Woodshoe

Hello, is the location of the starter battery for the 2017 e400 some kind of CIA eyes only classified document? I've been trying to Google it for days. Forums and all. My auto start stop is intermittent and my car has "insufficient charge for standby mode".

Plutoe

you have sts out of most as the subject and body of your post are very different-----,but if the car isnt stolen I would go to the dealer for warranty work, but on the 213 the ECO battery was behind the left rear seat

ua549

The OP posted in the wrong forum. This is the W214 forum.

On the W213 there is a large capacitor at the top of the front passenger foot well with functions similar to the now replaced aux battery. It is difficult to access because the glove box and trim must be removed. The W214 location is most likely the same.

estark

My W214 has a 12V battery in the engine compartment right side and the 48V battery for the mild hybrid function in the trunk.

2012 merc amg

Generally eco start intermittently working is the starter battery under the hood. They are good for about 5 years. The aux battery is under the passenger dash behind the glovebox and it’s actually a capacitor box.

Woodshoe

Thank you that makes sense then why I'm seeing 14.8 v on the charging system most of the time. Maybe I'll upgrade to a antigravity lithium battery while I'm at it.

cruise2024

Does anyone know if a battery maintainer/trickle charger will charge the auxillary battery/capacitor (along with the main battery) when connected to the normal charging posts under the hood?

2012 merc amg

No it just charges the starter battery. MB does not recommend charging the Aux separate either.

ua549

There is no need (or way) to charge the capacitor. It will be automatically charged once the car is started.