weeboludo

Hi, I'm designing my first system for a friend and I will have a few questions I hope you can advise on, but first I wanted to ask about backup power. The system is DVR & 7-8 external cameras with IR. I had a bash calculating the backup time: 8 Cameras at 12Vcc 450mA ... 8 * 12 * 0.45 = 50W From website, the DVR consumes 25W Total for system: 75W Looking for a random example, I found the DirectUPS DP1000 1000VA 600 Watts UPS at more or less US$100 .... Does this really mean: 600 / 75 ( * 0.9 for perfromance) == Around 7 hours This is way more than I expected. Have I gone wrong in the calculations?? Creating an entire closed loop power circuit for the cameras seems like alot of work - though I'll have to lay the signal cable anyway. Any really strong argument for having perhaps 3 smaller UPS rather than 1 big one? Thanks in advance for any advice

Been a while, but thought I'd report back. Went to a store specialising in CCTV systems and They have the following UPS: http://www.argseguridad.com/producto_detalle.php?id=459 With 1 x 4A output, 4 x 1A outputs and claims to run for 5 hours. The cameras were about 0.5A so I imagine I could connect 2 to each 1A output. The price is equivalent to 200 US or 130 pounds. They recommended coaxial cable with power cables incorporated, and said using passive baluns that the cables could stretch up to 100m without losing too much signal. The standalone linux system they have powers up automatically on hard shutdown.

Thought I had to be wrong. Cheers for the calculator, unfortunately available equipment here (Argentina) is pretty limited, not sure if any models I see are on this, so I'll have to get my pen & paper out. Thanks for the advice on cables & wiring ... that was going to be my next post once I understand the backup power requirements and once I have some measurements of the distances.

If it's a Windows-base DVR, you can install the UPS software that will monitor the UPS status and initiate a proper shutdown automatically when the power gets low. The idea was a standalone Linux based DVR, running without monitor. There will be power outages, and they will drain the battery completely and there will be noone around to reset it. So .. I'll be wanting somehting with BIOS wake ... wake-on-lan or something. I'm fairly handy with Linux, so as long as it will wake up and connect to the internet I am happy entering the system myself by SSH and fixing anything by hand. So either wake-on-lan or some BIOS setting. Though maybe I might have to build a system myself rather than buy a standalone (later I'll maybe ask you all for opinions on the models available here to see if you have experiences) Cheers

Good point, I'll have a look around see if I can find something similar available around here. Cheers