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 Post subject: Use 24VDC to run 12VDC cameras
PostPosted: Thu Jul 05, 2018 5:47 pm 
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3 years ago, a security company installed 31 cameras and two Altronix AL400ULXPD16 cabinets.
The camera's specs say they are rated at 4.5 Watt Max power consumption at 12VDC. The cameras are dual voltage 12VDC or 24VAC, HikVision model DS-2CE56D5T-AVFIR

Recently, we went to add a camera, and our electrician commented that the voltage at the camera was 26VDC and the new camera was 12VDC only.

Note my usage of DC and AC above.. there are no typo's.

We inspected both Atronix cabinets and saw that they were both set to deliver 24VDC to my cameras (16 per cabinet).
Assuming the installers simply made a mistake 3 years ago.. we powered everything off, switched the cabinets to 12VDC.
This worked for a while, then the cameras (which at max load will pull 6 amps) appear to have overloaded the power supply and it shut off its output power automatically.

We powered it all off again, switched the Altronix back to its 24VDC setting and the cameras are all working again just fine (including that new 12VDC only camera).

I spoke to Altronix about this and they recommended a larger power supply. They could not explain why the setting of 24VDC was not frying my cameras.
I also spoke to HikVision, and they also said that connecting the cameras to a 24VDC power would damage them.

The cable lengths from the Altronix to the cameras ranges from 20 feet to 500 feet. Most are approx 150 feet.

So.. 3 years have passed.. the cameras are working.. no indication of issues and we have confirmed that we are getting approx 24VDC power at the cameras.

The questions I would love to understand are;
1. How is it possible that we have not had any camera issues by powering them with 24VDC?

2. By spec, the 16 cameras are rated at 4.5 Watt at 12VDC thus have a max cumulative draw of 6 amps. This might explain why the Altronix dropped output power when we set it to 12VDC which has a rating of 4 amp.
When setting the Altronix to 24VDC, rated at only 3 amp, the system does not overload.
So I assume that by powering the 16 cameras with double their rated voltage, the cameras are drawing much less amperage (less than 3 amp cumulative).

The mfgs say these cameras will fry at 24VDC.. but 3 years of use says that is not true. Do install companies know that cameras will handle 24VDC?
Is overpowering cameras to reduce amp draw a common installation procedure?


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 Post subject: Re: Use 24VDC to run 12VDC cameras
PostPosted: Mon Jul 16, 2018 11:34 pm 
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Hi!
I'd say that they were running fine with 24V due the voltage drop at the long cables. With, off course, less power@higher voltages the supply had obviously no problem.
But you would have to look at the cam's power electronic part, to become more clear.
My experience is also, that most 12V rated cams work with volatages from ~9V to 25V without any issue as long as it's not too hot at their installation place.

What I still don't get, why did you mention 24VAC? I do not expect, the cam will work with AC at all - they egal have no built in rectifier.
Also when I take a quick look at the AL400ULXPD16's specs, there is either 12V@4amp or 24V@3amps, but DC only.


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 Post subject: Re: Use 24VDC to run 12VDC cameras
PostPosted: Wed Jul 18, 2018 10:24 am 
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The Hikvision DS-2CE56D5T-AVIR are dual voltage cameras. They will run on 12VDC or 24VAC. This dual voltage config appears to be common for analog cameras. This was the only reason I mentioned 24 VAC.

You are correct... the power supply is DC only.

Some of my longer cable runs probably had a small voltage drop, but I measured voltage at one camera (approx. 25ft run) and it was at 24VDC.

Hikvision said 24VDC would fry the camera.. well obviously it has not so I would say you are correct that a typical range can go as high as 25VDC.

So I guess it is just dumb luck that my cameras have not had any problems by being overpowered with 24VDC. The good news is that the security company looked at all this and replaced my power supplies with ones that would support the cameras at 12VDC.


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