12v battery

[kevh9]

Hi I have a c220 w205, every now and again I get a message saying " start engine see instruction manual". The car starts ok without any struggle and fires up every time. Last time it did this i bought a new battery, about 4 years ago. Mercedes Benz said both batteries are fine and it`s charging ok.Any ideas why this happens please.

 

[daveenty]

Does the car get used regularly? They don't like being left unattended and will often sent the message you are seeing. You have a few levels to come with these messages by the way, mine is "Critical" quite often.

A lot of people leave their cars on trickle chargers if they're not being used often to maintain a constant charge level.

 

[Srdl]

Is this when you’re sitting in the car with the engine off? I have had it in the past when I have the radio or music on and the engine off. The Audio 20/Comand system uses quite a lot of juice.

 

[kevh9]

Does the car get used regularly? They don't like being left unattended and will often sent the message you are seeing. You have a few levels to come with these messages by the way, mine is "Critical" quite often.

A lot of people leave their cars on trickle chargers if they're not being used often to maintain a constant charge level.

No not a lot of use. After thought mime says Critical as well. I will try trickle charging it.

Thanks for advice.

 

[kevh9]

Is this when you’re sitting in the car with the engine off? I have had it in the past when I have the radio or music on and the engine off. The Audio 20/Comand system uses quite a lot of juice.

Once or twice but mainly after its been stood a few days.

 

[rich.g.williams]

Worth having a look at this recent thread:-

Parasitic Battery Drain

Its possible to discover what is drawing current from your battery, surprisingly even quite low levels of "parasitic drain" can flatten a big battery in days.

The problem is if the battery spends a lot of its life partially charged it will deteriorate faster. The magic number is 12.4 Volts - if a Lead Acid battery sits at less than 12.4 Volts for days it will be damaged.