UPS (Battery Backup)
A simple UPS (Uninterruptible Power Supply) battery backup device can ensure your CCTV system remains working in the event of a power cut.
The following times are a rough guide as to how long they can power a system for:
A 1500va unit will provide approximately 18-24 mins on a 4 camera system (mixed day and night), 8-18 mins on an 8 camera system.
If you are looking for longer times than this or for a 16 camera system, a 1500va unit is recommended for the DVR alone (providing up to about 45 minutes of run time) with an 800va unit per 4 cameras/a 1500va unit per 8 cameras.