Using PC power supply to power cameras

[amnon 0]

Are there any problems getting a 12V lead from the PC the DVR card is installed in, and powering the cameras?

[cachecreekcctv 0]

Probably not a good idea. Better to use a fused power source for all cameras. Each camera should have its' own overcurrent device (fuse, circuit breaker). Use a separate power supply with at least the capacity of 1 amp per camera. Will keep things a lot cooler that way, when the transformer is not overheating.

[scorpion 0]

I concur with CacheCreek!

 

 

Question:

If the camera goes out, and takes out the power supply, does this mean that your PC goes down also, or are you using the power supply as a standalone source?

[zmxtech 0]

good idea but flawed unless you have very fancy circuit breakers.

 

All the bad guys have to do is cut 1 camera, the cutters will short out the system and your PC and camera will have a re-boot

 

z

[BigBen 0]

I've heard of people doing this to power routers placed near rooftops. The advantage is using a pair in the Cat cable to power the router. Yes, a short or spike in the remote 12v will return to the PC. Vice versa as well. You would need to protect the computer (and now camera) with a UPS preferably and protect the camera from destroying the computer's power supply (and potentially anything on the same 12v bus) from the DC side in the event of a remote failure. Do the math for the fuse needed. Protect the camera from moisture (and not with "not a snack" silica packets!) and don't skimp on the cable installation.

 

All if of course you're wanting to do this.

[zmxtech 0]

your talking about POE which uses an injector or is powered from the POE switch.

 

UPS will make no difference a 12v short will kill the PC

 

thats why I love IP cams !

[mr.surveillance 0]

If you like your computer don't tie anything thats not in the computer to its power supply. Use an external regulated power supply preferrably with twice or better current rating of the camera load. And a suitable fuse or other overcurrent protection device.

 

As I always say:

 

"Remember: All electronic devices contain smoke and if you accidentally let it out there is no way to put it back in. If you let the smoke out you will have to replace the device."

[BigBen 0]

I was not talking about POE particularly, just rigging your own POE not using injectors. The UPS protects the computer and camera in the event of a bad AC spike, surge, etc. Because if the computer gets destroyed its likely whatever is connected will be affected also. Additionally, the in-line fuse on the 12v line can protect either device depending on which one fails. A power supply does just that -regulates and filters AC with a rectifier and produces DC power. If you know what you're doing (and hopefully make it look nice) theres no problem at all tapping your power supply for voltage. Again, "if you know what you're doing"

[zmxtech 0]

for sure

[Kiwi 0]

The 12V output in a PC is well-protected against current overloads, is well-regulated, and often has plenty of excess capacity - those items are unlikely to be issues.

 

The two risks I can see with sharing the supply are:

 

a) If the camera video is connected to a card in the computer you may create a ground loop between the video shield and the 12V return, which is grounded to the computer at one end and in many cases connected to the video shield within the camera. This may not be an issue with newer cameras that take either 12vdc or 24vac.

 

b) Any wire leaving the computer box is a potential antenna for RF noise going either in or out. A ferrite bead would take care of that however.

[osamasaadah 0]

well, i can see nothing wrong of using a computer power suppply unit, it's well protected and regulated, me myself i use it for powering the cameras i install.

[kensplace 0]

What if someone comes along and shorts out one of the cables, unless you have a fuse that blows faster than the psu itself decides there is a fault and shuts down, you have a dead system and a bunch of dead cameras.

 

Or worse, what if someone comes along and injects extra voltage into the low voltage line, instead of just a blown camera, you may end up with a blown psu, no recording, and no cameras..... At best, it would probably just shut down the psu, but you would then not be recording anything....

 

Seperate PSU means the PC does not go dead in a fault condition like that.

[osamasaadah 0]

kensplace, you are just assuming , but the psu is prottected with both of fuse and a regulater,and how can any body just switch it off while it's placed in a special control room or in the manager room?!!

[kensplace 0]

The psu may be in a restricted room, but if its powering the cameras, then its output lines are connected to the outside world (assuming the cameras are outside of the control room).

 

Unless all cables are untouchable, this exposes the psu to risk, and they are designed to shut down when the are exposed to a direct short, or on overvoltage or other fault condition.

[si_kungs 0]

for 480W power supply. the 12Vdc is 15A. the number of cameras may vary depending on the number of hardware you have installed on your computer. how many cameras have you tried yo hook up on the power supply of the computer?

[cocacola 0]

Using your pc as power supply is stupid, no good idea my cctv friend.

Ust use a power supply. I have buyed one on ebay for 90 usd, 16 channels of 12 or 24 volt. each channel protected by fuse, 15 (pep 20 amp) Amps total on 12 volt.

 

I can manual turn the volts up for each channel !

[osamasaadah 0]

cocacola... we are talking about external pc power unit supply sir, whish will cost u onley 12$

[kensplace 0]

The question was not about a external psu, it was about using the one in the pc that is the DVR..

 

Are there any problems getting a 12V lead from the PC the DVR card is installed in, and powering the cameras?

[osamasaadah 0]

yes sir but i suggested the external one as a good solution

[cocacola 0]

cocacola... we are talking about external pc power unit supply sir, whish will cost u onley 12$

And it will suck the live out your camera's ...

[atropine 0]

yes sir but i suggested the external one as a good solution

 

Computer power supplies aren't just a 12v device, they're 5v and 3.3 too. I think they have to be matched load.

 

This youtube video shows a kid using a computer PSU to power a whole load of 12v things, and at the end he mentions how he also has the 5V going to a light to stop the power supply blowing up.

 

http://youtube.com/watch?v=yd-AKVhmRPM

Edited April 25, 2008 by Guest

[rory 0]

cocacola... we are talking about external pc power unit supply sir, whish will cost u onley 12$

 

A decent one can cost alot more than that, and wont power most cameras .. properly. Might as well just use a single 2 Amp plug in power supply that costs $10 in that case - no individual isolation or fuses though, so once it goes, all go.

[kensplace 0]

PC power supplies can be ran with just a 12v load, as long as the max amp for the 12v rail is not exceeded.

 

The only other connection needed (on atx style power supplies) is the power on line, which needs to be powered to turn it on.

 

Apparently, atx supplies need a minimum of about 20w load for best regulation to take place, but its not something I have noticed when using one on a test bench to power cams, but its something to bear in mind that the regulation may not be great if the load is not enough.

[atropine 0]

ok that's good to hear, they certainly are ecconomical for a regulated supply I have 3 just sitting there waiting to do something., really you just need to send the 12v to a fused switch board , and run the cameras from that. Should be as good as a super expensive CCTV power supply. No good for long runs ofcourse, but certainly has it's uses.