I have a Cerbo/Multiplus 12/3000 based system on my boat. We live aboard full time and it has been flawless for 2 years. We have made no changes to our electrical system since installation. A couple of days ago I started to get a multiple strange symptoms, I hope someone can help trouble shoot.
Normally I would not think the two symptoms are connected, but they both showed up on the same day after 2 years of flawless performance, so it seems a big coincidence to be unrelated.
Symptom 1) The Multiplus has been switching modes spontaneously. Typically we control inverter with Cerbo control panel, and at night turn to "Off" and during day, turn to "On". Twice yesterday it switched modes. For example, yesterday under low load (watching TV) it switched to "Charger Only" and we lost AC power. But earlier in the day while under high load (induction cooking) it switched to "Inverter Only". I happened to be nearby and noticed shortly after it changed, but we didn't even lose AC power. Nothing logged on the Cerbo "Notifications" page.
Symptom 2) The same day the Multiplus problem started our main breaker (RCBO) has been occasionally trips (disconnecting) when I turn on our hot water heater. We had been doing some high loads (AC watermaker, hot water heater, laundry) and I thought it was perhaps just an overload situation, though in the past the Multiplus complains about overload before the RCBO trips. However after a thorough cool down period I turned on the water heater and the RCBO instantly tripped. Later I tried again, and it did not trip, and was able to make hot water. A third attempt, and it instantly tripped. It also tripped once with Laundry, so I don't think it is isolated to the Hot Water circuit. It has not tripped with any other cicuits, and we were able to do high load cooking without tripping the RCBO.
I'm not really sure where to even get started with trouble shooting. Suggestions welcome!
