Avoid Flat Battery whilst at Airport (W211)

[Brian WH]

Thats not strictly true, the battery disconnect issue has been blown out of proportion a fair bit by many people on many site's.

All of the car's vital data is stored in EEPROM and will survive for many years without battery power, disconnecting the battery will not put you in a tow to dealer situation and is at most an inconvenience.

That been said it is pointless in this situation, one good battery will do the job fine so 2 alright battery's won't have any issue, we have had car's of this vintage on the lot's for month's and they fire right up.

Probably the only good thing to come from an otherwise stupid redundant battery system

I agree it is not strictly true, but not recommended to someone who doesn't have access to a Star machine to reset those items affected, or the expertise to carry out the resets.

No it will not put you in a tow situation, but that is not the issue here. What was said was - that it is not recommended and you WILL have problems resetting items - as the person concerned will just make more problems than leaving it connected.

The advantage of two batteries is that it will more readily start, as auxiliaries are disconnected, thus putting what power is left into starting the engine.

 

[ANP320]

Sorry if a FAQ...

I'll soon be leaving my 2003 W211 E320CDI at Gatwick for 2 weeks in the long term. And again later in the year for just one week.


I know that aircraft fly very low over the car parks at Gatwick (South I think but may also be North) and have a habit of triggering car alarms. I think you can turn off the "tow away" alarm, which might be a good idea if yours is particularly sensitive.

That said, I've never had a problem leaving my car at Gatwick and I am sure you would be Ok for a couple of weeks.

 

[DansSlk]

I agree it is not strictly true, but not recommended to someone who doesn't have access to a Star machine to reset those items affected, or the expertise to carry out the resets.

You don't need any form of diagnostic equipment to restore a 211 E Class to full working order after a disconnect of the battery(s), the total level of expertise required is be able to walk in a straight line, read and push buttons.

No it will not put you in a tow situation, but that is not the issue here. What was said was - that it is not recommended and you WILL have problems resetting items - as the person concerned will just make more problems than leaving it connected.

As i said in my first post i agree that disconnecting the battery in this situation is overkill the car will be just fine as it is, if it ain't broke don't fix it right

I don't mean to be argumentative but what's with the "you WILL have problems" no you won't it's a completely pain free process and I've done this so many times I've lost count, disconnecting the battery provides a nice safety net in many situations as Malcolm pointed out so all these post's i see scaring people into not disconnecting a battery when working on a car (especially the electrical system) is counter-productive, dangerous and expensive when things go wrong.

I really don't mean to come across as a jackass thats not my intention at all i spend time on these forums to help people not argue but do you have any proof to backup what your saying? I have MB's factory training and MB's own WIS telling me when in doubt pull the plug.

 

[jaymanek]

by the way most of the airport car parks hold battery boosters so if it gets a bit low just attach one to the battery.. start the car and leave the booster attached for around 2 minutes... all should be well...

 

[DansSlk]

by the way most of the airport car parks hold battery boosters so if it gets a bit low just attach one to the battery.. start the car and leave the booster attached for around 2 minutes... all should be well...

Cool, never known about that before.

Thanks

 

[television]

Cool, never known about that before.

Thanks

I have also heard that some have MB equipment as well, Gatwick I think

 

[television]

On a technical point for those that understand them, these ECU's are connected by multi plugs containing up to 32 cables. Some ECU contain op amps and inverters, if you try and insert a multi plug when its live, how do you know what is on what pins and what if you do not make contact with them all at the same time. if an op amp is powered up with an out of balance power supply the output will swing hard over to the + or- that connects first, that millisecond is enough to do the damage, and there is no way back, as components have received a voltage that they should not have done.

I have said here many times that if you bought a new TV and hand soldered every joint the chances are that it would never go wrong.
95% of sets that come my way have had on dry joint, this can have the same effect as pulling out a live plug on a car. What happens is the arc on the joint in power circuit can triple the voltage/ signal or what ever is there, in a flash up to 20 components destroyed, this is easy for me to do, but in a SAM and ECU you cant get inside the things to repair them, and they all cost in the hundreds of pounds.

Take a simple seat controller, that has to supply several amps to move the seat, and that is big current, and when you have a bad connection it will fail in a big way.

Even with cars as with other electronics you have to ask yourself why did it go, in the first place, when you pull a plug out of a live circuit you will know why

 

[tromppost]

you could get one of those battery trickle chargers that plugs into the lighter socket and works of the sun. But only if the lighter sockets works with out the keys in!

 

[DieselE]

You don't need any form of diagnostic equipment to restore a 211 E Class to full working order after a disconnect of the battery(s), the total level of expertise required is be able to walk in a straight line, read and push buttons.



As i said in my first post i agree that disconnecting the battery in this situation is overkill the car will be just fine as it is, if it ain't broke don't fix it right

I don't mean to be argumentative but what's with the "you WILL have problems" no you won't it's a completely pain free process and I've done this so many times I've lost count, disconnecting the battery provides a nice safety net in many situations as Malcolm pointed out so all these post's i see scaring people into not disconnecting a battery when working on a car (especially the electrical system) is counter-productive, dangerous and expensive when things go wrong.

I really don't mean to come across as a jackass thats not my intention at all i spend time on these forums to help people not argue but do you have any proof to backup what your saying? I have MB's factory training and MB's own WIS telling me when in doubt pull the plug.

It is unfortunate that Malcolm introduced the issue of working on a car without disconnecting the battery and you seem to be following him down that path.

I completely agree that if anyone was planning to work on the electrics of their car then disconnecting the battery makes good sense. However, this thread is all about what precautions to take when leaving the car standing for two weeks or more.

Maybe "problems" is too strong a word for the issues that would arise after storing the car with the battery disconnected. The sort of things I was thinking of are:

Need to input security codes into COMAND or Audio system;
Automatic gearbox going back to factory settings and having to re-learn driving style;
Window auto closing having to be reset;
Parameter Steering settings lost (on E320 and above).

There are probably others. In other words, nothing that would prevent the car from starting and being driven but for several hours/days it would not feel the same car as the one that was parked up.

 

[television]

It is unfortunate that Malcolm introduced the issue of working on a car without disconnecting the battery and you seem to be following him down that path.
Rightly or wrongly, this did come into the thread, but as a back up to myths that are floating around

I completely agree that if anyone was planning to work on the electrics of their car then disconnecting the battery makes good sense. However, this thread is all about what precautions to take when leaving the car standing for two weeks or more.
Agreed

Maybe "problems" is too strong a word for the issues that would arise after storing the car with the battery disconnected. The sort of things I was thinking of are:

Need to input security codes into COMAND or Audio system;
Automatic gearbox going back to factory settings and having to re-learn driving style;
Window auto closing having to be reset;
Parameter Steering settings lost (on E320 and above).

Comand has never needed a code, most cars and this one should have come code once from new. If a code was needed , you have the number and it is entered in 15 sec max.
Driving style?? I will stick my neck out here and say that I do not think that Dan believes in this anymore than I do. Driving style?? what driving style, crawling around a town center or 70mph on the motorway. In the workshop manuals there are set figures that one works too as to the RPM and when the next gear change takes place. Nothing on driving style as the box memory is not even large enough to store all the fault codes that can arrise. This should be discussed elsewhere.
The windows you can do driving along or the next morning.
ESP lamp would probably be out by the time you left the car park

There are probably others. In other words, nothing that would prevent the car from starting and being driven but for several hours/days it would not feel the same car as the one that was parked up.

.

The only others are fairy tails. Would not feel the same ?? One normally gets feeling from a car from one day to the next, and not after not being away from it for two weeks.

Dan is the only person that I can have a sensible conversation with on these issues, his hands on experience is worth 10 times more than any other input here, and that includes me.

 

[DansSlk]

DieselE, i do agree and i will say again if you are leaving your car for 2 week's DO NOT disconnect the battery, it won't do you any favours so why bother the car will start fine, not only that but you will be without central locking and the alarm.

Just as an aside the following is all the needs to be reset after disconnecting a battery on the E class and it is all done using the button's in the car, no diag kit needed.

Reset steering angle sensor (turn wheel lock-to-lock) if applicable to the car's MY.
Reset pano roof.
Reset sunroof.
If no COMAND set time on cluster.

And thats it, no loss of any other settings.

 

[Dieselman]

And thats it, no loss of any other settings.

Windows.?

 

[DansSlk]

Nope not on the E mate