I have implemented "Battery icon" in the form of progress bar that updates battery status dynamically. But its not reflecting in battery icon.

<Grid Width="50" Height="30" HorizontalAlignment="Left" Margin="0,0,-18,0">
                    <ProgressBar Style="{DynamicResource ProgressBar}" x:Name="BatteryStatus1" HorizontalContentAlignment="Stretch" VerticalContentAlignment="Stretch" VerticalAlignment="Top"  SnapsToDevicePixels="True"  Background="Black" Margin="0" Height="20" Width="35" Value="{Binding BataryValue}">
                        <ProgressBar.ToolTip >
                            <ToolTip Placement="Bottom" Visibility="Visible">
                                <StackPanel>
                                    <!--<Label Content="50% remaining/ available (plugged in , charging)"/>-->
                                    <StackPanel Orientation="Vertical">
                                        <TextBlock Text="Power Availability : "/>
                                        <TextBlock Text="{Binding BataryValue}"/>
                                        <TextBlock Text="%"/>
                                    </StackPanel>
                                    <StackPanel Orientation="Vertical">
                                        <TextBlock Text="Remaining Time : "/>
                                        <TextBlock Text="{Binding BataryValue}"/>
                                        <TextBlock Text="min"/>
                                    </StackPanel>
                                </StackPanel>
                            </ToolTip>
                        </ProgressBar.ToolTip>
                    </ProgressBar>
                </Grid>

namespace WpfApplication3
{
    /// <summary>
    /// Interaction logic for MainWindow.xaml
    /// </summary>
    public partial class MainWindow : Window, INotifyPropertyChanged
    {
        public MainWindow()
        {
            InitializeComponent();

            this.DataContext = this;

            BataryValue = 100;

            System.Timers.Timer timer = new System.Timers.Timer(1000d);

            timer.Elapsed += new ElapsedEventHandler(timer_Elapsed);

            timer.Start();
        }

        public double BataryValue { get; set; }

        void timer_Elapsed(object sender, ElapsedEventArgs e)
        {
            this.Dispatcher.BeginInvoke(DispatcherPriority.Normal, new Action(() => { this.BataryValue -= 1; NotifyPropertyChanged("BataryValue"); }));
        }


        private void NotifyPropertyChanged(String propertyName = "")
        {
            if (PropertyChanged != null)
            {
                PropertyChanged(this, new PropertyChangedEventArgs(propertyName));
            }
        }

        public event PropertyChangedEventHandler PropertyChanged;

    }
}

<Style x:Key="ProgressBar" TargetType="ProgressBar">
           <Setter Property="Template">
               <Setter.Value>
                   <ControlTemplate TargetType="{x:Type ProgressBar}">
                       <Grid x:Name="BataryStatus" Height="20" Width="38" Background="Black">
                           <Rectangle Stroke="White" Margin="0,0,6,0" />
                           <Rectangle Fill="White" HorizontalAlignment="right" Margin="0,4"/>
                           <Rectangle Fill="White" Stroke="White" HorizontalAlignment="Right" Margin="0,4" Width="5" />
                           <Rectangle Fill="White" Stroke="White" HorizontalAlignment="Left" Margin="3,2,0,2" Width="5" />
                           <Rectangle Fill="White" Stroke="White" HorizontalAlignment="Left" Margin="10,2,0,2" Width="5" />
                           <Rectangle Fill="White" Stroke="White" HorizontalAlignment="Left" Margin="17,2,0,2" Width="5" />
                           <Rectangle Fill="White" Stroke="White" HorizontalAlignment="Right" Margin="0,2,16,2" Width="5" />
                           <Rectangle Fill="White" Stroke="White" HorizontalAlignment="Right" Margin="0,2,9,2" Width="5" />
                       </Grid>
                   </ControlTemplate>
               </Setter.Value>
           </Setter>
       </Style>