Unattended patch install from remote machine

Hi Friends,

I am planning to apply SQL server 2008 R2 SP3 on 50 instances.

But we don't have WSUS in our environment.

So can you please suggest how to apply SP3 (unattended installation) on 50 instances simultaneously using CMD or PowerShell through work station?

Please share your thought asap.

thanks in advance.

Regards,

Nik

Regards, Naman