As soon as the state of charge of the 12-volt battery has fallen below a certain threshold, it is recharged from the high-voltage battery via the DC/DC converter. This ensures a sufficient state of charge of the 12V battery.
The recharging function is active in the following situations:
- During the journey.
- During the charging process: The 12-volt battery is charged in addition to the high-voltage battery.
- During the stationary phases, the state of charge of the 12-volt battery is checked every 2 days and recharged if necessary. Noise from the fan and coolant pump may be audible during recharging.
Note:
If the 12-volt battery had to be recharged three times in succession during a longer standstill phase, the following message appears when the CE 04 is switched on: "Vehicle battery condition. No restrictions. Have it checked by a specialist workshop".
Background: If the state of charge of the high-voltage battery falls below a critical threshold, the 12-volt battery cannot be recharged. To ensure that the recharging function can always be activated when required, a sufficient state of charge of the high-voltage battery must be ensured.