Solar panels

Solar power is your cheapest energy, but on sunny middays the market price can drop to zero or below, and exporting may cost you money. SEMS sends your solar where it is worth the most.

Export only when it pays

Surplus solar is exported only when the price after fees pays. Otherwise SEMS stores it in the battery, and if the battery is full and the inverters accept a limit, turns them down just enough until the price recovers. The same control keeps export within your contracted export power and any time block limit.

Without controllable inverters, SEMS still moves as much surplus as it can into the battery, but some export may remain. The Supported devices list shows which inverters SEMS can control.

Larger plants

SEMS limits whole plants through Huawei SmartLogger and SMA Sunny WebBox plant controllers, and shares a limit across several directly controlled inverters.

Arc-fault alarms

SEMS reads the arc-fault detector (AFCI) on inverters that report it, including SOFAR, ZCS, Growatt, Huawei, Solis and Sungrow models. An arc fault or failed self-test shows on the Events page as an error; SEMS never changes the inverter's protection settings.

Finding weak strings

On the Solar Layout page SEMS compares each inverter input with its neighbours over the last three days and shows the ones falling behind, often the first sign of shading, soiling or a fault.