Backup Underwater Camera System

[fishcam10 0]

Hello,

I am designing a backup underwater camera system using 2 waterproof cameras, a 12 volt DVR, and (2) 20 watt 12V pond lights. I am trying to find a power supply or some type of switch in order to have this system in the "off" mode normally and then switch to battery power when our main 120 volt system power goes down. Any ideas?

Edited March 29, 2010 by Guest

[Soundy 1]

How long does it have to run for? You could just plug the whole thing into a standard UPS (uninterruptable power supply, not the courier).

 

Beyond that, something like this should do the trick: http://altronix.com/index.php?pid=2&model_num=AL1012ULXPD4CB

[survtech 0]

Do you have a primary system? If so you could back that up using Soundy's suggestion or a UPS.

 

If you only want a system that turns on when the main power fails, a simple relay could handle that. The relay's coil would be connected to the main 120VAC power and the normally closed contacts would be used to provide power to the system.

[Soundy 1]

Another option, if all the gear is 12V anyway, would be to simply run it all off a car battery (in a well-ventilated area, natch) and keep the battery topped up with a trickle charger, preferably the "smart" type.

[fishcam10 0]

Soundy,Survtech thanks for the replies. The system would have to run for about 1-2 hours on the battery. The primary system will run on 120V. The relay idea is what I was thinking so that the backup system would switch on when the 120V goes down. A regular UPS won't work because the system would have to have to be powered on all the time and then switch to battery when the main power went down. Any ideas for a relay?

[Soundy 1]

I'm not quite clear here... so you have two separate camera/recorder systems, one that runs on 120VAC, and another 12V one that you want to kick in when the power goes out?

 

Is there a specific reason for doing it this way, or is this just the way things have evolved? Two separate systems seems overly complicated and wasteful to me, especially if the 12V system will kick in only rarely - that's a lot of money (relatively) to put into something that will see only limited use.

 

Personally, I'd go one of two (and a half) ways:

 

1. Put the 120V system on a UPS to keep it running when the power goes out (although this would require a fairly hefty UPS for 1-2 hours, depending on the number of components and their power draw).

 

2. Use an all-12VDC solution, running either:

a. on a power supply with internal battery backup, like the Altronix shown above

b. on a deep-cycle car battery with a smart trickle charger

 

If power goes out regularly (I grew up in a rural area on a lake, I know how that can happen), I'd probably go with option 2. Option 1 is rather inefficient, especially since many standalone DVRs ultimately run on 12VDC anyway, and 12VDC cameras are cheap and plentiful - when on battery, you're basically stepping up 12VDC from the UPS's internal battery, to 120VAC, only for the cameras' and DVR's power adapters to drop it back down to 12VDC. That's a lot of wasted energy when you need to run it for a long period.

[fishcam10 0]

Soundy,

Yes, we decided to have two seperate systems because our main system will have 10 underwater cameras and 30 underwater lights and the draw on a UPS system seemed to be too much and very expensive. Our main system will record to computers in a office about 1000' feet away from the river. I was hoping to design a simple backup system closer to the river.

[survtech 0]

Any SPDT or DPDT relay with 120VAC coil and sufficient current capability should do.

 

Relays - 120V AC Coil:

 

http://www.poolandspa.com/catalog/product004454000376.cfm

 

You'll want to connect one leg of the 12VDC through the NC (normally closed) and Common contacts so that when 120VAC is applied, the connection is "open" (not connected). You also might want to put the relay inside a suitable electrical box.

[Soundy 1]

Soundy,

Yes, we decided to have two seperate systems because our main system will have 10 underwater cameras and 30 underwater lights and the draw on a UPS system seemed to be too much and very expensive. Our main system will record to computers in a office about 1000' feet away from the river. I was hoping to design a simple backup system closer to the river.

 

How about putting the recorder on a UPS (computers should be protected like that anyway), and power a few select cameras and lights on a battery system like those I suggested? They could run off the backed-up power supply or car-battery setup 24/7 and will simply keep going when the power goes out, while the others will shut off until power returns.

 

Again, it seems wasteful to have a whole separate system with separate lights and cameras that will be used only very rarely for very short periods.

[fishcam10 0]

How about putting the recorder on a UPS (computers should be protected like that anyway), and power a few select cameras and lights on a battery system like those I suggested? They could run off the backed-up power supply or car-battery setup 24/7 and will simply keep going when the power goes out, while the others will shut off until power returns

.

 

Soundy,

 

I think this is the way I am going to go. Thanks for all your help!