thermald: add minimum offroad time to low voltage shutdown (#26660)

* voltage cleanup thermald

* Fix voltage shutdown test

selfdrive/thermald/power_monitoring.py

@@ -18,6 +18,7 @@ VBATT_PAUSE_CHARGING = 11.0           # Lower limit on the LPF car battery volta
 VBATT_INSTANT_PAUSE_CHARGING = 7.0    # Lower limit on the instant car battery voltage measurements to avoid triggering on instant power loss
 MAX_TIME_OFFROAD_S = 30*3600
 MIN_ON_TIME_S = 3600
+VOLTAGE_SHUTDOWN_MIN_OFFROAD_TIME_S = 60
 
 class PowerMonitoring:
   def __init__(self):
@@ -114,8 +115,12 @@ class PowerMonitoring:
 
     now = sec_since_boot()
     should_shutdown = False
-    should_shutdown |= (now - offroad_timestamp) > MAX_TIME_OFFROAD_S
-    should_shutdown |= (self.car_voltage_mV < (VBATT_PAUSE_CHARGING * 1e3)) and (self.car_voltage_instant_mV > (VBATT_INSTANT_PAUSE_CHARGING * 1e3))
+    offroad_time = (now - offroad_timestamp)
+    low_voltage_shutdown = (self.car_voltage_mV < (VBATT_PAUSE_CHARGING * 1e3) and
+                            self.car_voltage_instant_mV > (VBATT_INSTANT_PAUSE_CHARGING * 1e3) and
+                            offroad_time > VOLTAGE_SHUTDOWN_MIN_OFFROAD_TIME_S)
+    should_shutdown |= offroad_time > MAX_TIME_OFFROAD_S
+    should_shutdown |= low_voltage_shutdown
     should_shutdown |= (self.car_battery_capacity_uWh <= 0)
     should_shutdown &= not ignition
     should_shutdown &= (not self.params.get_bool("DisablePowerDown"))

selfdrive/thermald/tests/test_power_monitoring.py

@@ -120,15 +120,19 @@ class TestPowerMonitoring(unittest.TestCase):
   def test_car_voltage(self):
     POWER_DRAW = 0 # To stop shutting down for other reasons
     TEST_TIME = 100
-    with pm_patch("HARDWARE.get_current_power_draw", POWER_DRAW):
+    VOLTAGE_SHUTDOWN_MIN_OFFROAD_TIME_S = 50
+    with pm_patch("VOLTAGE_SHUTDOWN_MIN_OFFROAD_TIME_S", VOLTAGE_SHUTDOWN_MIN_OFFROAD_TIME_S, constant=True), pm_patch("HARDWARE.get_current_power_draw", POWER_DRAW):
       pm = PowerMonitoring()
       pm.car_battery_capacity_uWh = CAR_BATTERY_CAPACITY_uWh
       ignition = False
+      start_time = ssb
       for i in range(TEST_TIME):
         pm.calculate(VOLTAGE_BELOW_PAUSE_CHARGING, ignition)
         if i % 10 == 0:
-          self.assertEqual(pm.should_shutdown(ignition, True, ssb, True), (pm.car_voltage_mV < VBATT_PAUSE_CHARGING*1e3))
-      self.assertTrue(pm.should_shutdown(ignition, True, ssb, True))
+          self.assertEqual(pm.should_shutdown(ignition, True, start_time, True),
+                           (pm.car_voltage_mV < VBATT_PAUSE_CHARGING*1e3 and
+                            (ssb - start_time) > VOLTAGE_SHUTDOWN_MIN_OFFROAD_TIME_S))
+      self.assertTrue(pm.should_shutdown(ignition, True, start_time, True))
 
   # Test to check policy of not stopping charging when DisablePowerDown is set
   def test_disable_power_down(self):