No voltage drop 12v over 1000'?

[mshaffer 0]

I'm setting up an analog camera 2000ft from my house and I was going to power it with a solar panel near the camera. I just got the cable though and did a voltage test and it reads 12v through the entire 1000ft spool, using just two of the 24g conductors. So why can't I just run power from my house? For some reason I thought 12v would only go a few hundred feet or something.

[mshaffer 0]

Is it because there is no amp load from the multimeter? I used the voltage calculator and it shows more of a drop in voltage.

[survtech 0]

Voltage on cable only drops when a load is attached. A multimeter is typically almost no load at all due to its very high resistance. Attach a camera to the end and you will likely see the voltage drop considerably.

[Mat 0]

or you could just use a 24vdc power supply instead for a 2000' 24awg run. Not sure what you video is gonna look like though...

[hardwired 0]

If it is just a standard (non-PTZ) analog camera, you could use three of the pairs for power, and one for video, which would help with the drop. Also, you may want to put your meter inline with a 12 volt supply and the camera (on the DC 500ma setting), to measure the actual current draw (if the camera has IR illumination, cover it to turn the IR on, it will draw more current that way).

 

Another consideration is to use a higher voltage supply (24VAC or so), with a regulator at the camera to drop it back to standard 12VDC power. This model from Altronix is good up to one amp supply current-http://www.altronix.com/products/product.php?name=VR1T

[dalepres 0]

If it is just a standard (non-PTZ) analog camera, you could use three of the pairs for power, and one for video, which would help with the drop. Also, you may want to put your meter inline with a 12 volt supply and the camera (on the DC 500ma setting), to measure the actual current draw (if the camera has IR illumination, cover it to turn the IR on, it will draw more current that way).

 

Another consideration is to use a higher voltage supply (24VAC or so), with a regulator at the camera to drop it back to standard 12VDC power. This model from Altronix is good up to one amp supply current-http://www.altronix.com/products/product.php?name=VR1T

 

I know this is an old thread but since there's so little activity on this forum and I think it could be important for future readers of this thread, I'm going to reply and hope no one objects too loudly.

 

The reason POE systems use 48 volts is to reduce the current, and thus the loss, on the 23 to 24 gauge Ethernet cables. Same principle in power distribution. Power form the plant comes out often at over a hundred thousand volts so that the power lines to your neighborhood don't have to be 4 inch copper or bigger.

 

So the solution to power 1000 feet away is to use high voltage and lower current. My suggestion is to feed with a 48v supply and in a burial junction box with a 12v regulator - buried to help keep the box cool.