Fix BullTron discharge display and disconnect

tests/test_bulltron_gui.py

@@ -42,7 +42,7 @@ class BullTronParserTest(unittest.TestCase):
         self.assertTrue(state.telemetry.charge_mos)
         self.assertTrue(state.telemetry.discharge_mos)
         self.assertEqual(state.telemetry.cell_count, 4)
-        self.assertEqual(state.telemetry.time_value, "9 h 21 m")
+        self.assertEqual(state.telemetry.time_value, "14 h 20 m")
 
     def test_charging_time_uses_soc_fraction_and_rated_capacity(self):
         state = DeviceState(rated_capacity_ah=160)
@@ -51,7 +51,7 @@ class BullTronParserTest(unittest.TestCase):
         words[41] = 30152
         words[42] = 450
         words[47] = 1
-        words[48] = 72
+        words[48] = 720
         payload = b"".join(word.to_bytes(2, "big") for word in words)
         body = bytes([0xD2, 0x03, len(payload)]) + payload
         from bulltron_gui import crc16_modbus_swapped
@@ -64,6 +64,50 @@ class BullTronParserTest(unittest.TestCase):
         self.assertEqual(state.telemetry.time_label, "Time till full")
         self.assertEqual(state.telemetry.time_value, "5 h 47 m")
 
+    def test_current_direction_uses_signed_current_for_display(self):
+        state = DeviceState(rated_capacity_ah=160)
+        words = [0] * 62
+        words[40] = 128
+        words[41] = 29922
+        words[42] = 490
+        words[47] = 1
+        words[48] = 784
+        payload = b"".join(word.to_bytes(2, "big") for word in words)
+        body = bytes([0xD2, 0x03, len(payload)]) + payload
+        from bulltron_gui import crc16_modbus_swapped
+
+        frame = body + crc16_modbus_swapped(body).to_bytes(2, "big")
+        decode_response(frame, state)
+        self.assertAlmostEqual(state.telemetry.current, -7.8)
+        self.assertAlmostEqual(state.telemetry.discharge_current, 7.8)
+        self.assertAlmostEqual(state.telemetry.discharge_power_w, 99.84)
+        self.assertAlmostEqual(state.telemetry.charge_current, 0.0)
+        self.assertEqual(state.telemetry.time_label, "Time till empty")
+        self.assertEqual(state.telemetry.time_value, "10 h 03 m")
+
+    def test_bms_residue_time_register_overrides_estimate(self):
+        state = DeviceState(rated_capacity_ah=160)
+        residue_payload = (6 * 60 + 30).to_bytes(2, "big")
+        residue_body = bytes([0xD2, 0x03, len(residue_payload)]) + residue_payload
+        from bulltron_gui import crc16_modbus_swapped
+
+        residue_frame = residue_body + crc16_modbus_swapped(residue_body).to_bytes(2, "big")
+        decode_response(residue_frame, state)
+
+        words = [0] * 62
+        words[40] = 128
+        words[41] = 29999
+        words[42] = 490
+        words[47] = 2
+        words[48] = 784
+        payload = b"".join(word.to_bytes(2, "big") for word in words)
+        body = bytes([0xD2, 0x03, len(payload)]) + payload
+        live_frame = body + crc16_modbus_swapped(body).to_bytes(2, "big")
+        decode_response(live_frame, state)
+
+        self.assertEqual(state.telemetry.time_label, "Time till empty")
+        self.assertEqual(state.telemetry.time_value, "6 h 30 m")
+
     def test_settings_capacity_uses_app_word_zero(self):
         state = DeviceState()
         words = [1600, 3750, 42] + [0] * 38