I have no permanent solar but I’ve had an AC300 with one B300 for several years. I live in an area with frequent power failures, and I’m often away from home for periods of weeks or months. To keep the food in my freezer safe for longer during power failures while I’m away I connect the freezer to the AC300. Of course it uses 35W day and night while I’m away, which diminishes the running time of my single B300 battery.
I’ve just gotten a second AC300 and a B300K so that I could operate them in the split-phase mode to be able to run my 240V well pump using portable solar panels in the event of a power failure lasting days or weeks. I have the split-phase charging cable, and while I’m at home, after power failures I plan to recharge the two batteries from my 50A 14-50R garage receptacle using the split-phase cable with a 14-50P-to-L14-30R adapter.
I’ve been thinking about how I’ll use my system to extend my freezer’s life during my periods away from home. I could leave the split-phase system as it is, but I’d only be using one leg and I’d only have one battery for my freezer to use. What I’d like to do is to disconnect one 120V leg of the charging cable from its AC300 and then connect its battery as a second battery on the other AC300, doubling the battery capacity and only burning 35W on one AC300.
Is there anything wrong with this plan? Can I leave the split-phase setup intact with the fusion box’s input cables and communication cable connected and have one AC300 powered off, drawing power from only one leg of the split-phase charging cable?