Safety first: Turn off power to all interconnected chargers before modifying bus wiring.

Check topology: Verify that the Wallbox units are wired according to the load management diagram (daisy chain, correct polarity on A/B lines, proper termination resistors).
Verify roles: In the app or installer interface, confirm that one unit is configured as master and others as slaves, and that group IDs match.
Inspect bus wiring: With power off, check the integrity of the twisted pair used for RS‑485/CAN. Look for loose terminals, reversed polarity, or damaged cable.
Test without external meter: Temporarily disconnect the external power meter (if used) and configure the system for standalone operation. If Error 15 clears, the meter or its wiring is faulty.
Module replacement: If wiring and configuration are correct but communication still fails, replace the communication interface module or main board on the affected unit.

Load management faults can lead to overloading the supply if bypassed. Ensure the system is correctly repaired before enabling full‑power charging.

Wallbox indicates 'Error 15'; charging is disabled and may reference 'load management' or 'power sharing' issues.

Possible Causes