Electronic Alarms and Home Security Devices - surveillance camera power draw

I'm a little confused about something and I need some advice.

I bought a surveillance camera for my house, and I want to do power over ethernet with it. The label on the camera says it uses 12v @1.5A, which calculates out to 18 watts. However, the spec sheet for the camera says that the power consumption is 9 watts maximum.

The power supply adapter that came with it is rated for 12V, 1.5A., which is 18 watts, twice as much as needed, according to the spec sheet.

Does this make sense to anyone else?

Normally, this wouldn't matter but here's what I am thinking. I actually have two of these cameras. One is already installed, and it would be a lot simpler if I could just tap off of the existing power adapter for the second camera that I want to install. But, I'm not sure about these numbers, and I don't want to risk damaging them.

So,, what do you guys think? Is this something that would be doable?

If anyone is interested the camera specs can be found here:
TRENDnet | Downloads | Internet Camera | TV-IP410 (http://www.trendnet.com/downloads/list_subcategory.asp?SUBTYPE_ID=1254)

Thanks...Randy

Generally it is never good to run a device at 100% of it's rating on a continous basis. However, you could test the cameras draw as what was listed was it's Max. (they almost always draw less) and the transformer will have been rated at it's minimum output capability. May give you some margin. How long is your run and will there be a voltage drop?

Bud

Standard electrical design principals are to design about 20% excess capacity, above load, in general; and for something that's going to be fed over long lengths of small gauge wire, you put in at least another 20%.

Since they are likely going with off the shelf transformers for this thing, an 18W "wall wart" is fairly reasonable as a choice.

Sorry guys...I got myself a little confused in my original post when I said I wanted to use the POE. That's what I was thinking about doing with the second camera until I thought about using the existing adapter.

The existing camera is only about 6' from the power adapter. The second camera would only be about another 8 to 10' away from that.

Could this setup do any damage to the camera, or would it most likely just prematurely burn out the adapter?

Thanks.

You _should_ be ok to power 2 cameras off of the same power supply. The worst that will happen will be for the transformer to fail earlier than expected lifespan.

What I thought.

Thanks for the help.

Just a few ideas. If you are connecting the device to a PC you have 12v's available from the PC. "IF" you are not overloading your 12v rail you. A good power supply should provide well over 200amps on the 12v rail.

Also the more you push your PC power supply the more efficient they are. Provided you don't hurt it. It is a good idea to NOT have a power supply that goes way over your needs as you will waste energy. If your PC needs only 150watts and you have a 300watt power supply that is 80% efficient you should have plenty of power available and it "should" be more efficient that running a wall wart.

The elimination of wall warts and the huge loss of power from a normal ATX power supply is one of the reasons I went all DC power for my home automation project.

You can read more about that project here (http://forum.doityourself.com/electronic-alarms-home-security-devices/388412-ademco-honeywell-vista-alarm-computer-interface-home-automation.html#post1561065)

I have 2 camera's with like 30+IR LED running and at one point before I added the VICOR's and the M4-ITX power supplies I was powering them directly from my ATX PC power supply.

The only thing you need to watch for is if your 12v rail voltage drops below spec. In most cases they say 5% so it should not drop below 11.6 be warned a low 12v rail can damage stuff so just make sure you measure everything.

Re
Sean M

What I thought.

Thanks for the help.