diff --git a/js/ui/endSessionDialog.js b/js/ui/endSessionDialog.js
index 00dd9b220..ebf4f4d81 100644
--- a/js/ui/endSessionDialog.js
+++ b/js/ui/endSessionDialog.js
@@ -18,7 +18,7 @@
  */
 
 const { AccountsService, Clutter, Gio,
-        GLib, GObject, Pango, Polkit, Shell, St }  = imports.gi;
+        GLib, GObject, Pango, Polkit, Shell, St, UPowerGlib: UPower }  = imports.gi;
 
 const CheckBox = imports.ui.checkBox;
 const Dialog = imports.ui.dialog;
@@ -31,6 +31,8 @@ const { loadInterfaceXML } = imports.misc.fileUtils;
 
 const _ITEM_ICON_SIZE = 64;
 
+const LOW_BATTERY_THRESHOLD = 30;
+
 const EndSessionDialogIface = loadInterfaceXML('org.gnome.SessionManager.EndSessionDialog');
 
 const logoutDialogContent = {
@@ -157,7 +159,7 @@ const LogindSession = Gio.DBusProxy.makeProxyWrapper(LogindSessionIface);
 const PkOfflineIface = loadInterfaceXML('org.freedesktop.PackageKit.Offline');
 const PkOfflineProxy = Gio.DBusProxy.makeProxyWrapper(PkOfflineIface);
 
-const UPowerIface = loadInterfaceXML('org.freedesktop.UPower');
+const UPowerIface = loadInterfaceXML('org.freedesktop.UPower.Device');
 const UPowerProxy = Gio.DBusProxy.makeProxyWrapper(UPowerIface);
 
 function findAppFromInhibitor(inhibitor) {
@@ -244,7 +246,7 @@ class EndSessionDialog extends ModalDialog.ModalDialog {
 
         this._powerProxy = new UPowerProxy(Gio.DBus.system,
                                            'org.freedesktop.UPower',
-                                           '/org/freedesktop/UPower',
+                                           '/org/freedesktop/UPower/devices/DisplayDevice',
                                            (proxy, error) => {
                                                if (error) {
                                                    log(error.message);
@@ -279,7 +281,7 @@ class EndSessionDialog extends ModalDialog.ModalDialog {
 
         this._batteryWarning = new St.Label({
             style_class: 'end-session-dialog-battery-warning',
-            text: _('Running on battery power: Please plug in before installing updates.'),
+            text: _('Low battery power: please plug in before installing updates.'),
         });
         this._batteryWarning.clutter_text.ellipsize = Pango.EllipsizeMode.NONE;
         this._batteryWarning.clutter_text.line_wrap = true;
@@ -329,6 +331,32 @@ class EndSessionDialog extends ModalDialog.ModalDialog {
         this._user.disconnect(this._userChangedId);
     }
 
+    _isDischargingBattery() {
+        return this._powerProxy.IsPresent &&
+            this._powerProxy.State !== UPower.DeviceState.CHARGING &&
+            this._powerProxy.State !== UPower.DeviceState.FULLY_CHARGED;
+    }
+
+    _isBatteryLow() {
+        return this._isDischargingBattery() && this._powerProxy.Percentage < LOW_BATTERY_THRESHOLD;
+    }
+
+    _shouldShowLowBatteryWarning(dialogContent) {
+        if (!dialogContent.showBatteryWarning)
+            return false;
+
+        if (!this._isBatteryLow())
+            return false;
+
+        if (this._checkBox.checked)
+            return true;
+
+        // Show the warning if updates have already been triggered, but
+        // the user doesn't have enough permissions to cancel them.
+        let updatesAllowed = this._updatesPermission && this._updatesPermission.allowed;
+        return this._updateInfo.UpdatePrepared && this._updateInfo.UpdateTriggered && !updatesAllowed;
+    }
+
     _sync() {
         let open = this.state == ModalDialog.State.OPENING || this.state == ModalDialog.State.OPENED;
         if (!open)
@@ -342,10 +370,7 @@ class EndSessionDialog extends ModalDialog.ModalDialog {
         if (dialogContent.subjectWithUpdates && this._checkBox.checked)
             subject = dialogContent.subjectWithUpdates;
 
-        if (dialogContent.showBatteryWarning) {
-            this._batteryWarning.visible =
-                this._powerProxy.OnBattery && this._checkBox.checked;
-        }
+        this._batteryWarning.visible = this._shouldShowLowBatteryWarning(dialogContent);
 
         let description;
         let displayTime = _roundSecondsToInterval(this._totalSecondsToStayOpen,
@@ -748,19 +773,17 @@ class EndSessionDialog extends ModalDialog.ModalDialog {
         if (dialogContent.showOtherSessions)
             this._loadSessions();
 
-        let updateTriggered = this._updateInfo.UpdateTriggered;
-        let updatePrepared = this._updateInfo.UpdatePrepared;
         let updatesAllowed = this._updatesPermission && this._updatesPermission.allowed;
 
         _setCheckBoxLabel(this._checkBox, dialogContent.checkBoxText || '');
-        this._checkBox.visible = dialogContent.checkBoxText && updatePrepared && updatesAllowed;
-        this._checkBox.checked = this._checkBox.visible;
+        this._checkBox.visible = dialogContent.checkBoxText && this._updateInfo.UpdatePrepared && updatesAllowed;
 
-        // We show the warning either together with the checkbox, or when
-        // updates have already been triggered, but the user doesn't have
-        // enough permissions to cancel them.
-        this._batteryWarning.visible = dialogContent.showBatteryWarning &&
-                                        (this._checkBox.visible || updatePrepared && updateTriggered && !updatesAllowed);
+        if (this._type === DialogType.UPGRADE_RESTART)
+            this._checkBox.checked = this._checkBox.visible && this._updateInfo.UpdateTriggered && !this._isDischargingBattery();
+        else
+            this._checkBox.checked = this._checkBox.visible && !this._isBatteryLow();
+
+        this._batteryWarning.visible = this._shouldShowLowBatteryWarning(dialogContent);
 
         this._updateButtons();