[Chartjs]-Time series stream, removing am/pm on x axis and 24 hour format

The Chart.js docs you linked to specify this structure for formatting time axes labels:

time: {
    displayFormats: {
        quarter: 'MMM YYYY'
    }
}

so plugging in your format that becomes:

time: {
    displayFormats: {
        second: this.timeFormat
    }
}

You were right, just a tiny detail! (updated Fiddle).