Power for cameras on light poles

[wirebender]

A customer (automobile dealerships) is installing surveillance cameras on light poles.

We are installing weather proof boxes up high on the pole (maybe 20 feet) and putting receptacles inside for them to plug in their power supply. We have come to some locations that would be difficult at best to get constant 120V power and I am looking for options. Some poles are 120 some 208 and some 277.

One option is to let the cameras run off battery during the day and charge at night while the lights are burning. Maybe some kind of UPS?

Another is they possibly could do without the cameras during the day and just use the power that is operating the light. If we go this route, what type of transformers would we need to use?

The cameras use about 15 watts.

Anyone have any experience in this or suggestions?

 

[charlie b]

I would not rely on the battery. My suggestion is to look for the type of camera that gets its power from the data cable. I think it is called "power over ethernet," or something to that effect. You are going to have to run a data cable to each camera anyway, so why go through the trouble of adding a separate power cable?

 

[zbang]

Definitely use PoE cameras for this, it'll make life so much easier.

 

[wirebender]

I would not rely on the battery. My suggestion is to look for the type of camera that gets its power from the data cable. I think it is called "power over ethernet," or something to that effect. You are going to have to run a data cable to each camera anyway, so why go through the trouble of adding a separate power cable?

No cables to the cameras, wireless.

Only thing required is a power supply.

 

[gar]

131016-1932 EDT

wirebender:

You did not mention the DC voltage required at the camera. I will assume 12 V. Thus, current equals 15/12 = 1.25 A. To run without power for 24 hours will require a battery larger than 12 V at 30 ampere-hours (half of a car battery). You can use whatever criteria you want for the time period, but you would also need to use a larger battery than the minimum AH rating.

Fundamentally the battery is not feasible.

.

 

[mgookin]

How many cameras? If it's not a lot of cameras and they are close together, consider running a dedicated branch for the cameras. If you consider the value of their inventory, it's likely a micro percentage.

 

[wirebender]

131016-1932 EDT

wirebender:

You did not mention the DC voltage required at the camera. I will assume 12 V. Thus, current equals 15/12 = 1.25 A. To run without power for 24 hours will require a battery larger than 12 V at 30 ampere-hours (half of a car battery). You can use whatever criteria you want for the time period, but you would also need to use a larger battery than the minimum AH rating.

Fundamentally the battery is not feasible.

.

12V, probably be on battery 14 hours or less.

How many cameras? If it's not a lot of cameras and they are close together, consider running a dedicated branch for the cameras. If you consider the value of their inventory, it's likely a micro percentage.

We're talking some major concrete sawing to get to these locations, or trying to re-pull circuits thru many light poles in conduits that have been in place for 20+ years.

 

[mgookin]

There are plenty of security related power supplies and even UPS systems but I don't think they're made for that much power outage every day. It seems like you're going to be adding a whole lot of equipment and adding weight on these light poles, then have to maintain batteries and chargers.

Solar systems are made for near total discharge on a daily basis. I have heard Golf Cart batteries make the best solar system batteries because they are made to be run to near zero on a daily basis.

What comes to mind is what the USCG uses for channel markers that flash at night. They have a solar system which charges all day, then powers the flashing light at night. You'll be charging at night and powering it during the day with your battery. At night you'll be still drawing from the connection to the battery but you'll be feeding that battery from the charger.

You can get charger boards from Grainger. Someone's got to come up with the design for the box (boxes) to hold all this and mount it all in a structurally sound fashion. Maybe your boxes/ batteries can be near or on grade but protected by lock & key so it's easier install work & maintenance.

 

[wirebender]

There are plenty of security related power supplies and even UPS systems but I don't think they're made for that much power outage every day. It seems like you're going to be adding a whole lot of equipment and adding weight on these light poles, then have to maintain batteries and chargers.

Solar systems are made for near total discharge on a daily basis. I have heard Golf Cart batteries make the best solar system batteries because they are made to be run to near zero on a daily basis.

What comes to mind is what the USCG uses for channel markers that flash at night. They have a solar system which charges all day, then powers the flashing light at night. You'll be charging at night and powering it during the day with your battery. At night you'll be still drawing from the connection to the battery but you'll be feeding that battery from the charger.

You can get charger boards from Grainger. Someone's got to come up with the design for the box (boxes) to hold all this and mount it all in a structurally sound fashion. Maybe your boxes/ batteries can be near or on grade but protected by lock & key so it's easier install work & maintenance.

I'm thinking the camera man has ruled out solar because of price, but it is one option.
I talked to him a while ago and he has found a UPS that he thinks will work but it's about 600 bucks, but may be the way we go if we can't solve it another way.

Thanks

 

[gar]

131016-2102 EDT

wirebender:

How much outside of the time frame when the lights are on is it necessary for the cameras to operate? Can the cameras be programmed to only transmit when there is motion? And probably for a period following loss of motion. Can overhead wires be strung between the light poles?

Is continuous motion needed or would 10 single frames per second be fast enough?

If you can not readily provide power, thus requiring some sort of battery power, then can low power motion sensors be used to determine when to activate the cameras and transmission?

You can certainly get power for battery charging from the lights when the lights are on. But you may not be dealing with a small battery. Li-ion might be useful, but high cost.

.

 

[wirebender]

131016-2102 EDT

wirebender:

How much outside of the time frame when the lights are on is it necessary for the cameras to operate? Can the cameras be programmed to only transmit when there is motion? And probably for a period following loss of motion. The ones that we are having trouble with will be monitoring the service road on the Interstate, so motion is probably not a viable option.

Can overhead wires be strung between the light poles? not an option, problem is still getting power to the area.

Is continuous motion needed or would 10 single frames per second be fast enough? I imagine this is possible and may already be the case, I'll check with the camera man

If you can not readily provide power, thus requiring some sort of battery power, then can low power motion sensors be used to determine when to activate the cameras and transmission?

You can certainly get power for battery charging from the lights when the lights are on. But you may not be dealing with a small battery. Li-ion might be useful, but high cost.

.

I'm going out of town for a few days, but should know early next week what we decide.

If they decide they only need them at night, does anyone have a recommendation for reliable transformers?

 

[__dan]

You don't want a transformer. The cameras are probably DC input, 12 or 24 volt. You want a wide voltage range, 120 to 277 volt input, switching power supply, waterproof. Meanwell is a good name, should have what you need.

 

[wirebender]

You don't want a transformer. The cameras are probably DC input, 12 or 24 volt. You want a wide voltage range, 120 to 277 volt input, switching power supply, waterproof. Meanwell is a good name, should have what you need.

Thanks

 

[wirebender]

You don't want a transformer. The cameras are probably DC input, 12 or 24 volt. You want a wide voltage range, 120 to 277 volt input, switching power supply, waterproof. Meanwell is a good name, should have what you need.

The security people came up with a UPS with a power supply PS24V-2.5 which is 100-240v input 24vdc output 2.5A, cord and plug connected.

This works fine for all but one pole which is 277V and i can't seem to find something similar in 277 volts. Most seem to go to 264V.

 

[GoldDigger]

The security people came up with a UPS with a power supply PS24V-2.5 which is 100-240v input 24vdc output 2.5A, cord and plug connected.

This works fine for all but one pole which is 277V and i can't seem to find something similar in 277 volts. Most seem to go to 264V.

If the pole is getting 277 to ground, it might be on the high leg of a center grounded delta arrangement. Either you need to get your 240 between two phase conductors or something is wrong with the wiring.
In any case, if the system is actually OK using the 277, you can just add a stepdown or buck transformer between the 277 and the DC power supply. A lot easier than finding a supply with that high an allowed input voltage, since 277 is not common.

 

[wirebender]

If the pole is getting 277 to ground, it might be on the high leg of a center grounded delta arrangement. Either you need to get your 240 between two phase conductors or something is wrong with the wiring.
In any case, if the system is actually OK using the 277, you can just add a stepdown or buck transformer between the 277 and the DC power supply. A lot easier than finding a supply with that high an allowed input voltage, since 277 is not common.

No, this pole is supposed to be 277V. This is a car dealership with many adjoining properties and different voltage systems on all of them. This one is a a 480Y/277V system.

How would I size the buck transformer?

 

[winnie]

Hmm. Rather than putting the camera systems on large batteries, what about running power to the poles continuously, and then switching the lights locally at the poles, using wireless, photocell, or a time switch?

 

[wirebender]

Hmm. Rather than putting the camera systems on large batteries, what about running power to the poles continuously, and then switching the lights locally at the poles, using wireless, photocell, or a time switch?

I would still need to change the power supply from 277V.

I have no experience with buck transformers, so I need a little help on what exactly I need to order and if anyone has a preferred on-line supplier.

 

[GoldDigger]

No, this pole is supposed to be 277V. This is a car dealership with many adjoining properties and different voltage systems on all of them. This one is a a 480Y/277V system.

How would I size the buck transformer?

You would find a transformer which has a primary voltage of 277 or higher and a secondary voltage of 40 volts or more when given a 277 volt input.
The power rating it would need would be to support a secondary current equal to the AC draw of the power supply when delivering maximum output. Since the max DC output of the supply is ~60 watts, that would be .5A or smaller on the AC input. If the secondary is 48 volts, you would need at least a 24 VA (.024kVA) transformer.
You do not need the buck transformer to be rated for the full VA of the intended load, just (crudely speaking) the difference between the power at 277 and the power at 240 (or lower.)

 

[gar]

131101-1734 EDT

wirebender:

Just get a small control transformer that can be wired 480 to 240. Connect the 480 primary to your 277 and the transformer output will be about 140 V. Automation Direct has a 50 VA 480 to 240 transformer. I believe this is big enough for your purpose. They also have a 277 input transformer.

The advantage of the 480 input unit is that it would have a lower residual transformer loss when operated at 277, and I believe that your actual load was quite small. Thus, with under-utilization of the transformer the transformer loss becomes important. If the load actually approaches 50 VA, then the 277 V transformer is probably better.

.