diff --git a/src/main/java/de/ph87/data/series/Alignment.java b/src/main/java/de/ph87/data/series/Alignment.java
index 047c8b5..d011ee3 100644
--- a/src/main/java/de/ph87/data/series/Alignment.java
+++ b/src/main/java/de/ph87/data/series/Alignment.java
@@ -53,7 +53,7 @@ public enum Alignment {
     } else if (this.amount instanceof final Period period) {
       return period.multipliedBy((int) amount);
     }
-    throw new RuntimeException();
+    throw new RuntimeException("Cannot multiply unimplemented TemporalAmount: %s".formatted(this.amount));
   }
 
 }
diff --git a/src/main/java/de/ph87/data/series/graph/GraphPoint.java b/src/main/java/de/ph87/data/series/graph/GraphPoint.java
index c5228c7..b171a54 100644
--- a/src/main/java/de/ph87/data/series/graph/GraphPoint.java
+++ b/src/main/java/de/ph87/data/series/graph/GraphPoint.java
@@ -14,7 +14,7 @@ public class GraphPoint {
   @NonNull
   public GraphPoint plus(@NonNull final GraphPoint other) {
     if (this.date.compareTo(other.date) != 0) {
-      throw new RuntimeException();
+      throw new RuntimeException("Cannot 'add' GraphPoints with different dates: this=%s, other=%s".formatted(this, other));
     }
     return new GraphPoint(date, value + other.value);
   }
diff --git a/src/main/java/de/ph87/data/series/meter/MeterValue.java b/src/main/java/de/ph87/data/series/meter/MeterValue.java
index 26484f7..f36b42b 100644
--- a/src/main/java/de/ph87/data/series/meter/MeterValue.java
+++ b/src/main/java/de/ph87/data/series/meter/MeterValue.java
@@ -31,10 +31,8 @@ public abstract class MeterValue {
 
   public void update(@NonNull final Value value) {
     final double converted = value.as(id.getMeter().getSeries().getUnit()).value;
-    if (converted < this.max) {
-      throw new RuntimeException();
-    }
-    this.max = converted;
+    this.min = Math.min(this.min, converted);
+    this.max = Math.max(this.max, converted);
   }
 
   @Data