diff --git a/bmspy/classes.py b/bmspy/classes.py
new file mode 100644
index 0000000..85f8a73
--- /dev/null
+++ b/bmspy/classes.py
@@ -0,0 +1,39 @@
+from dataclasses import dataclass, fields as dataclass_fields
+
+
+@dataclass
+class BMSScalarField:
+    """Single numeric or boolean measurement"""
+
+    help: str
+    raw_value: float | bool
+    value: str
+    units: str | None = None
+
+    def get(self, key, default=None):
+        return getattr(self, key, default)
+
+
+@dataclass
+class BMSMultiField:
+    """Indexed collection (cells, temperature sensors)"""
+
+    help: str
+    label: str
+    raw_values: dict
+    values: dict
+    units: str | None = None
+
+    def get(self, key, default=None):
+        return getattr(self, key, default)
+
+
+@dataclass
+class BMSInfoField:
+    """Text / date info (non-numeric)"""
+
+    help: str
+    info: str
+
+    def get(self, key, default=None):
+        return getattr(self, key, default)
diff --git a/bmspy/jbd_ups.py b/bmspy/jbd_ups.py
index 4b6addd..a6e2d6e 100644
--- a/bmspy/jbd_ups.py
+++ b/bmspy/jbd_ups.py
@@ -8,43 +8,7 @@ import serial.rs485
 import time
 from dataclasses import dataclass, fields as dataclass_fields
 
-
-@dataclass
-class BMSScalarField:
-    """Single numeric or boolean measurement"""
-
-    help: str
-    raw_value: float | bool
-    value: str
-    units: str | None = None
-
-    def get(self, key, default=None):
-        return getattr(self, key, default)
-
-
-@dataclass
-class BMSMultiField:
-    """Indexed collection (cells, temperature sensors)"""
-
-    help: str
-    label: str
-    raw_values: dict
-    values: dict
-    units: str | None = None
-
-    def get(self, key, default=None):
-        return getattr(self, key, default)
-
-
-@dataclass
-class BMSInfoField:
-    """Text / date info (non-numeric)"""
-
-    help: str
-    info: str
-
-    def get(self, key, default=None):
-        return getattr(self, key, default)
+from bmspy.classes import BMSScalarField, BMSMultiField, BMSInfoField
 
 
 @dataclass