diff --git a/web/db.py b/web/db.py
index 28a7caf..6654a23 100644
--- a/web/db.py
+++ b/web/db.py
@@ -140,15 +140,6 @@ class Database:
             return None
         return res[0]
 
-    @staticmethod
-    def get_range_timestamp():
-        conn = Database.get_db()
-        first = conn.execute("SELECT Timestamp FROM position ORDER BY Timestamp limit 1").fetchone()
-        last = conn.execute("SELECT Timestamp FROM position ORDER BY Timestamp DESC limit 1").fetchone()
-        if first is None or last is None:
-            return None, None
-        return first[0], last[0]
-
     @staticmethod
     def set_chargings_price(conn, start_at, price):
         if isinstance(start_at, str):
diff --git a/web/views.py b/web/views.py
index daf677e..008699a 100644
--- a/web/views.py
+++ b/web/views.py
@@ -240,23 +240,34 @@ def after_request(response):
 
 
 def update_trips():
-    global trips, chargings, cached_layout
+    global trips, chargings, cached_layout, min_date, max_date, min_millis, max_millis, step, marks
     logger.info("update_data")
     Database.add_altitude_to_db(Database.get_db(update_callback=False))
+    min_date = None
+    max_date = None
     try:
         trips_by_vin = Trips.get_trips(myp.vehicles_list)
         trips = next(iter(trips_by_vin.values()))  # todo handle multiple car
         assert len(trips) > 0
-        chargings = Charging.get_chargings()
+        min_date = trips[0].start_at
+        max_date = trips[-1].start_at
     except (StopIteration, AssertionError):
         logger.debug("No trips yet")
-        # return
-    # update for slider
-    global min_date, max_date, min_millis, max_millis, step, marks
     try:
-        # min_date = trips[0].start_at
-        # max_date = trips[-1].start_at
-        min_date, max_date = Database.get_range_timestamp()
+        chargings = Charging.get_chargings()
+        assert len(chargings) > 0
+        if min_date:
+            min_date = min(min_date, chargings[0]["start_at"])
+            max_date = max(max_date, chargings[-1]["start_at"])
+        else:
+            min_date = chargings[0]["start_at"]
+            max_date = chargings[-1]["start_at"]
+    except AssertionError:
+        logger.debug("No chargings yet")
+    if min_date is None:
+        return
+    # update for slider
+    try:
         logger.debug("min_date:%s - max_date:%s",min_date, max_date)
         min_millis = figures.unix_time_millis(min_date)
         max_millis = figures.unix_time_millis(max_date)
@@ -269,7 +280,6 @@ def update_trips():
         logger.debug("position table is probably empty :", exc_info=True)
     return
 
-
 def __get_control_tabs():
     tabs = []
     for car in myp.vehicles_list: