Fluence electric undervoltage error

Hey there! Electrical issues can be tricky. Undervoltage points towards power supply problems, definitely. Before diving into a new battery, have you checked the battery terminals for corrosion or loose connections? Also, a voltage drop test might be useful to see where the voltage is being lost. Could also be a bad voltage regulator, preventing the battery from charging properly. Does the alternator seem to be working correctly?

Thanks for the tips! Where exactly should I be testing for the voltage drop? And how would I check if the voltage regulator is working properly with a multimeter? I'm not sure what the values should be.

Alright, to test for a voltage drop, put your multimeter leads on either end of a cable, like the positive or negative battery cables while the car is trying to start. A significant reading (more than 0.5V) indicates resistance and a drop. As for the voltage regulator, it's tricky without proper equipment. You'd typically monitor the battery voltage while the engine is running. It should be around 14V. Honestly, with electrical gremlins, especially on an EV, sometimes it's best to let a workshop diagnose it properly before you start swapping parts. You don't want to fry anything!

Thanks for the advice, I took it to a shop. Turns out it was a dead cell in the main battery, as suspected. New battery fitted, cost 290€, and everything is back to normal.