EV charging

An electric car is often the largest load on a site, and usually it doesn't matter whether it charges now or in two hours. SEMS uses that flexibility to charge it from spare solar power.

Two ways to charge

On the EV Charger page you choose the Charging policy for each charger.

With PV surplus, the charging current follows the solar power your site isn't using, between the minimum and maximum you set, on one or three phases. You can keep a reserve margin against import, or allow some grid import so charging continues on a cloudy day. This mode needs the grid meter; if its reading is lost, the charger is set to zero.

With Maximum configured power, the charger runs at the highest power you allowed, for when the car must be full soon.

Turn on Enable strategy control to hand the charger to SEMS; it follows the strategy while automatic control is on for that system on the Strategy page. Switched off, the charger returns to its own settings.

Which chargers

SEMS is the local OCPP server for OCPP 1.6 JSON and OCPP 2.1 chargers. You register a charger on the EV Charger page and enter the address and one-time generated password SEMS shows you; the connection is encrypted. The SOFAR EV Charger connects over Modbus. See Supported devices.

You can also start and stop a session, set a current or power limit, mark the charger operative or inoperative, or unlock a connector by hand.

Sessions and costs

Every session is kept with its start and end, connector, energy, duration and stop reason. Filter by period and status, see totals with an estimated cost at a rate you choose, and export the list as CSV, for example for company cars or tenants.

You can describe up to four vehicles per charger, with battery size, daily distance and consumption, and SEMS estimates how much energy each needs per day.

Alarms

SEMS raises an event when a charger goes offline, a connector reports a fault, metering goes stale or a command is rejected, shown on the Events page with a link to the charger.