Skip to main content

How it works

SEMS works in a continuous loop: it measures the site, forecasts the next hours, makes a plan, carries it out and corrects.

How SEMS works

Measuring​

The controller reads your inverters, batteries, meters and chargers over RS485 or the local network, about once a second. The meter at the grid connection matters most, because it shows exactly what flows in or out of the site.

Forecasting​

SEMS forecasts solar production from the weather and your own panels' past output, and consumption from your site's history. Both are corrected during the day. See Forecasting.

Planning​

SEMS plans in 15-minute steps, 24 hours ahead by default and up to 72, from the forecast, your buy and sell prices and the limits that apply. It aims for the best result of your chosen strategy over the whole period, not just the next few minutes.

Controlling​

SEMS sends charge and discharge commands, solar power limits and charging current to your devices, and corrects within seconds so the grid meter lands on the planned value.

Local first​

Everything above runs on the controller. The internet is used for weather, prices and optional remote support; if it drops, SEMS keeps measuring, controlling and recording. To learn what SEMS weighs when it chooses, read How SEMS decides.