I currently have 6 8 Channel DVR's - Link here
If you click on specs it shows the power required is
AC 90V ~ 260V, 65W.
I am wanting to backup these with a battery backup (or multiple). Can someone help me determine how many battery backups I will need, and what voltage/wattage? I would also like you to explain how you came up with the answer so I understand. I really appreciate it in advance.