Sorry i found How
$yearStart = Get-Date -Day 1 -Month 12 -Year 2012 -Hour 0 -Minute 0 -Second 0
$months = 11
$vms = Get-VM VM*
&{0..($months-1) | %{
$start = $yearStart.AddMonths($_)
$finish = $start.AddMonths(1).AddSeconds(-1)
Get-VMUptime -VM $vms -Start $start -Finish $finish
}} |
Export-Csv C:\scriptvm\uptime\uptime.csv -NoTypeInformation -UseCulture
on luc website.;)