diff --git a/meter/sma.go b/meter/sma.go
index 3ebc0d61a..c412a7653 100644
--- a/meter/sma.go
+++ b/meter/sma.go
@@ -109,7 +109,10 @@ func (sm *SMA) receive() {
 				sm.updated = time.Now()
 			}
 		} else if power, ok := msg.Values[sma.ExportPower]; ok {
-			sm.power = -power
+			sm.power = 0
+			if power > 0 {
+				sm.power = -power
+			}
 			sm.updated = time.Now()
 		} else if power, ok := msg.Values[sma.ImportPower]; ok {
 			sm.power = power
diff --git a/meter/sma/listener.go b/meter/sma/listener.go
index c97e24de1..9297ca233 100644
--- a/meter/sma/listener.go
+++ b/meter/sma/listener.go
@@ -157,6 +157,8 @@ func (l *Listener) processMessage(src *net.UDPAddr, b []byte) (Telegram, error)
 		Values: obisValues,
 	}
 
+	//	l.log.TRACE.Printf("recv %v", msg.Values)
+
 	return msg, nil
 }
 
diff --git a/meter/sma/listener_test.go b/meter/sma/listener_test.go
index 1d92af471..56b0552ab 100644
--- a/meter/sma/listener_test.go
+++ b/meter/sma/listener_test.go
@@ -4,6 +4,8 @@ import (
 	"net"
 	"reflect"
 	"testing"
+
+	"github.com/andig/evcc/util"
 )
 
 func TestListenerProcessMessage(t *testing.T) {
@@ -186,7 +188,9 @@ func TestListenerProcessMessage(t *testing.T) {
 	}
 	for _, tc := range tests {
 		t.Run(tc.name, func(t *testing.T) {
-			l := &Listener{}
+			l := &Listener{
+				log: util.NewLogger("sma "),
+			}
 
 			buffer := tc.response
 			read := len(buffer)