slovey

The answer to your question is to power the camera locally , calculating cable length and voltage drop to overvolt from source is not a good idea, if you calculate to get 12v to camera when the IR is on , you are gonna get more voltage when the IR is off.Measuring the cable will not give you a true idea , you need to know what the current the camera is drawing as well as voltage.

Thanks for the suggestion, but that wasn't possible. The full solution I used is posted, but the gist of it is I used a 24v power supply with a 12v adapter at the camera. It works great and the camera is getting right at 12v, even with a 4v drop.

Solution:

I used a 24vac 40VA power supply with a 24vac to 12vdc adapter at the camera.

Notes: I found some ac/dc adapters/converters that had an input voltage range of 20-24v (common) and some that had an input range of 16-28v (harder to find). As long as you are getting at least 20v at the camera, it shouldn't matter which you use. If you are getting less than 20v, you may need the adapter with the lower input range.

40VA roughly translates into @1.6amps DC. You may be able to use a 20VA or 30VA power supply if you need less amperage for your cameras - there are online conversions from VAC to VDC that can help you decide which power supply you need.

The voltage drop calculator is not even close to matching my real world situation.

For example, I have the following:

12v DC power supply (18 ch./1.6amp per channel)

Camera draw @700-1000mA

Cable run of 600ft

18 gauge cable (stranded)

According to the SuperCircuits voltage calculator, I should have a drop in voltage of 5.38v (minimum draw - 700mA), which would leave only 6.62v, and shouldn't power this camera. But, it is working fine. And, the measured voltage under load is 8.9v. I understand that there are real world factors that can't be applied with a voltage calculator, and the power supply is actually putting out 12.7v rather than 12v, but a difference of 2.28v seems extreme. Am I missing something?

Also, would it be possible to use a 24vac power supply with a 24vac to 12dc converter at the camera?

Here is another solution - solar panels with a charger for the backup batteries!

Thanks for the suggestion.

I don't think I would be able to power the cameras where I live due to the number of consecutive overcast days we have and the inability to get direct sunlight - may require a very large battery. And, I already have the cable in place for traditional power.

I do really like the idea of solar power though and I would have liked to set it up that way.

12v to 20v 5amp power supply will do your job

 

Just turn up voltage till you have 12v at camera

Thank you for the help.

Where can I find a 5amp power supply with a variable adjustable voltage of 12-20v?

Through searching I was able to find a power supply that had 12-13.8 volts, but I couldn't find anything that was 12-20v.

I have NOT said to disconnect the camera. The voltage reading must be done at the camera while it is connected & the IR is on. You should be able to buy a cheap multimeter for less than $20.

A simple calculation using 12Vdc as your power supply , 460 mA as the current drain and 700' of 18 awg as your cable gives a voltage drop of 4.12V meaning load voltage is 7.88V. This is way below what you would expect the camera to run on.

 

I have a multimeter, but I don't see how to use it if the contacts are not exposed while the cameras are connected. The real question is what is the solution. How do I get enough power to the cameras??

 

The REAL question is - do you want to understand your problem or do you just want somebody else to solve it for you? Given that the voltage drop is 4.12 volts (for the parameters you have given) then getting a power supply that provides 4.12 volts ABOVE the nominal 12V required by the camera will offset that voltage drop. So a 16Vdc power supply will solve your problem -for the specific camera in question

The REAL answer is - I came here for help, NOT looking for a condescending jerk to give me attitude.

I do NOT need to understand all or any of the math/physics/science behind the solutions for any answer I seek on the internet. And, if you believe that all the people looking for answers in forums want to be taught, or want to be shown how to solve the equations themselves, you are delusional. I do like to learn new things, but I want to be the one to decide what I want to learn, and in this case I am in a time crunch.

I am here for an answer to my problem. Low voltage wiring is not my specialty, and I came here for answers...for solutions. However, I have understood from the very beginning that there was a voltage drop, and I provided all of the specs I had so it would help someone who knew what they were doing give me a solution to my problem. Just like if I can help someone on Quora with info I have, I will. I don't require them to learn why the solution works.

I am sure I will have more issues with this install seeing how I am an under-qualified novice (tried paying a couple of installers originally, but I had such bad experiences I gave up looking and did it myself). However, I doubt I will look for answers here again since they can be dispensed so begrudgingly.

I have NOT said to disconnect the camera. The voltage reading must be done at the camera while it is connected & the IR is on. You should be able to buy a cheap multimeter for less than $20.

A simple calculation using 12Vdc as your power supply , 460 mA as the current drain and 700' of 18 awg as your cable gives a voltage drop of 4.12V meaning load voltage is 7.88V. This is way below what you would expect the camera to run on.

I have a multimeter, but I don't see how to use it if the contacts are not exposed while the cameras are connected. The real question is what is the solution. How do I get enough power to the cameras??

You need to measure the voltage AT THE CAMERA at night with the IR operating. That will give you a clue as to what is going on.

Is there any truth to this??

" The Voltmeter has a very low amp draw, and will show less voltage drop because of that. Once the camera is reintroduced in the circuit, the voltage drop will change, making the measurement ineffective."

You need to measure the voltage AT THE CAMERA at night with the IR operating. That will give you a clue as to what is going on.

Also, I don't have anything to test the voltage on the DC connector. Is there some cheap,reliable device that does just that?

You need to measure the voltage AT THE CAMERA at night with the IR operating. That will give you a clue as to what is going on.

I already know there is a voltage drop. How do I fix it? I don't have any power source any closer and I don't want to run thicker gauge cable for that distance. So, is there a way for me to boost the power within my current setup?

Specs:

-rg6 siamese direct burial cable runs (18 gauge) of 215 meters (@700 ft)

-HDCVI cameras that pull 5.5 watts or less (460 mA by my calculations)

-12v DC 29amp 18 channel power supply

Problem:

-all cameras have power, but losing image at night when the IRs turn on

Question:

How can I boost the power? Some type of amp or power booster?

Or, should I increase the amperage at the power supply?

The light off means NO power is being supplied to that output. This will be due to a current overload triggering the electronic fuse (PTC). Disconnect the camera on that feed but leave the cable connected to the power output at the power supply. If the light still goes out then you have a short on the cable to the camera. If it doesn't go out then you have a fault in the camera itself

Thanks for the help. I already tried swapping out the camera with one I know works and I replaced all the connectors (which didn't solve the problem), so it must be a short in the cable itself. The current cable is rg59 siamese direct burial (18/2 for power) and for there to be a short in the cable would mean that the cable came faulty from the manufacturer, which seems hard to believe, but possible.

The cable run is 125 meters and I assume the only solution is to run another power cable just for that camera all the way back to the power supply (there isn't any power source closer).

I have an 18 channel power supply box installed and each channel has a camera wired to it. All channels have an led light in the box next to the terminals and that light is on on all but one channel. On the channel with the light out, I have no image on the monitor. If I disconnect the camera power cable from that terminal, or connect a different camera to that terminal, the light comes back on - it is only off when the power cable from that specific camera is connected to any terminal.

Does the light out on a power supply box with a camera wired to it mean the the circuit is not being completed? Or, more broadly, what are the possible indications for the light to be off?

All of the installs are outdoors far away from any buildings or overhangs - the cameras are to be used to monitor the streets of the property. The cameras are very spread out and there will be a box at every camera location with either one, two or three cameras sharing the box. I know the importance of a drip loop and I have allowed plenty of extra cable for the loops.

I have looked for the Gewiss-type boxes at local box stores (Home Depot and Lowes) and the local supply houses (Grainger, Graybar, etc) and online, and I haven't found anything for less than $40/box - most were WAY more than that. The Carlon boxes (E987R) are easily found for around $11 dollars locally, but that is a different style of box - it is screw down on all four corners instead of hinge open, it is a basic, empty box with no knockouts or pre-manufacturered contact bar mounting holes inside, and the seal seems to be more of a permanent, putty-type seal. I would prefer to use the Gewiss-style box, but it seems like I am going to have to go the Carlon (basic weatherproof junction box) route at this point.

Numb-nuts,

Thanks. Those are exactly what I was looking for - boxes and glands. Unfortuately, I can't find Gewiss in the States. The prices were very reasonable. I found similar junction boxes, but they were usually way over-priced.

If anyone can suggest a place to get good boxes like that for reasonable prices (in the US) I would appreciate it.

I am completing the installation of a CCTV System with 40 cameras (HD-CVI). It is in a mobile home park with aerial runs up to 250 meters (rg59 siamese direct burial). Most of the camera locations (27) have either one or two cameras. I am trying to decide how to make the camera connections (BNC and 18/2).

My plan has been to use some type of weatherproof/waterproof junction box to make the connections, but I haven't been able to find a box that has grommet holes or sealed popouts. I am hoping someone can point me in the direction of a suitable box, or a feasible way to modify some stock junction box. If the box had a connector strip for the power connections, that would be even better.

I am also interested in suggestions for how best to make the power connections from the unterminated cable to the power adapter plugs (wire nuts, screw-type terminations). Since some of the runs are fairly long, I am looking for connections that don't degrade the power.

Any photos of connections made at camera locations would be very helpful.

Does anyone know of a reliable video test monitor for HDCVI? Or, of a converter from HDCVI to NTSC/PAL so that an analog monitor can be used?

There are other issues to consider such as the quality and type of cable. The rg59 might have been a much better cable in most or all of those situations. I don't know how many anecdotal examples you have, but maybe the rg6 cable was copper clad aluminum (CCA). I have read that hdcvi video starts to degrade pretty rapidly over aluminum. I know there are far fewer choices of rg6 than rg59 cable available and it is possible that those installs were done with inferior cable, though less likely if you have a lot of examples.

I am installing an HD-CVI 960p system on my property (business) and I have cable runs that go up to 200 meters. I want to know if I can get by using rg59 (solid copper, high quality, direct burial - something I already have) or if I will be better served by rg6 (same quality as rg59).

Essentially, I am asking if I stand to gain anything in the way of image quality by using rg6 at that distance. OR, at what distance would rg6 make a difference in image quality - assuming all cables are high quality, solid copper?