Battery light on my E220

[Peter Rushby]

On start up my battery light comes on and says check owners manual
If the car has not been Used for a few days
68 plate and is garaged

 

[Blobcat]

Hello and welcome

Have you measured the battery voltage?

Quite a few batteries have failed with less usage due to lockdown.

Much less than 12.6 V at rest with engine off can cause multiple errors

 

[Peter Rushby]

Hello and welcome

Have you measured the battery voltage?

Quite a few batteries have failed with less usage due to lockdown.

Much less than 12.6 V at rest with engine off can cause multiple errors

Its a brand new battery and the Mercedes garage have tested it on the computer and say then cant find a problem ? But on one occassion after a week in the garage it wouldnt start

 

[Peter Rushby]

Battery light prob

 

[Blobcat]

Sounds like you have a parasitic drain then... It can take awhile to work out which module isn’t switching off or switching back in again

If you can fit a battery conditioner then do so as that will keep your battery up to voltage.

 

[Peter Rushby]

Its a brand new battery and the Mercedes garage have tested it on the computer and say then cant find a problem ? But on one occassion after a week in the garage it wouldnt start

Sounds like you have a parasitic drain then... It can take awhile to work out which module isn’t switching off or switching back in again

If you can fit a battery conditioner then do so as that will keep your battery up to voltage.

Thanks for you help i Will check with Mercedes

 

[mioba]

Just out of interest how many is a few days.

 

[Peter Rushby]

It can take sometimes 3-4 days of no activity in the car

 

[Peter Rushby]

Just out of interest how many is a few days.

it can take 3-4 days of no activity in the car

 

[sonic]

Welcome, get a battery optimiser I believe they are about £15 in Aldi at the moment.
Leave it connected overnight, see if the error code appears on start up. If not you have a drain somwhere.

 

[mioba]

the fact there is an error after a few days shows a drain. A battery should be good for at least a couple of weeks Is standing at cranking.

As Blobcat says. Have you tested the V

Had this issue only been since you replaced the battery.

 

[A.J.]

Hi Peter, welcome to the forum

 

[Peter Rushby]

Welcome, get a battery optimiser I believe they are about £15 in Aldi at the moment.
Leave it connected overnight, see if the error code appears on start up. If not you have a drain somwhere.

What does the optimiser do ? Would the error code be from the optimiser ?

Welcome, get a battery optimiser I believe they are about £15 in Aldi at the moment.
Leave it connected overnight, see if the error code appears on start up. If not you have a drain somwhere.

Will I need to connect the optimiser to the battery and if so , do I need to make sure I connect it without doing anything else

the fact there is an error after a few days shows a drain. A battery should be good for at least a couple of weeks Is standing at cranking.

As Blobcat says. Have you tested the V

Had this issue only been since you replaced the battery.

The light started to come on 7-8 months ago after it was not used for a few days . I took it intro Mercedes at least 6 times to check and i suggested then replace the battery . Which then Saïd They did.
It then came on again after several days of no activity
And has been coming on after being stond for 2-3 days .
Mercedes claim they cant find the fault

 

[LostKiwi]

We have a similar issue with our 230.
If left overnight the auxiliary battery takes consumers offline. We found that turning off Comand then allowing the battery to go flat then recharging it the battery would hold for over a week unless Comand was turned on again.
A little more investigation has pinpointed it further to be the CD multi hanger.

These things really are only solved yourself by trial and error and patience.

Rather than take it to MB (who in my experience are pretty hopeless unless "Star says..." take to an auto electrician who will have the knowledge and skills to trace this type of issue.

 

[sonic]

What does the optimiser do ? Would the error code be from the optimiser ?

Will I need to connect the optimiser to the battery and if so , do I need to make sure I connect it without doing anything else


The light started to come on 7-8 months ago after it was not used for a few days . I took it intro Mercedes at least 6 times to check and i suggested then replace the battery . Which then Saïd They did.
It then came on again after several days of no activity
And has been coming on after being stond for 2-3 days .
Mercedes claim they cant find the fault

The optimiser is a very intelligent battery charger, apart from charging it conditions the battery as well. Once the battery is fully charged it switches off but monitors the battery state. When the charge in the battery starts to drop it starts charging again.
You connect it to the battery leave everything else turned off.
On my E class I can leave the bonnet up with the car locked & alarm set in the garage.
For £15 its worth having anyway, & it may solve your problem. As LK says MB are pretty crap at solving electrical faults, you need an auto electrician.
But try the optimiser first, if this solves the problem & you have a new battery it must be a current drain somewhere.
The battery on my E class is 9.5 years old, my wife's SLK battery lasted over 9 years. Optimisers really do work & prolong the life of a battery.

 

[grahamcol]

As above from Sonic. The battery in my now departed C280 was 12 years old when l p/xd the car earlier this year and I'm sure the CTEK charger/conditioner helped it to last this long. Of course, a good quality battery helps as well, mine being a Bosch.

 

[Peter Rushby]

Guys apart from the battery light , now just started when in the car with engine running my passenger got out and shut the door , the heated seats and the heated head rest came on full , Whats that all about

As above from Sonic. The battery in my now departed C280 was 12 years old when l p/xd the car earlier this year and I'm sure the CTEK charger/conditioner helped it to last this long. Of course, a good quality battery helps as well, mine being a Bosch.

See my new problem I’m sure these are all linked

 

[LostKiwi]

Various unrelated circuits interacting is almost always either a bad (wet?) SAM or bad earths.
They would be my first ports of call.

 

[Peter Rushby]

Various unrelated circuits interacting is almost always either a bad (wet?) SAM or bad earths.
They would be my first ports of call.

SAM?

 

[LostKiwi]

SAM?

Signals and Acquisition Module.
It controls many functions of the vehicle and in most cases there are two - one for the front of the car and one for the rear.
They are generally part of the fusebox and contain control electronics, fuses and relays.