Example of how get battery status from device in Xamarin.Forms applications - http://julianocustodio.com/BatteryStatus

MainPage.xaml

<?xml version="1.0" encoding="utf-8" ?>
<ContentPage xmlns="http://xamarin.com/schemas/2014/forms"
             xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml"
             xmlns:local="clr-namespace:BatteryStatusDemo"
             x:Class="BatteryStatusDemo.MainPage">

    <StackLayout VerticalOptions="Center" 
                 HorizontalOptions="Center" >
        <Label x:Name="RemainingChargePercent"/>
        <Label x:Name="Status"/>
        <Label x:Name="PowerSource"/>
    </StackLayout>

</ContentPage>