diff --git a/flent/tests/power_usage.conf b/flent/tests/power_usage.conf
index 7731e1f2..e04b3356 100644
--- a/flent/tests/power_usage.conf
+++ b/flent/tests/power_usage.conf
@@ -61,7 +61,8 @@ PLOTS = o([
            'cutoff': (DELAY,-DELAY)},
           {'data': 'mqtt_power',
            'label': 'Wall plug consumption',
-           'cutoff': (DELAY,-DELAY)},
+           'combine_mode': 'raw_max',
+           'raw_key': 'value'},
           ]}),
     ('cpu_runners',
      {'description': 'Number of CPU runners',