diff --git a/bumblebee/module.py b/bumblebee/module.py
index 4b3811b..11549a5 100644
--- a/bumblebee/module.py
+++ b/bumblebee/module.py
@@ -6,6 +6,12 @@ class Module(object):
     def data(self):
         pass
 
+    def critical(self):
+        return False
+
+    def warning(self):
+        return False
+
     def state(self):
         return "default"
 
diff --git a/bumblebee/modules/battery.py b/bumblebee/modules/battery.py
index abe0a68..2c779e8 100644
--- a/bumblebee/modules/battery.py
+++ b/bumblebee/modules/battery.py
@@ -18,7 +18,15 @@ class Module(bumblebee.module.Module):
         with open("/sys/class/power_supply/{}/status".format(self._battery)) as f:
             self._status = f.read().strip()
         if self._status == "Discharging":
-            return "discharging"
+            if self._capacity < 10:
+                return "discharging_critical"
+            if self._capacity < 25:
+                return "discharging_low"
+            if self._capacity < 50:
+                return "discharging_medium"
+            if self._capacity < 75:
+                return "discharging_high"
+            return "discharging_full"
         else:
             return "charging"
 # vim: tabstop=8 expandtab shiftwidth=4 softtabstop=4
diff --git a/bumblebee/outputs/i3.py b/bumblebee/outputs/i3.py
index eec156e..63bbeed 100644
--- a/bumblebee/outputs/i3.py
+++ b/bumblebee/outputs/i3.py
@@ -20,6 +20,10 @@ class i3bar(bumblebee.output.Output):
             "color": theme.color(obj),
             "background": theme.background(obj),
         }
+
+        if theme.urgent(obj) and obj.critical():
+            data["urgent"] = True
+
         if theme.default_separators(obj) == False:
             data["separator"] = False
             data["separator_block_width"] = 0
diff --git a/bumblebee/theme.py b/bumblebee/theme.py
index e7f7776..6cf115d 100644
--- a/bumblebee/theme.py
+++ b/bumblebee/theme.py
@@ -37,6 +37,9 @@ class Theme:
         self._previous_background = None
         self._background = None
 
+    def urgent(self, obj):
+        self._gettheme(obj, "urgent")
+
     def next(self):
         self._cycle_index += 1
         self._previous_background = self._background
@@ -44,10 +47,25 @@ class Theme:
             self._cycle_index = 0
 
     def color(self, obj):
-        return self._gettheme(obj, "fg")
+        fg = None
+        if obj.warning():
+            fg = self._gettheme(obj, "fg-warning")
+        if obj.critical():
+            fg = self._gettheme(obj, "fg-critical")
+        if fg == None:
+            fg = self._gettheme(obj, "fg")
+        return fg
 
     def background(self, obj):
-        self._background = self._gettheme(obj, "bg")
+        self._background = None
+        if obj.warning():
+            self._background = self._gettheme(obj, "bg-warning")
+        if obj.critical():
+            self._background = self._gettheme(obj, "bg-critical")
+
+        if self._background == None:
+            self._background = self._gettheme(obj, "bg")
+
         return self._background
 
     def previous_background(self):
diff --git a/bumblebee/themes/default.json b/bumblebee/themes/default.json
index 09fdcdd..cb05338 100644
--- a/bumblebee/themes/default.json
+++ b/bumblebee/themes/default.json
@@ -1,5 +1,6 @@
 {
 	"defaults": {
+		"urgent": true,
 		"prefix": " ",
 		"suffix" : " ",
 		"cycle": [