W220 Battery Discharging for fun

[chauffeurexec]

I have an ongoing problem starting problem with my S320CDI

Intermittently the car completely discharges the battery and will not start. Often even boost charging requires connection to the slave vehicle for 10 mins before it will even crank.

After starting a variety of malfunctions are displayed, usually that the Steering wheel is in the park position and the car should not be driven, even though it is not.

Have had the vehicle with 2 "specialists" who have reset the faults and said they could find nothing wrong. After the latest occurance they were adament that the wrong battery was fitted and fitted a "Gel" type battery costing £150. After 24 hours the car is completely dead again.

Anyone experienced anything similar?

 

[recycled]

alternator?

 

[Benzowner]

Alternator +1

 

[television]

So simple to test, if the car is running on 13.8 volt there is nothing wrong with the alternator

 

[chauffeurexec]

No indication of an Alternator problem, but worth checking I guess.

 

[lexuscol]

Sounds like something has gone short circuit and is drawing off amps, need to check all equipment for excessive voltage/amps draw. I think you may need the help of a specialist auto electrician.

 

[BTB 500]

Sounds like something has gone short circuit and is drawing off amps, need to check all equipment for excessive voltage/amps draw. I think you may need the help of a specialist auto electrician.

What capacity is the battery ... 75Ah? If so, to totally discharge in 24 hrs (as mentioned) you'd be looking for a drain of over 3 amps ... almost 40 watts. It's possible, but I'd also be looking at the charging system first.

 

[chauffeurexec]

Battery is 100ah, and went flat after being parked for 8 hours, thats a serious draw!

 

[Diesel Benz]

There is a good chance that one of the control boxes would not enter sleep mode properly. Should be able to find guides to perform quiescent current tests and allowed current values.

Easy to test for high currents (from malfunction) with a DC clampmeter. Then if high current is detected, either read fault codes or try disconnecting fuses for each control unit until the current draw disappears.

This would be difficult in the case that the current draw occurs randomly.

 

[BTB 500]

Battery is 100ah, and went flat after being parked for 8 hours, thats a serious draw!

Yup that's 12.5 amps, 150 watts! Like having the headlights on. Too much to be a control box or any other electronics, surely.

 

[television]

Yup that's 12.5 amps, 150 watts! Like having the headlights on. Too much to be a control box or any other electronics, surely.

I agree here completely, and there is nothing that could draw that without smoke.
This could be a battery with a high resistance cell, they do act like that when this happens.

 

[franey]

I have got exactly the same problem, facelift W220 320 cdi, overnight discharge. Very annoying, currently at auto electrician. Will let you know what happens. Did you get yours sorted???
Bren

 

[television]

This time of the year draws out the duff cell batteries, if your car was fine the day before, 99% of the time it is a high resistance cell, that is one cell loses its contact with the others when not under charge.

If the battery is 4 years old or more, then change it once this starts to happen. Many new batteries can go like it after 2-3 weeks and these are the cheaper in house brands

 

[l5foye]

Have any of the cars with battery problems got the factory phone system?
A friend's car was having similar battery problems which after quite a while were traced to a wiring problem with the phone.

 

[television]

Have any of the cars with battery problems got the factory phone system?
A friend's car was having similar battery problems which after quite a while were traced to a wiring problem with the phone.

I do not think that this will be the case with MB, and I have not seen anything of this nature recorded, possibly on a different make of car.

Most phone systems only draw milli amps

 

[glojo]

I Have had the vehicle with 2 "specialists" who have reset the faults and said they could find nothing wrong. After the latest occurance they were adament that the wrong battery was fitted and fitted a "Gel" type battery costing £150. After 24 hours the car is completely dead again.

I dislike this use of the word 'specialist' and would like to think a competent electrician would quickly locate such a significant discharge? I am not necessarily saying take it to a main dealer, but I am saying take it to someone that knows what they are doing.

Our 211 had a 0.6amp discharge which was also intermittent, but the garage still managed to locate it.

I'm not familiar with the numerous service bulletins that have been issued for the S-class but it appears this is an issue with a number of vehicles. When was the last time you had the car serviced at a Mercedes-Benz main dealer? I ask this only because they will apply all the latest service upgrades.

John

 

[television]

I dislike this use of the word 'specialist' and would like to think a competent electrician would quickly locate such a significant discharge? I am not necessarily saying take it to a main dealer, but I am saying take it to someone that knows what they are doing.

Our 211 had a 0.6amp discharge which was also intermittent, but the garage still managed to locate it.

I'm not familiar with the numerous service bulletins that have been issued for the S-class but it appears this is an issue with a number of vehicles. When was the last time you had the car serviced at a Mercedes-Benz main dealer? I ask this only because they will apply all the latest service upgrades.

John

As you say john, should be easy to find, the trick is not to break the path of the leak if there is one when you are joining up.

By using a meter with 3 leads its simple, you clamp the single lead onto the battery cable.

Next place the probe into the center onto the battery post, and slide the clamp up the probe, take the other lead with the clamp and clamp to battery post.

And thats it circuit not broken and any leak can be read off

 

[television]

This is the way the meter is joined up for the post above.

The can be a little confusing now as another poster has joined the thread, with the same symptoms but not the same fault.

My post above is how to join a meter up without loosing the path of the short.
If the battery does come completely disconnected in the process of joining up,then the leak can stop and you will be measuring no fault.

Do remember that AGM (glass mat) batteries cannot be charged on a automatic charger, they need charging at 10% of the capacity max.

 

[franey]

Nearly sorted.

Well well well !!
Car back from auto electricians. If the car was not used and the battery in full state then the battery would remain 'full'.
If the battery was 'full' and then driven, the battery would discharge. The alternator has been diagnosed as the problem!!
If you suffer similar symptons then you may like to try the 'test' by not using the car when battery is fully charged. Next morning the car should start but then quickly drain the battery. Alternator on mine being repaired tomorrow (a new one is £520 from MB) but from experience, it is as easy to replace the regulator unit or take it to a specialist to have reconditioned.
The alternator is a real dog to get to. Removal involves removing extended oil sump and turbo pipes.
While you are at it check the turbo impeller. Sadly mine has a few chips out of it so something has hit it at some point so will replace turbo at same time.
Will let you know the outcome of new alternator.

 

[franey]

PPS !!
Anyone got a turbo for S class cdi??