damaged by
exhaustive discharging and further damaged
in the event of this occurring again

This I can understand. One element maybe the parking brake. However, I doubt it discharge the battery while parked.

The below I can not

If you leave the vehicle parked for longer than
six weeks, the vehicle may suffer damage as a
result of lack of use.
X Visit a qualified specialist workshop and
seek advice.

 

Left my car sitting there for a little over two weeks just a week after buying it and it started up without any issues upon my return. You should be just fine.

 

Hmm..I haven't noticed that. Is it for real, or is it manufacturer covering his unmentionable?

My C300 was manufactured 2 months before I picked it up and it was driven no more than 20km. It was not demaged when I got it, I hope.

 

There's always a background drain from the PCM so, yes, the battery will slowly drain over time.

 

On my uncle's mercury grand marquis and s550 he unplugs the battery from the car.

 

The question is, how long it will take to really drain the battery entirely? And, is it any faster than in the previous models?

 

With all the CANBus hibernation techniques used by Benz the vehicle will probably still start after 3 months of standing. Benz is covering their butts because if voltage drops too low a whole lot if things need to be resynched due to memory loss. Things like HVAC, Windows, Sunroof etc. etc. Why auto manufacturers are still using volatile memory chips in this day & age I do not understand.

No real Damage will be done. Tyre flat spots will be relieved by some driving etc.

As for total battery drain it is very dependent on battery condition & some variability relating to ambient temperatures etc. etc.. Benz genuine AGM batteries hold charge very well at slow discharge rates. Battery damage is unfortunately possible if repeatedly pushed too far.

If you live by Benz recommendations you will be safe as houses because they will be covering their behinds & taking extremes of temperature etc. into account.

 

I have left my car for a month at home while I was overseas and it didn't have any problems. It's a 2014 E class. I think you should be perfectly fine leaving your car for 2 weeks or even longer. Don't sweat the small stuff.