C350e Auxiliary Battery location

[JoeD007]

Hi I have 2016 c350e that has just shown the message auxiliary battery malfunction. It came on the following day but today it hasn't appeared? As this is the hybrid version does it have an actual battery or is it a voltage converter? Mercedes garage want to charge £140 to diagnosis. Any help would be great please

 

[DubMerc]

Hi JoeD,

Haven't encountered this issue myself. Did you end up getting this sorted in the end?

 

[Deleted member 126969]

I’m sure I answered this very question already....

The C350e has 3 batteries. The HV one, a pretty chunky AGM 12V starter and services battery lurking under the boot floor and an auxiliary12V Lithium battery in the cabin, passenger side.

The 12V batteries are charged from the HV battery via a DC-DC converter, but I’ve no clue as to the charging strategy it uses. I wouldn’t be surprised if a long period of inactivity, with a low state of HV charge could lead to issues with the 12V batteries.

 

[DubMerc]

I’m sure I answered this very question already....

The C350e has 3 batteries. The HV one, a pretty chunky AGM 12V starter and services battery lurking under the boot floor and an auxiliary12V Lithium battery in the cabin, passenger side.

The 12V batteries are charged from the HV battery via a DC-DC converter, but I’ve no clue as to the charging strategy it uses. I wouldn’t be surprised if a long period of inactivity, with a low state of HV charge could lead to issues with the 12V batteries.

You did Chris in another thread. My question (and probably should have been made in that other thread) was whether the OP got the issue resolved and what was the outcome, so that we can add to the collective knowledge here.

 

[Deleted member 126969]

Ah, good! That I thought I’d answered it wasn’t proof I had! Memory ain’t what it was