W204 battery charging question.

[mikrt]

Had my 2013 W204 nearly 2 weeks now and I haven't seen the eco go green once. I'm going to give the batteries a charge over the weekend, but if like to know does the small battery in the boot get charged at the same time as the engine bay one (via posts), or do I need to charge it direct ?
Thanks in advance.

 

[classiccarzone]

It is most likely because the primary battery is not fully charged. Have a look at this thread

ECO green light operation - Mercedes-Benz Forum

 

[mikrt]

Thanks for that classiccarzone. I guess I should charge the battery direct after disconnecting it, with all the scare stories of over voltage.

 

[classiccarzone]

....and while you are at it check the alternator output and check to see that the freewheeling pulley is operating ok

 

[190]

I guess I should charge the battery direct after disconnecting it, with all the scare stories of over voltage.

The owners manual should list the safe charging voltage. From memory it's as high as 14.7 or 14.8 volts so provided you don't use a completely unregulated charger there is no need for disconnection. These days all chargers are regulated in some fashion with only very old chargers being unregulated. If in doubt monitor the charging voltage with a digital meter if you have one.