12V power over a 250' Run

[dickday 0]

I am about to install a Zmodo Z2213GY PTZ camera. I was hoping to use good quality baluns to provide power and video through a single Cat-5 cable. The distance from DVR to camera is just under 250'.

 

I spoke with a support person at Zmodo and was told not to use this, as the 5amp power adapter "must" be at the camera. There was not much good said about the use of baluns. In a perfect world I would have 110 at every fence post over-looking the horse corral, but...

 

I was told that the voltage drop would be too much over this distance.

 

Are there different grades of baluns?

 

Any thoughts or ideas would be greatly appreciated.

 

Thanks

[Owain 0]

The baluns make no difference to the power, which is just a straight through connection.

 

Voltage drop is dependent on the current, for the same power to reduce the current you will need to increase the voltage, so you could use a 50V telecom power supply and a DC-DC converter at the camera end to get back to 12V. Or use IP camera with power-over-IP which also uses a higher voltage than 12V. Or use heavier cable for the power. 2 x Cat5 would give you 7 pairs for power and 1 pair video.

[the toss 0]

While the solution that Owain has given you is fine in theory ( & quite workable for a fixed current) you will have the problem of two different current demands. There will be the standard operating current & then there will be the current under ptz operating conditions. The second will cause a greater voltage drop than the first due to increased current requirements. In these conditions the "overhead" voltage from your supply will be quite a balancing act & may not be possible.

[survtech 0]

I agree with the toss but would also add that the IR LEDs also are probably not "On" during the daylight so now you have two variables that will affect the voltage drop: motor current draw during pan/tilt operations and LED current draw at night.

 

Although Zmodo's specs are unclear on this, I would guess that quiescent power requirements (daytime, no movement) would be under 1 amp while nighttime movement would draw up to 5 amps. Therein lies your problem. If you kick up the supply voltage to account for the voltage drop at 5 amps, you will likely fry the camera during daytime no load conditions and if you keep the supply voltage low enough during daytime no-movement to prevent over-voltage, the voltage at night under movement would be too low to power the camera.

 

One way around the problem would be to use a heavy gauge power wire but even 12 gauge wire would drop 4 volts over 250 feet at 5 amps. 12 gauge wire is 0.1588 ohms per 100 feet and both positive and negative wires of the pair would have an equal drop so .1588 x 2.5 x 2 = .794 ohms x 5 Amps = 3.97 volts drop across the power cable under full load. 10 gauge wire would have a resistance of .25 ohms per 250 feet (.5 ohms total), which would drop the voltage 2 volts at 5A vs. 0.5V at 1A. That might be sufficient, depending on the voltage tolerance of the PTZ, but it's still a 12.5% swing. Wire thicker than 10 gauge would solve the problem but is very difficult to find.

 

You're best to power the camera from a nearby source or consider a 24VAC PTZ or one without IR (which probably takes the majority of the power). A Pelco Spectra IV, for example, only uses ~ 1 Amp max without heater/blower at 24VAC. 250 feet would be a breeze with 18 gauge, or perhaps 14 gauge with heater.

[shockwave199 0]

If you have the camera and must install it, maybe you could run an extension cord to get power closer to the camera- if not right to it. It would be a drag to do and would require a weather tight enclosure for the power adapter out there- if it is in fact exterior. But if you have an outlet and you run an extension cord, it could be way to get the adapter closer to the camera. Maybe?

[ssnapier 0]

Just as a rule of thumb, I never run DC voltage more than 30 feet.

[shockwave199 0]

I was kind of faced with the same problem with my ptz, only not as extreme. From the power source by the dvr to the ptz it's 100'. I decided to power the camera from an outlet in the attic at 40'. Haven't had a problem, and glad I did.

[Owain 0]

If you kick up the supply voltage to account for the voltage drop at 5 amps, you will likely fry the camera during daytime no load conditions and if you keep the supply voltage low enough during daytime no-movement to prevent over-voltage, the voltage at night under movement would be too low to power the camera.

 

Not if the supply is (a) adequate, and (b) regulated. Note I specified a voltage converter at the camera end; the camera is not being supplied directly by the line voltage. Higher line voltage reduces the current, so reducing voltage drop, and regulating at the camera prevents any fluctuation in line voltage affecting the camera.

[survtech 0]

If you kick up the supply voltage to account for the voltage drop at 5 amps, you will likely fry the camera during daytime no load conditions and if you keep the supply voltage low enough during daytime no-movement to prevent over-voltage, the voltage at night under movement would be too low to power the camera.

 

Not if the supply is (a) adequate, and (b) regulated. Note I specified a voltage converter at the camera end; the camera is not being supplied directly by the line voltage. Higher line voltage reduces the current, so reducing voltage drop, and regulating at the camera prevents any fluctuation in line voltage affecting the camera.

So, you're suggesting feeding 50 Volts and regulating that to 12 Volts at the camera end? First, that "fix" goes beyond Class 2, which is limited to 24 Volts, so theoretically it requires an electrician to wire (almost as flaky an idea as running an extension cord to the camera). Second, 50 Volt power supplies are not that easy to find, nor are suitable DC-to-DC converters. And forget any other kind than switching. Non-switching voltage regulators dissipate the voltage drop as heat. Even assuming a 20 Volt loss in the cable, you still have to dissipate 28 Volts times 4 Amps (approximate) or over 100 Watts.

[Owain 0]

So, you're suggesting feeding 50 Volts and regulating that to 12 Volts at the camera end? First, that "fix" goes beyond Class 2, which is limited to 24 Volts, so theoretically it requires an electrician to wire (almost as flaky an idea as running an extension cord to the camera). Second, 50 Volt power supplies are not that easy to find, nor are suitable DC-to-DC converters. And forget any other kind than switching.

 

Yes. 48V / 50V is only the same voltage as telephone lines, and lower than some PoE implementations.

 

Took me about two minutes to find a nice selection on ebay.com eg

http://www.ebay.com/itm/110960049789

http://www.ebay.com/itm/300452160874

 

DC-DC converters about £10 each if you go to Ebay China. Twenty bucks US.

http://www.ebay.com/itm/261147745875

 

If the cameras are in clusters, one per camera might not be needed.

 

You're right, it would be switched mode converters. I wasn't thinking of dropper resistors.

[dickday 0]

Will someone explain where and when you could use baluns with Cat-5 when installing cctv cameras (or point me to a site that does explain it)? In watching some YouTube videos, I got the impression that the use of baluns were fairly common in professional installations. Again, I am dumber than a rock when it comes to this, so excuse the ignorance.

 

So far I haven't heard anyone say anything bad about using baluns for video and ptz control, just power.

 

Thanks again.

[the toss 0]

Baluns are simply BALanced to UNbalanced impedance matching transformers that matches a 75^ camera O/P to a 100^ transmission line (Cat 5/6 ) & then back to a 75^ I/P at the DVR. By using a balanced transmission line you get all sorts of noise rejecting properties which may or may not be of benefit. Some people swear by the use of Cat 5/6 while others prefer to stick with RG59. Keep in mind that while Cat 5/6 has a lower loss /m than RG59 the simple use of baluns will itself result in an insertion loss depending on the quality of the balun.

My biggest problem with baluns it the physical fragility of the terminations. Have a look behind some 16 ch DVR installs & it is a nightmare. Imagine instead of robust RG59 & BNC connectors , the terminations in that mess were a pair of cat 5?6 wires on a screw or insert connection. The ONLY time I use Cat 5/6 is when it can be terminated at a patch panel & RG59 patch leads can be used.

[shockwave199 0]

almost as flaky an idea as running an extension cord to the camera

Yeah okay- flaky I admit.

 

So far I haven't heard anyone say anything bad about using baluns for video and ptz control, just power

That's because if you can't solve the power issue, you're sunk and you can forget about anything further for your ptz.

 

The distance from DVR to camera is just under 250'. I spoke with a support person at Zmodo and was told not to use this, as the 5amp power adapter "must" be at the camera. There was not much good said about the use of baluns. In a perfect world I would have 110 at every fence post over-looking the horse corral, but...

 

I was told that the voltage drop would be too much over this distance.

[survtech 0]

I wasn't thinking of dropper resistors.

Even so-called voltage regulators, such as the 7812, are basically resistive and would have to dissipate a huge amount of power.

[dickday 0]

I really appreciate the comments and suggestions. It's too late to return the camera, so I have to make the best of what I have.

 

Until spring when the ground thaws, and can run conduit out to the site, I'll run heavy extension cords there and install the 12V power supply in the 10"x10" sealed junction box I installed on the post. The power supply is rated at 5amps. It looks like I'll need about 150' of extension cord to get to that post. If I use fairly heavy cords, do I have to worry about AC voltage drop on that small of a load?

 

For future use, how far can you safely use Cat5 and power baluns before you have enough voltage drop to be a problem when running to a fixed (no ptz, no heaters or fans) camera?

 

Thanks again.

[ssnapier 0]

I really appreciate the comments and suggestions. It's too late to return the camera, so I have to make the best of what I have.

 

Until spring when the ground thaws, and can run conduit out to the site, I'll run heavy extension cords there and install the 12V power supply in the 10"x10" sealed junction box I installed on the post. The power supply is rated at 5amps. It looks like I'll need about 150' of extension cord to get to that post. If I use fairly heavy cords, do I have to worry about AC voltage drop on that small of a load?

 

For future use, how far can you safely use Cat5 and power baluns before you have enough voltage drop to be a problem when running to a fixed (no ptz, no heaters or fans) camera?

 

Thanks again.

 

 

When you say heavy extension cords, please make sure you have actual larger wires and not just thick insulation. I would use no small than 12AWG cord if it were stuck in that position, but I might even make one out of direct burial 10AWG wire with good quality weather proof plugs on each end. Oh and PLEASE make sure you are using GFCI!

[dickday 0]

That's an excellent idea, thank you. If I am going to invest in really heavy-duty extension cords as a temporary fix, it would make sense to buy enough of the direct bury cable, put ends on it, and then in the spring, use that same cable to create a permanent run.

 

The outlet that I would temporarily plug into is a GFCI. I would also have our electrician fabricate the cable for me and then come back later and use the same cable when he installs the circuit on the pole. I know my limitations and I would feel safer not doing this myself. (funny, as I get older, the fewer things I feel comfortable doing... maybe 50 years ago I would have tried it

 

Do you have any thoughts on how far I could send 12 volts over Cat 5 using baluns before voltage drop would be a problem? Could I combine a pair in the Cat5 as one half of the 12-volt feed? Would that help reduce the loss? The cameras I would be using are the Zmodo CM-S22326BG-AD

 

http://www.zmodo.com/security-cameras/ir-night-vision-camera.html

 

The reason for the interest using Cat5 is that when I installed our 16-camera system last year, I used the closest length of video/power cables I could find that would reach the dvr. Many of the cables are anywhere from 10 to 30 feet too long and are sitting under the dvr. I would like to be able to re-wire those cameras with cat5 and terminate the ends at a patch panel and get ride of the cable mess sitting at the dvr. I had looked at running coax but was told that I would still have to run additional cable for power.

 

Again, thank you.

[dcrow57 0]

I'm no expert, but I can tell you I also have a CM-Z2213GY, its powereed with the power supply it came with through the cheapest baluns I could find and 100 feet of Cat 5e plus a 10 foot cat 5 patch cord, and it works fine, no problems.