Will be leaving my car at the airport for around 4 weeks on a secure site.
Often hear about battery drain due to thing like can buses suffering fom insomnia ect.
But when the electrical system is on a problem free standby there will still be some form of drain of some kind.
With this in mind I wondered if anyone has actually disabled the alarm by locking the doors manually (Driver door with the mechanical key)
to save whats probably the most obvious amp user when your car is parked up for 3 or 4 weeks.
Be interesting to know your thoughts.
As said secure sight, sub zero temperatures likely, and wanting to maintain a decent cranking capacity on my return.
Many Thanks guys.

 

buy and keep a jump box in the car if your that worried about it.

 

Agreed i would keep a portable jump starter in the car


I don't think that just failing to arm the alarm will prevent battery drain - I don't arm the alarm in my garage but the battery will still drain after several weeks

You can get a battery brain t3 on Amazon which is a keyfob controlled battery disconnect , to completely cut all power drain

 

Don't know the answer.

However, if this secure site is used for long term storage I would be very very surprised if they didn't have a method of starting cars with flat batteries.

 

Many thanks for the replies guys.
I actually have an Audew 16800mAh 12v 800A peak jump start unit that I recently purchased from Amazon specifically for this reason.
Problem is a good friend of mine who is in the motor trade, said there are 2 top end vehicles he would never risk using one of these portable jump start devices on Top end Mercedes and top end BMWs.
He reckons the units have an open circuit voltage of around 15.4v.
This drops to around 12.2v whilst cranking, but said its what happens to your ecu's and canbus in the short time between wake up (ignition on) and cranking the engine to start !!
He said he has seen some expensive repairs needed, just by using such units !!
I also have a solar powered unit which connects to the OBD2 port just under the dash, and connects directly to the battery via the permanent 12v feed directly to the battery through the relevant port pins.
Felt that may be a better/safer option, just to help reduce any drain, and keep things topped up.
has anyone actually used a portable pack as suggested on the S Class ?
I would appreciate your experiences with these units and if there are any issues using them, as opposed to horror stories and chinese whisper type feedback. Is there any truth in what my friend says ???
Thanks for your input.

 

Lubricate the key lock on the trunk, the use it to open the trunk several times.

Try locking the doors manually, then manually opening the trunk and disconnecting the battery. Close the trunk and let it sit overnight. pen the trunk with the key, connect the battery, and see what problems you have.

If that is a safe and relatively easy solution, decide whether you want to do that manually, or if you want to install tusabes' remote disconnect.

 

I have an 06 s430 with the original Mercedes battery, 110k mi on her... I drive a semi over the road for a living and my car sits 2-6 weeks at a time I Chicago year round without being driven, even at -15F after sitting for weeks, I have no problems starting. Just make absolutely sure you turn everything off. EVERYTHING. If you aren't going to be gone for more than maybe 2 weeks or so and you have a good healthy, high quality AGM battery like the car is supposed to have, you should be fine. But still, you should always carry a jump box, I carry a full break down kit with me in mine because I'm usually hundreds if not thousands of miles away from home with mine. I always carry extra fuel, proper oils and greases, proper coolant, air compressor, at least what I call basic tools, the stuff for replacing fuses, changing belts, pretty much anything for any nut or bolt on the car, I carry with me. I've yet to actually have one of my own vehicles break down on me. It's all about the maintainence. Always be prepared.

 

I might also add, my truck runs constantly and ends up having to be jump started after a couple days, I know Mercedes are pretty tough and reliable when properly cared for... I know, alt capacity and all, but this car is able to jump a dead semi inside of 5 minutes. They're absolute beasts.

 

Yes it is very true many Mercedes have been damaged by improper jump starting

Usually it's a result of incorrect connection , using jumper cables connected to another car, or cables hitting the metal car body .

The small portable jump packs , if properly connected, should not cause a problem . I've personally used them several times on my w220 and w215. Note however I use a jnc660 which is a full size jump pack , not the small lithium ion jump packs . They may not be strong enough

 

Once again many thanks for your comments.
Over the years I have collected a number of start devices. I have an 800A booster pack which is pretty lumpy but works. I also have a recent Auduw 800A booster pack which is a lot smaller and lighter, so will deffo be keeping it in the boot. The battery in the car is brand new and made by Varta (Its the silver 100Ah version) which is supposed to be as good as any OEM battery, less a Merc sticker of couse.
Not expecting any problems after a 4 week lay up but just wanted to be prepared.
Thanks again, and safe motoring.

 

You should keep it in the center console or glove box as it can be difficult to get into the boot /trunk without power, those lithium ion jump packs are small enough

If you do have a problem getting into the boot, you can use the jump pack under the floor