I have an installation with a Multiplus 48/5000/70-100 and 4x100Ah VRLA AGM batteries, operating mostly in island mode. There is some solar, there is also a permanent AC connection, limited to 16A.
This is a workshop and I have the Multiplus configured to operate in island mode whenever possible, and conditionally switch to AC input: when load is high and when battery voltage is low. It's a workaround for a deficiency of the Multiplus: I'd love to self-consume whatever I can from solar and *then* use as much AC as I need to supplement that, but Multiplus can't do that. So I have it set to auto-switch to island when batteries are charged and switch back to AC when they are low.
I use PowerAssist (it's the main reason why I bought the Multiplus!), because I really can't exceed the 16A on my AC connection: if I do, I trip a breaker that I do not have access to. Very annoying.
This installation has worked fine for a year or so. But I installed a larger machine recently, with a 3kW motor. The machine is on a circuit with a C16 breaker, which should really be C20 (rated max current at startup is 19A).
When I start the machine, if conditional AC input is enabled, lights dim, voltage in the installation drops to 140V, and the inverter shuts down after a second or so. I would have expected the inverter to immediately switch to AC and enable PowerAssist (if needed) instead.
If I disable conditional AC input and run the inverter from AC, I get an "overload" warning every time I start the motor, but otherwise things run fine.
Any advice is appreciated: I'd like to keep operating in island mode as much as possible and have conditional AC input enabled, without the inverter shutting down when I want to start the 3kW motor.