How to use the modernizr.batteryapi function in modernizr

checkDeviceCapabilites() {
      this.hasWebGL              = Modernizr.webgl;
      this.hasWebGLExtensions    = Modernizr.webglextensions;
      this.hasSpeechSynthesis    = Modernizr.speechsynthesis;
      this.hasSpeechRecognition  = Modernizr.speechrecognition;
      this.hasBatteryAPI         = Modernizr.batteryapi;
      this.hasLowBattery         = Modernizr.lowbattery;
      this.hasLowBandwidth       = Modernizr.lowbandwidth;
    }