Citroen Jumpy Battery Discharge

Sounds like a charging issue. Have you checked the voltage across the battery terminals while the engine is running? It should be around 14V. If it's lower, the alternator might not be charging correctly. Also, has the battery been load tested? A failing battery can cause similar symptoms even if the charging system is working.

I haven't done a load test. Is there a way to test if the battery sensor is defective before replacing the alternator or battery? I want to avoid unnecessary costs.

You can use a multimeter to check the sensor's output voltage, but interpreting the readings requires specialized knowledge and tools. A defective battery sensor is likely, and it often causes incorrect charging. A proper diagnostic check at a workshop is best to confirm this before replacing parts. They can pinpoint the fault. Replacing the sensor is the most economic first step.

Thanks for the advice. The workshop confirmed the battery sensor was defective. The repair cost 315€, including the sensor replacement and labor. Everything is working now.