Add chargeable battery charger

charger/battery.go

@@ -0,0 +1,109 @@
+package charger
+
+import (
+	"fmt"
+
+	"github.com/evcc-io/evcc/api"
+	"github.com/evcc-io/evcc/util"
+	"github.com/evcc-io/evcc/util/config"
+)
+
+type ChargeableBattery interface {
+	api.Meter
+	api.Battery
+	api.BatteryController
+}
+
+// Battery implements an api.Charger for controllable batteries
+type Battery struct {
+	*embed
+	ChargeableBattery
+	mode api.BatteryMode
+}
+
+func init() {
+	registry.Add("battery", NewBatteryFromConfig)
+}
+
+func NewBatteryFromConfig(other map[string]interface{}) (api.Charger, error) {
+	cc := struct {
+		embed   `mapstructure:",squash"`
+		Battery string
+	}{
+		embed: embed{
+			Icon_:     "battery",
+			Features_: []api.Feature{api.IntegratedDevice},
+		},
+	}
+
+	if err := util.DecodeOther(other, &cc); err != nil {
+		return nil, err
+	}
+
+	dev, err := config.Meters().ByName(cc.Battery)
+	if err != nil {
+		return nil, err
+	}
+
+	battery, ok := dev.Instance().(ChargeableBattery)
+	if !ok {
+		return nil, fmt.Errorf("'%s' is not a chargeable battery", cc.Battery)
+	}
+
+	c := &Battery{
+		embed:             &cc.embed,
+		ChargeableBattery: battery,
+	}
+
+	return c, nil
+}
+
+// Status calculates the battery charging status
+func (c *Battery) Status() (api.ChargeStatus, error) {
+	res := api.StatusB
+
+	p, err := c.ChargeableBattery.CurrentPower()
+	if p > 0 && err == nil {
+		res = api.StatusC
+	}
+
+	return res, err
+}
+
+// Enabled implements the api.Charger interface
+func (c *Battery) Enabled() (bool, error) {
+	return c.mode == api.BatteryCharge, nil
+}
+
+// Enable implements the api.Charger interface
+func (c *Battery) Enable(enable bool) error {
+	mode := api.BatteryNormal
+	if enable {
+		mode = api.BatteryCharge
+	}
+
+	// TODO handle locking of battery
+	err := c.ChargeableBattery.SetBatteryMode(mode)
+	if err == nil {
+		c.mode = mode
+	}
+
+	return err
+}
+
+// MaxCurrent implements the api.Charger interface
+func (c *Battery) MaxCurrent(current int64) error {
+	return nil
+}
+
+var _ api.Meter = (*Battery)(nil)
+
+// CurrentPower implements the api.Meter interface
+func (c *Battery) CurrentPower() (float64, error) {
+	if c.mode != api.BatteryCharge {
+		// disabled
+		return 0, nil
+	}
+	res, err := c.ChargeableBattery.CurrentPower()
+	return max(-res, 0), err
+}