#1 Can I have the base of the system in another room than where is the router? without a cord plugged in the router at all times?
VMS4130 The base unit can be in any room, but it does require an Ethernet cabled connection directly to your router.
#2 How do you know when to change/charge the batteries and how long does it take to charge? What is the life of the battery?
VMS4000 The Arlo Pro batteries last 4 to 6 months with average use. Charging from 0% to 100% while inside the camera takes approximately 2.5 hours. There is an indicator light on the camera when fully charged. You can also view your battery levels in the Arlo app.
#3 Can you use usb storage instead of cloud storage? is there a size limit to the usb storage?
VMS4130 USB storage cannot replace cloud storage; it can only be used as a backup for your recordings. The current USB local storage device maximum supported size is 1TB.