12v over Ethernet instead of 48v for uniview camera
- Thread starter sharkam52
- Start date
Thank you so much for the quick response !
I was just wondering if the camera takes direct 12v input why wouldn't it work with 12v over the Ethernet as the voltage at the camera will be very close to 12v and this makes it easier to use a 12v UPS with it.
Thanks again for your response.
I was just wondering if the camera takes direct 12v input why wouldn't it work with 12v over the Ethernet as the voltage at the camera will be very close to 12v and this makes it easier to use a 12v UPS with it.
Thanks again for your response.
fenderman
Staff member
- Mar 9, 2014
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The voltage would drop by the time it reaches the camera. You would need to use passive splitters on both ends which is a mess....no need for a silly 12v ups...
Thanks fenderman for your response.
But where I live we have regular power cutouts.
Sometimes there is no power for hours so using a dc ups greatly extends the camera uptime.
Edit:and I think the voltage drop will be very minimal.
However,you gave me a very good idea (using splitters on both ends). Does this work ?
But where I live we have regular power cutouts.
Sometimes there is no power for hours so using a dc ups greatly extends the camera uptime.
Edit:and I think the voltage drop will be very minimal.
However,you gave me a very good idea (using splitters on both ends). Does this work ?
Last edited:
fenderman
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no it does not work well. You do know that they sell standard regular UPS's for your 230v. But you seem to know better, so screw around with this backwards setup, then create a post complaining that your camera freezes, drops offline etc..
thank you for your continued assistance fenderman.
You are right about the regular ups’s but the problems with them are the size,cost and efficiency.
They are more than 10 times larger than the 12v ups’s but they are much less efficient,especially at these low voltages.
However I will take your advice and avoid the splitters and will try to look for 48v ups’s.
There are 24v ups’s mainly for wireless networks but I haven’t seen 48v ones.
Again thank you for your assistance,much appreciated.
You are right about the regular ups’s but the problems with them are the size,cost and efficiency.
They are more than 10 times larger than the 12v ups’s but they are much less efficient,especially at these low voltages.
However I will take your advice and avoid the splitters and will try to look for 48v ups’s.
There are 24v ups’s mainly for wireless networks but I haven’t seen 48v ones.
Again thank you for your assistance,much appreciated.
fenderman
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you are confused, you dont need a 48v ups...you need the SAME type of ups you would use for your computer or NVR.
I bought only the camera which didn’t come with a power supply,and I have a passive Poe injector that I want to use with the camera with a 48v power source.
And I don’t have an NVR,I intend to connect the camera with my WiFi router and use it from my phone.
I don’t intend to record the video and all my network have their continuous power sources(they all work on 5v)
So only the camera needs a continuous power source.
And I don’t have an NVR,I intend to connect the camera with my WiFi router and use it from my phone.
I don’t intend to record the video and all my network have their continuous power sources(they all work on 5v)
So only the camera needs a continuous power source.
fenderman
Staff member
- Mar 9, 2014
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buy an 802 poe switch they are cheap. start reading about how poe works, you are confused.
Thanks again for your response.
As I understand the 802.3af standard delivers 48v to the camera.
So wouldn’t a passive poe injector with a 48v power supply deliver the same power ?
Please correct me if I am wrong in this assumption.
As I understand the 802.3af standard delivers 48v to the camera.
So wouldn’t a passive poe injector with a 48v power supply deliver the same power ?
Please correct me if I am wrong in this assumption.
fenderman
Staff member
- Mar 9, 2014
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There are passive midspans and injectors, you dont explain what you are using and what you are trying to do...just get an active poe injector and forget about this crap...nice, clean, reliable.
I am just using a simple passive Poe injector like this one:
Google Image Result for https://compratecno.cl/image/cache/catalog/NETWORKING/ACCESORIOS/0018-ACCESORIOS-MIKROTIK-RBGPOE-COMPRATECNO-1-726x1000.png
If I use it with a 48v power supply would it work?
Anyway I will do more research about this.
Thanks again for your assistance!
fenderman
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The thing you have to realize is that to use the 48V that you get from a "normal" POE system, the cameras incorporate a DC-DC converter to step the 48V down to whatever the camera really wants to run off of. That might be 12V, since the camera has a 12V connection as well. When you power the camera over the ethernet cable, the wire is quite small. So using a higher voltage to carry the power through those thin conductors makes sense because you don't have anywhere near as much voltage drop in the wiring. It's the same reason that long high-power transmission lines operate at very high voltages (so-called high "tension" wires).
If you want to run and back-up the camera from a 12VDC system, you can always just wire that 12V power into the camera's 12V power jack and not use POE at all. POE is great for when you don't want to run a separate power cable and use a separate power supply for the camera.
But if you're going to end up kludging in some sort of non-standard power into the ethernet cabling, it will likely be a lot more trouble than it's worth.
As fenderman has said, just get a normal POE injector and then use a normal UPS to power the injector.
I understand what you're saying about how multi-conversion UPSs are inefficient, large, expensive, etc. But they do serve a purpose. You could power your PC or NVR as well as a POE switch (or power injector) all from the same UPS, and solve all of those problems at once. To make the system work, more than just the camera will need to be battery-backed, if I understand your setup.
Building or buying a 48V DC UPS seems like more money and trouble than just buying a typical UPS that provides the usual mains power for your area (120VAC here in the US).
If you want to run and back-up the camera from a 12VDC system, you can always just wire that 12V power into the camera's 12V power jack and not use POE at all. POE is great for when you don't want to run a separate power cable and use a separate power supply for the camera.
But if you're going to end up kludging in some sort of non-standard power into the ethernet cabling, it will likely be a lot more trouble than it's worth.
As fenderman has said, just get a normal POE injector and then use a normal UPS to power the injector.
I understand what you're saying about how multi-conversion UPSs are inefficient, large, expensive, etc. But they do serve a purpose. You could power your PC or NVR as well as a POE switch (or power injector) all from the same UPS, and solve all of those problems at once. To make the system work, more than just the camera will need to be battery-backed, if I understand your setup.
Building or buying a 48V DC UPS seems like more money and trouble than just buying a typical UPS that provides the usual mains power for your area (120VAC here in the US).
Thank you J Sigmo for the detailed answer! I didn’t know about the voltage step down at the camera.
And yes in my setup only the camera needs to be battery-backed, all my network(which is very simple) is already battery-backed,there is no pc or nvr.
And we have very cheap 24v ups’s here. The problem is finding 48v ones.
And yes in my setup only the camera needs to be battery-backed, all my network(which is very simple) is already battery-backed,there is no pc or nvr.
And we have very cheap 24v ups’s here. The problem is finding 48v ones.
What is the difference between passive and active Poe if you supply the same voltage ?
looney2ns
IPCT Contributor
Thanks looney2ns for the article.
What I understood from it is that with passive Poe you need to know what voltage is required by the device and supply that exact voltage.
Anyway I am now using a 10m extension cable for the 12v input and will see what I will do next.
Thanks everyone for your assistance!
What I understood from it is that with passive Poe you need to know what voltage is required by the device and supply that exact voltage.
Anyway I am now using a 10m extension cable for the 12v input and will see what I will do next.
Thanks everyone for your assistance!
tangent
IPCT Contributor
- May 12, 2016
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I'm not overly fond of calling it active poe.
Standard compliant PoE is based on standards like 802.3af or 802.3at (there are a couple new/upcoming standards too). The biggest difference compared to passive PoE is that the device that wants power negotiates for it. It effectively says hey I want power and need this much and the switch (power sourcing equipment) say ok if the powered device asks properly and the PSE can supply the amount of power requested.
This is an over simplification, but the bottom like is Passive PoE lacks the protection schemes that are part of various standards and help protect your devices.