diff --git a/csharp/Lib/Devices/Battery48TL/Battery48TlRecord.Api.cs b/csharp/Lib/Devices/Battery48TL/Battery48TlRecord.Api.cs
index ec8bdf9e7..29a35e283 100644
--- a/csharp/Lib/Devices/Battery48TL/Battery48TlRecord.Api.cs
+++ b/csharp/Lib/Devices/Battery48TL/Battery48TlRecord.Api.cs
@@ -20,7 +20,7 @@ public partial class Battery48TlRecord
     public Boolean Eoc              => Leds is { Green: On, Amber: Off, Blue : Off };
 
     
-    public String SerialNumber => $"{_SerialNum1:X4} {_SerialNum2:X4} {_SerialNum3:X4} {_SerialNum4:X4}".TrimStart('0');
+    public String SerialNumber => $"{_SerialNum1:X4}{_SerialNum2:X4}{_SerialNum3:X4}{_SerialNum4:X4}".TrimEnd('0');
 
     public String  FwVersion    => _FwVersion.ToString("X4"); 
     public Strings Warnings     => ParseWarnings().OrderBy(w => w).ToList();
@@ -219,5 +219,4 @@ public partial class Battery48TlRecord
             return Math.Min(pLimit, 0);
         }
     }
-}
-
+}
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