Solar panels had been replaced after the originals were damaged. During reinstallation the MC4 connectors between the solar panels and the Victron MPPT were left disconnected — no power was reaching the MPPT input. The Victron Cerbo GX showed the MPPT relay in the open state. Additionally, a blown or degraded fuse in the solar cable circuit was later confirmed as a contributing factor. Remote diagnosis was achieved via VRM after enabling Remote Console on the Cerbo and connecting via mobile hotspot.

1. Open VictronConnect app and connect to the MPPT. Check Panel Voltage — if 0V, no power is reaching the MPPT from the panels. 2. Physically inspect the MC4 connectors between panels and MPPT. Each panel string has 2 connectors (positive and negative). They must be fully mated — male into female, click audible. 3. On the Cerbo GX, navigate to the MPPT device page and check relay status. If relay shows 'open', the MPPT is not receiving panel voltage. 4. If MC4s appear connected but voltage is still 0: check for a fuse or switch in the solar cable run between panels and MPPT. Inspect fuses for continuity. 5. After connecting MC4s correctly, verify MPPT BULK LED begins flashing and panel voltage appears in VictronConnect. 6. For remote troubleshooting: enable Remote Console on Cerbo (Menu > General > Remote Console), connect Cerbo to internet via mobile hotspot, access via VRM portal.