While some things are designed to be run from USB such as the water pump in my cat's filtered water dish, sensitive electronics the likes of which I can't come up with an example just now - require a more pure source of power. Chargers are not required to be clean sources of power. Just sources of power. My dad's old car battery charger had a 12V AC source rectified with a single selenium rectifier. As a kid I wanted to use that charger to power a car radio. Got a HECK of a lot of hum. Knowing nothing about electronics, someone told me I needed a filter cap. So I got my hands on something like a 16V electrolytic cap and put it in series with the power. The radio barely played at all. Put it across the half wave rectified lines the radio played but still had a horrible hum. So I tried putting the cap before the rectifier. No change. I then put it across the 120VAC primary. BANG! That was exciting.

The whole point is a charger is meant for charging batteries and not necessarily for powering electronics. Your cameras will probably require a better power source than a charger. And please don't think calling a wall wart a charger is the same thing as a bonified power supply. There are different flavors of those things as well. A power brick may charge the batteries in a laptop computer. But it can also run the computer because it was designed to do so.

What we're telling you is this: If you have a clean 5V source with 6A capacity (30 watts power) then you can hook devices parallel on that power rail that do not exceed 30 watts. Three 1A cameras, each drawing 5W will equal 15W. A 5V 6A Clean power source will have no problems powering your cameras. Maybe! As I mentioned, I had a different experience. One camera on the PS was fine. Two - had distortion. All four - had distortion. Plug any single camera into the PS and it was good. DO NOT ask me why that was. I don't know.

 

ie if devices is low cost it can feed noise onto the PSU and affect all other?

It isn't whether the device is low cost or not that affects whether it can feed noise onto the power supply. It's the nature of the circuits in the device. Anything that varies demand on the power supply is a potential source of noise, but digital circuits can be more problematic.

 

Anything that varies demand on the power supply is a potential source of noise, but digital circuits can be more problematic.

which implies the solution mentioned time ago -> Each device = separate PSU

Maybe case as the 3 identical devices/cameras -> one PSU (but thats with question also as u mentioned, bc noone know how these cameras internals behave what they feed ... )

@Tonyr1084 i do use old Phone chargers to power some 5V devices (luckily w/out issue)
I was expecting that wall 2x usb socket which costs more than cheap charger should behave fine, especially from renowned brand as schneider, but who knows now.

 

which implies the solution mentioned time ago -> Each device = separate PSU

No. More than likely, the devices will operate well from a single power supply.

Maybe case as the 3 identical devices/cameras -> one PSU (but thats with question also as u mentioned, bc noone know how these cameras internals behave what they feed ... )

I installed a surveillance system that had 8 cameras. It was intended that 4 cameras operate from each of the 12V supplies provided with the system.

 

Hello,
i have 3 Amazon Blink cameras, each 5V 1A.
Can I power all of them using once PSU - 5V 6A?

Thanks

Yes. My truck has one battery (power source) with the truck not running that single power supply (battery) will run everything on and in the truck. Long as the demand does not exceed my available power things work just fine.

Ron

 

@MrChips i think i was told some time ago,
that if u have for example 12V 5A, and two different devices lets say 12V 1.4A, 12V 1A ... its not a good idea to connect them both on one PSU.

thanks

If that were the case, then you would need separate batteries for nearly everything in your car, since your dome light takes considerably less current than your headlights and your brake lights are somewhere in between and so forth.

If you can remember who told you that, the next time they tell you something about electricity, nod your head and say, "Okay, thanks," and then immediately forget whatever they said.

 

which implies the solution mentioned time ago -> Each device = separate PSU

No, it means that devices that are connected in any way (and even if they aren't connected), that they will communicate with each other via noise. What matters is how much noise one part creates and how susceptible to noise the other part is. For lots (most) applications, this is not a problem that even needs to be considered. But sometimes it is so important that you have to make Herculean efforts to deal with it.

 

Think of that power supply in your wall. You plug in lamps of all different wattage. Plus TVs, stereos, computers, toasters, washing machines, phone chargers.... rarely are there any problems.

 

What is the longest run from PSU to camera? What is the distance between the two most separated cameras?

 

Mister Chips got it in post #8! It all depends on both the power supply AND THE WIRES connecting to the power supply. Inadequate wiring will prevent proper operation from even a "perfect" power supply. (zero noise and zero voltage change from no load to full load. In addition, any resistance in a connection feeding shared loads will cause some coupling between those loads. That may cause problems in some instances.

 

@MisterBill2
said multiple times, i do not understand his #8 second point
2) Isolation
Conceivably, some devices require positive voltage on the PSU center pin while others require negative voltage. This is not a problem if there are no interconnections between devices. If devices share a common ground, you need to check that the power adapter and signal connections are compatible.

Note: Not all wall adapters are floating. You need to check for compatibility between devices and power adapters if the adapters are not isolated.

Inadequate wiring will prevent proper operation from even a "perfect" power supply.

i dont understand why inadequate wiring is concern here. The assumption is the wiring will be properly done.

In addition, any resistance in a connection feeding shared loads will cause some coupling between those loads. That may cause problems in some instances.

this one i dont get.

 

MisterBill2 said:


In addition, any resistance in a connection feeding shared loads will cause some coupling between those loads. That may cause problems in some instances.

this one i dont get.
OK, here is the detailed explanation of what happens: If there is a resistance in the positive supply prior to the point where two loads are connected, then by ohms law, the current flowing thru that resistance to load one will cause a voltage drop of some magnitude, and so the voltage at that point will be reduced. Since that point is also effectively the voltage supply point for load number two, as well as load number one, load number two will have a lower supply voltage, the same as load number one. THAT reduced supply voltage is what I was referencing: "That may cause problems in some instances." Functionally it is a classic "ground loop", although maybe not so obvious.

 

@MisterBill2
why there should be mentioned resistance? " there is a resistance in the positive supply prior to the point where two loads are connected, "

 

Does each camera have its own cable back to the power supply, or are they daisy-chained along a single cable ?

 

hi,
so i bought 5V 6.5A meanwell. From PSU i run 10m 1mm2 stranded cable; so i increased votage on psu to 5.2V (bc of power drop).

When i start to add devices
a) 0.1A zwave temp meter
b) 2A https://www.home-assistant.io/voice-pe/
and lastly
c) 1A blink camera

the total Voltage drops to 4.95V

In case i send some voice command to b) which utilizes power consumption of the device, during that period/peak voltage drops even more to 4.8V

1)
So i am wondering why such a voltage drop is happening, even i have connected total 3.1A on 6.5A PSU?
2)
also when i disconnect and connect camera - the device b) got rebooted somehow


The mains from PSUs DC are connected to 5pole WAGO (each pole +,-) and the above mentioned devices are attached to the remaining free slots on wago (so its not in series etc.. )


Thanks

 

https://forum.allaboutcircuits.com/threads/power-sockets-dc-devices.207935/post-2009449

 

does anyone has any idea if i can used close to endpoint devices these modules;
https://www.pololu.com/product/4082

that should prevent voltage drop and stabilize 5V output, even in case the input voltage goes lower to 4V (bc of V drop)

thanks