Winter approaching - some timely advice!

[kwakdonut]

Hi all,

this really applies to anyone who has an MB with the main battery located in the boot!

This morning, with no warning at all, my car refused to start. Everything pointed towards a very dead battery. 'No problem' I think, 'I'll get the boot open and get my start/charger on it'.

Yeh right! Boot stubbornly refused to open. Inside switch, key fob, nothing.

Quick search on the forum showed up that quite a few of us have encountered a non-opening boot when the battery gives up (mostly CLK's oddly enough). It seems the 'cure' is copious amounts of WD-40 into the lock, confirmed via a quick phone call to Olly at PCS (thanks again, Olly!).

Boot open, RAC called and confirmed 10.0V at the battery. Got the car started and off to Euro Car Parts for a spanking new Bosch battery at £82!!

So, really, my advice is two-fold.

1) Get your batter(ies) checked and,
2) Lube your boot lock!

Thanks all
Tony

 

[GordonTarling]

Your car should have a set of terminals under the bonnet for jump-starting, mine has - didn't you try those?

 

[BlackC55]

He does not have them on his. NEVER jump a MB from another car. It is possible to do some expensive damage. Use a Jump pack only.

 

[finisterre]

surely a battery is a battery, if you connect another in parallel how can you do damage?

interested, not disbelieving.

 

[BlackC55]

They can be charged to over 15V. That will Kill a SAM unit DEAD. See it this week and last. Both blew the rear SAM. Jumped by the owners.

 

[kwakdonut]

The RAC guy who came out knew his stuff and was VERY careful! My battery was actually dead enough to need 10 minutes charge from his van and then the use of his jump-pack before it finally came to life!

New Bosch battery now fitted (£82) from ECP. 90Ah compared to the 70Ah it replaced. Also, I have finally found out why my car's battery mounting point had two different holes for the clamp - new battery somewhat larger but fits perfectly!

 

[BlackC55]

The MB batteries are very good value too. 85 for a proper one.

 

[kwakdonut]

I actually didn't phone MB Swindon for once and I have to drive pass them to get to ECP!!

I thought MB batteries were Bosch anyway? I stand corrected if not....

 

[BlackC55]

Bosch or Varta I think. They no longer have the label on them.

 

[GordonTarling]

Olly - I fully believe what you're saying but I'm struggling to understand how a 12V battery or system can get to 15V or more?

 

[sspeed]

If I remember correctly your cars alternator outputs 14.8 volts.. Well mine does anyway..
I have heard before on "The other side" that you have to be very carefull when jump starting a Merc..
I guess the older Mercs without the over complec electronics wont be a problem with jump starting.

 

[ringway]

They can be charged to over 15V. That will Kill a SAM unit DEAD. See it this week and last. Both blew the rear SAM. Jumped by the owners.

This may explain something...

I (and two very good auto electricians) have been trying to get my rear wiper working for the last 6, months without any luck. I have jumped my car a few times in the past...

I've even fitted a brand new switch..

Is it possible I've damaged the PSE unit Olly?

Alexanderpatient (definitely knows his stuff) did suggest on the forum that the rear wiper fault could lie in the PSE unit which adds plenty of weight to that theory as well.


I did actually worry about causing some damage (and explained this to young Ringway Les last week) but only if the ends of the jump leads touched whilst connected to the 210.

TIA,


Paul.

 

[Iain]

They can be charged to over 15V. That will Kill a SAM unit DEAD. See it this week and last. Both blew the rear SAM. Jumped by the owners.

Where is the rear SAM unit located on a late W202 Olly? This could be the problem with my non-opening boot (boot won't open thread).

 

[talleres]

Maybe get a battery conditioner too....

Investing in a battery conditioner would have probably meant you could keep your old battery and avoided the hassle of getting into your boot.

The Merc battery conditioner is a rebadged CTEK. It'd cost you about the same as the new battery you bought.

It would also avoid blown electronics such as the SAM Unit.

Hope this helps.

 

[kwakdonut]

Investing in a battery conditioner would have probably meant you could keep your old battery and avoided the hassle of getting into your boot.

The Merc battery conditioner is a rebadged CTEK. It'd cost you about the same as the new battery you bought.

It would also avoid blown electronics such as the SAM Unit.

Hope this helps.

A sound idea but unfortunately the car is kept in a garage with no available electricity!

The battery, AFAIK, is the original and I was going to get it checked before winter just in case. So really, an almost 8 year old battery hasn't done too badly.

Most of my driving is either long 60-80 mile motorway or 12 miles to work so the battery gets cycled and recharged fully.

My motorbike on the other hand has an Optimate fitted and has so far lasted 3 years which isn't bad for a motorbike battery!

 

[BlackC55]

Olly - I fully believe what you're saying but I'm struggling to understand how a 12V battery or system can get to 15V or more?

Alternators can charge at 18V+. I have see it when they are faulty. I had a Smart thet produced 18.4V from a brand new alternator. It made it do very starnge things.

A regular battery that has been sat on a shelf can have 15V in too.

Some Amperage outputs of old alternators can spike a high output every now and then. This will also do damage if you are jumping an MB from it.

This may explain something...

I (and two very good auto electricians) have been trying to get my rear wiper working for the last 6, months without any luck. I have jumped my car a few times in the past...

I've even fitted a brand new switch..

Is it possible I've damaged the PSE unit Olly?

Alexanderpatient (definitely knows his stuff) did suggest on the forum that the rear wiper fault could lie in the PSE unit which adds plenty of weight to that theory as well.


I did actually worry about causing some damage (and explained this to young Ringway Les last week) but only if the ends of the jump leads touched whilst connected to the 210.

TIA,


Paul.

Possibly. You need to check the wiring diagram to see where the signal comes from. I had a PSE on a 210 estate fill up with water about 3 weeks ago. His rear wiper was going mental!

Where is the rear SAM unit located on a late W202 Olly? This could be the problem with my non-opening boot (boot won't open thread).

It does not have a rear SAM. It has a PSE though. Have you broken the lock to gain entry?

 

[ringway]

Possibly. You need to check the wiring diagram to see where the signal comes from. I had a PSE on a 210 estate fill up with water about 3 weeks ago. His rear wiper was going mental!

Thanks Olly.

I'll try and get hold of a wiring diagram.

My PSE is a used one that worked fine when I first put it on the car.

My old unit was goosed by the water issue, but this won't happen again because I've cleaned out the drain below the wiper, thoroughly.

I think it may be the PSE, because the washers work and the motor to the wiper is getting power.

 

[Iain]

Alternators can charge at 18V+. I have see it when they are faulty. I had a Smart thet produced 18.4V from a brand new alternator. It made it do very starnge things.

A regular battery that has been sat on a shelf can have 15V in too.

Some Amperage outputs of old alternators can spike a high output every now and then. This will also do damage if you are jumping an MB from it.



Possibly. You need to check the wiring diagram to see where the signal comes from. I had a PSE on a 210 estate fill up with water about 3 weeks ago. His rear wiper was going mental!



It does not have a rear SAM. It has a PSE though. Have you broken the lock to gain entry?

Not broken lock yet Olly.

 

[Bellow]

Would you get away with jump starting a SAM equipped car if the vehicle being jumped from had its engine switched off?

 

[markjay]

Was wondering about that myself - I think he said that some off-the-shelf batteries has 15V?

Can an in-car battery with engine off have such high voltage?