Charge a Dead battery help

[hod05]

Hello

I have an E class 250 CDI that I've had sitting idle since the lockdown began and now I'd like to get back on the road.

Unfortunately the battery has gone dead. Still power to the radio and dials just not enough to start the engine.

I have a charger device but I'm unsure I can use it. If it is suitable (see pic) I'm concerned about doing this incorrectly and damaging the electrical system.

Reading the merc instructions book it says a jump start can be done by connecting the positive terminals of both batteries together and the negative to the earth point in the engine bay.

3 questions

1. Is this the same case if using a charging device? Positive to positive negative to earth?

2. Where is the earth point? The manual diagram isn't very good they could have done to provide a better drawing.

3.is the pictured charging device suitable? Do you need to buy a specific merc one or some kind of merc approved one?

Thanks. Sorry if it'd a daft question but I've heard some horror stories about jumping these incorrectly.

Cheers

Edit
Is this the earth point with the brown wires?

 

[Tony Dyson]

In answer to your questions;

1, Yes
2, Earth point 5 in your manual is a brass coloured pillar mounted to inner wing adjacent to your FOS shock absorber
3, Your battery charger is a basic charger and fit for purpose, turn everything off in your car, connect the charger and turn it on, the indicators should indicate when charging is complete.

 

[hod05]

In answer to your questions;

1, Yes
2, Earth point 5 in your manual is a brass coloured pillar mounted to inner wing adjacent to your FOS shock absorber
3, Your battery charger is a basic charger and fit for purpose, turn everything off in your car, connect the charger and turn it on, the indicators should indicate when charging is complete.

OK thanks a couple more questions, do I need the key in the ignition or not. If the key is not in the vehicle everything will be switched off?

Is this the earth point? I can't find anything brass inside the engine bay

Thanks again.

 

[Tony Dyson]

No key needed
Yes, + to 2 under red slider 1 and the earth point should be as indicated at position 5

Any sound metallic connection to the chassis will do and if you can purchase a good connection to the brown wires lugs this will be enough to carry the charging currents.

 

[hod05]

No key needed
Yes, + to 2 under red slider 1 and the earth point should be as indicated at position 5

Any sound metallic connection to the chassis will do and if you can purchase a good connection to the brown wires lugs this will be enough to carry the charging currents.

OK thanks alot couldn't quite get purchase on the brown lugs but got a good connection on the bolt that secures them so hopefully it'll be OK

Thanks

 

[grahamcol]

Just a word of caution. Not only is the ignition key not needed, it’s a positive no no to have the key in the ignition whilst charging.

 

[Donald McPherson]

Just about every car built in the last 10 plus years will have something still on even with the key off and removed.
Personally I prefer to remove the terminals when charging.

 

[EmilysDad]

.....
Personally I prefer to remove the terminals when charging.

but not every car has an easily accessible battery .... mine is under my seat & not that easy to get to, but there are nice easily accessible charging/jump start points under the bonnet

 

[range rover]

Just about every car built in the last 10 plus years will have something still on even with the key off and removed.
Personally I prefer to remove the terminals when charging.

Couldn't agree more, that way you are sure nothing is going to get fried.

 

[Submariner1]

Couldn't agree more, that way you are sure nothing is going to get fried.

I was told to switch off all consumables, such as auto lights, air con, Comand, and remove Keyless Go plug. and not to use negative on Battery, but use the Earth Stub! To ensure I did not circumvent the Battery Control Module!