I have a large boat that is powered by two seperate 120v 30a (North America) power feeds from shore. All devices onboard are 120v, distributed between the A-side and B-side of the panel, with no 240v equipment. I have two Multiplus-II 48/5000 inverters in split phase (switch as a group setting disabled) connected to a ~20kWh LifePO4 battery bank. Everything works great except one annoyance. They need to be setup in split phase mode in order to be connected to the same battery and have the Cerbo GX manage/control them as a group, but my marina's less-than-optimal wiring causes the GFCI circuit breakers to randomly trip during electrical storms or heavy rain. My setup continues fine if the B-side breaker trips, and the master multiplus will continue to charge the battery by itself while the slave unit will be inverting. If the power is lost to the master Multiplus, both multiplus units go to inverting mode and will run the battery down to nothing even though the second multiplus is recieving good power. In addition, even the AC OUT 2 of the slave will not output power, even though AC IN is powered....if the master unit is not getting AC power into it.
Even though it does not seem to be any technical reason why the inverters cannot behave independantly, there appears to be no way to configure them to keep the system alive if either one of the two units is being fed with power. The master unit is still there and online (inverting), so why can it not tell the slave unit to charge, enable AC OUT 2, and keep the batteries from going flat? I was excited when Victron seemed to be starting to address this type of issue with their 2x120v output models, but this setup will not work for me because the GFCI breakers at my marina are seperate 120v breakers and would instantly trip (because it is not configured as a 30a 240v circuit. In addition, they only offer this model in a 3000w model and I would need to parallel 3 of them to get the wattage I need...which does not seem ideal.
Any thoughts on why the second multiplus cannot be powered up if the first one does not have power? Both sides of my split phase setup run completely independant of one another, but is there any other way to configure my two units so either one getting power would keep my batteries charged? Any help would be greatly appreciated and would save me random 3-hour round trips in the middle of the night to flip the breaker back on. Thanks!
