C300h W205 Battery Location

[wongl]

I am trying to locate the 12V battery on my C330h diesel hybrid (non-plugin) to install my CTEK charger leads to the battery terminals. I cannot find the battery in the engine bay nor in the boot. Does anyone know where it is located? Thanks

 

[Gallon]

It should be in the engine bay, passenger side. It is under the large plastic cover which has the red sliding cover for the 12v power supply connection.

 

[wongl]

It should be in the engine bay, passenger side. It is under the large plastic cover which has the red sliding cover for the 12v power supply connection.

Interestingly when I lifted the trim surrounding the Jump Start point there battery isn't there!

 

[wongl]

I found the batter in the boot/trunk, and it looks like there is a massive heat-sink fitted to cool the 12V battery!

 

[wongl]

Here is the CTEK wiring attached to the battery in the boot/trunk. Also a photo with the trim refitted and the plug poking out.

 

[whitenemesis]

Does the 12v battery have a monitoring module? If so wouldn't one be advised to wire the CTEK across the module? Does it mention anything in you handbook?

 

[wongl]

Does the 12v battery have a monitoring module? If so wouldn't one be advised to wire the CTEK across the module? Does it mention anything in you handbook?

Hmm, that is an interesting point - there are a couple of modules attached to the battery which I cannot easily identify. I would have thought that it would be safer to hookup the CTEK directly to the battery rather than through a module since the charger will be charging the battery while the alternator is not active?

 

[whitenemesis]

I only mention it as on my 219 the handbook stipulated connection across monitor module, which is what MB did for me. Apparently the system needs to know the battery is being charged.
What does your handbook say?

 

[wongl]

Thanks for the warning whitenemesis as having checked the CTEK video, I decided to fit the negative to the chassis rather than directly to the negative terminals of the car as recommended in the CTEK video.

 

[wongl]

I only mention it as on my 219 the handbook stipulated connection across monitor module, which is what MB did for me. Apparently the system needs to know the battery is being charged.
What does your handbook say?

Handbook on the C300h (which is now online doesn't mention anything expect to charge via the Jump start terminals. Any chance of a photo of your battery wiring as done by MB?

 

[whitenemesis]

Handbook on the C300h (which is now online doesn't mention anything expect to charge via the Jump start terminals. Any chance of a photo of your battery wiring as done by MB?

Unfortunately, no pictures.

 

[Gallon]

Is that a Lithium Ion starter battery,
which would explain the heat sink & the fact the battery is in the boot rather than in the engine compartment.

 

[Gallon]

Hi, forget my previous post, it's not applicable to your car.

 

[Trik]

Here is the CTEK wiring attached to the battery in the boot/trunk. Also a photo with the trim refitted and the plug poking out.

Hi sorry to tell you this but you have connected your ctek charger to hybrid battery ! PLEASE DONT TRY CHARGE YOUR HYBRID BATTERY IT WILL DAMAGE IT ! You need To connect the fixed terminals to the starter battery.
You also don’t need to hook up a hybrid as the car will always maintain enough power to fire the car up.

 

[wongl]

Hi sorry to tell you this but you have connected your ctek charger to hybrid battery ! PLEASE DONT TRY CHARGE YOUR HYBRID BATTERY IT WILL DAMAGE IT ! You need To connect the fixed terminals to the starter battery.
You also don’t need to hook up a hybrid as the car will always maintain enough power to fire the car up.

Hi Trik,

Welcome to the forum.

No, I checked that I have connected the CTEK charger to the 12V Varta battery in the boot. The hybrid battery is a high voltage battery and not a 12V battery.

 

[Trik]

I think you need to check that with Mercedes , I also have a hybrid and have been told under no circumstances connect any charging equipment to the battery in the boot as that is the hybrid battery and not a standard 12v battery.

 

[RichardOakley]

Interestingly when I lifted the trim surroundingView attachment 82187 the Jump Start point there battery isn't there!

This is the same as mine, i think the battery in the boot must be the 12v. But if that's the case where is the hybrid battery?

 

[Deleted member 113659]

This is the same as mine, i think the battery in the boot must be the 12v. But if that's the case where is the hybrid battery?

I think it’s in the front passenger footwell?

 

[Diesel Benz]

I think it’s in the front passenger footwell?

I think you are thinking about the small support battery that does not exist in the "h" hybrid.

 

[Diesel Benz]

This is the same as mine, i think the battery in the boot must be the 12v. But if that's the case where is the hybrid battery?

Seen this:

New C300h Hybrid Owner - no start/stop or electric even on Eco? | General Discussion

johnboy99 Glad to read it was sorted. Mine continues to be fine. Debden sorted it more by luck than judgement for me though I think as they do not seem aware of it as a known issue unlike other dealers...

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