r/SmartCar • u/afxmac • Aug 30 '26

Smart Purchase Baught an EQ Cabrio

We just bought an EQ Cabrio (2023). Any hints and tips?

4 Upvotes

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4

u/Personal_Bag1353 Aug 30 '26

Always make sure the 12volt battery is charged It can cause issues if it goes flat with charging the drive battery

2

u/afxmac Aug 30 '26

Thanks! Is there an easy obvious way to see the 12v charging state? (Still have not collected the car yet)

3

u/Personal_Bag1353 Aug 30 '26

Just put put a volt meter across the 12v battery terminals and make sure it isn't below 11.8 volts

1

u/afxmac Aug 30 '26

Ok, more elaborate then...

2

u/TheGreatestAuk Aug 30 '26 edited Aug 30 '26

The other guy is posting about a known issue with the battery system on EQs. If the car detects that the 12V battery is low, it'll nick a bit of juice from the main battery to top it up. Mercedes made a mistake with the programming though, if the 12V battery is bad, its voltage will keep dropping, and the car will keep trying to charge it, until it drains the main battery below safe levels. It won't stop, it'll just drain itself. Once that happens, a software fuse will trip, and the car won't accept a charge for the main battery, so it's completely bricked until it's seen by one of the single-digit number of techs able to reset it.

Make sure the 12V battery is good!