diff --git a/src/actor.rs b/src/actor.rs
index 0f6903c..eae69ac 100644
--- a/src/actor.rs
+++ b/src/actor.rs
@@ -33,6 +33,7 @@ impl Plugin for ActorPlugin {
         ));
         app.add_systems(FixedUpdate, (
             update_physics_lifeforms,
+            update_power,
             handle_wants_maxrotation,
             handle_wants_maxvelocity,
         ));
@@ -198,21 +199,58 @@ impl Default for Engine {
 #[derive(Component)]
 pub struct Suit {
     pub oxygen: f32,
-    pub power: f32,
     pub oxygen_max: f32,
-    pub power_max: f32,
     pub integrity: f32, // [0.0 - 1.0]
 }
 impl Default for Suit { fn default() -> Self { SUIT_SIMPLE } }
 
 const SUIT_SIMPLE: Suit = Suit {
-    power: 1e5,
-    power_max: 1e5,
     oxygen: nature::OXY_D,
     oxygen_max: nature::OXY_D,
     integrity: 1.0,
 };
 
+#[derive(Component)]
+pub struct Battery {
+    pub power: f32, // Watt-seconds
+    pub capacity: f32, // Watt-seconds
+    pub reactor: f32, // Watt (production)
+}
+
+impl Default for Battery {
+    fn default() -> Self {
+        Self {
+            power: 10e3 * 3600.0,
+            capacity: 10e3 * 3600.0, // 10kWh
+            reactor: 2000e3, // 2MW
+        }
+    }
+}
+
+pub fn update_power(
+    time: Res<Time>,
+    mut settings: ResMut<var::Settings>,
+    mut q_battery: Query<(&mut Battery, Option<&Player>)>,
+    mut q_flashlight: Query<&mut Visibility, With<PlayersFlashLight>>,
+    mut ew_sfx: EventWriter<audio::PlaySfxEvent>,
+) {
+    let d = time.delta_seconds();
+    for (mut battery, player) in &mut q_battery {
+        if player.is_some() && settings.flashlight_active {
+            battery.power -= 4000000.0 * d;
+            if battery.power <= 0.0 {
+                settings.flashlight_active = false;
+                ew_sfx.send(audio::PlaySfxEvent(audio::Sfx::Click));
+                for mut flashlight_vis in &mut q_flashlight {
+                    *flashlight_vis = Visibility::Hidden;
+                }
+            }
+        }
+        battery.power = (battery.power + battery.reactor * d)
+            .clamp(0.0, battery.capacity);
+    }
+}
+
 pub fn update_physics_lifeforms(
     time: Res<Time>,
     mut query: Query<(&mut LifeForm, &mut HitPoints, &mut Suit, &LinearVelocity)>,
@@ -344,6 +382,7 @@ pub fn handle_input(
 
 pub fn handle_vehicle_enter_exit(
     mut commands: Commands,
+    mut settings: ResMut<var::Settings>,
     mut er_vehicle: EventReader<VehicleEnterExitEvent>,
     mut q_playerflashlight: Query<&mut Visibility, (With<PlayersFlashLight>, Without<ActorVehicleBeingEntered>, Without<ActorEnteringVehicle>)>,
     mut q_drivers: Query<(Entity, &mut Visibility, Option<&Collider>), (Without<ActorVehicleBeingEntered>, With<ActorEnteringVehicle>)>,
@@ -373,6 +412,7 @@ pub fn handle_vehicle_enter_exit(
                             commands.entity(vehicle).insert(PlayerDrivesThis);
                             if let Ok(mut flashlight_vis) = q_playerflashlight.get_single_mut() {
                                 *flashlight_vis = Visibility::Hidden;
+                                settings.flashlight_active = false;
                             }
                         }
                         else {
diff --git a/src/commands.rs b/src/commands.rs
index 86f020c..44dc715 100644
--- a/src/commands.rs
+++ b/src/commands.rs
@@ -683,6 +683,7 @@ fn spawn_entities(
                     integrity: state.suit_integrity,
                     ..default()
                 });
+                actor.insert(actor::Battery::default());
             }
             if state.is_clickable {
                 actor.insert(hud::IsClickable {
diff --git a/src/hud.rs b/src/hud.rs
index cff9800..a2486b9 100644
--- a/src/hud.rs
+++ b/src/hud.rs
@@ -685,7 +685,7 @@ fn update_speedometer(
 
 fn update_gauges(
     timer: ResMut<FPSUpdateTimer>,
-    q_player: Query<(&actor::HitPoints, &actor::Suit), With<actor::Player>>,
+    q_player: Query<(&actor::HitPoints, &actor::Suit, &actor::Battery), With<actor::Player>>,
     mut q_gauges: Query<(&mut Style, &mut BackgroundColor, &Gauge, &GaugeLength)>,
     settings: Res<var::Settings>,
 ) {
@@ -694,14 +694,14 @@ fn update_gauges(
     }
     let player = q_player.get_single();
     if player.is_err() { return; }
-    let (hp, suit) = player.unwrap();
+    let (hp, suit, battery) = player.unwrap();
 
     for (mut style, mut bg, gauge, len) in &mut q_gauges {
         let value: f32 = match gauge {
             Gauge::Health => hp.current / hp.max,
             Gauge::Oxygen => (suit.oxygen / suit.oxygen_max).powf(0.5),
             Gauge::Integrity => suit.integrity,
-            Gauge::Power => suit.power / suit.power_max,
+            Gauge::Power => battery.power / battery.capacity,
         };
         if value < 0.5 {
             *bg = settings.hud_color_alert.into();