Hi i have a ups to power my hap ac3 but the maximum output voltage is 12 volt will that effect the efficiency of my divorce in the manual it’s said that it can run from 12 to 28 volt but i am wondering if 12 volt will give me the maximum efficiency ?
Not sure about the efficiency of your divorce, but the device should work equally within the given input Voltage from the specification sheet (12-28V)
..in theory, the overall efficiency should be better with higher voltage…if you would notice a difference from within that range is another question.
When running on 12V only, the required Current to supply the same level of power will be (more than) doubled from that of the standard 24V supply.
Keep that in mind and decide if your UPS is able to supply that Current (A) level.
Also, with 12V supply, I doubt that the PoE-Out port will be functional to drive another device in the chain.
Hi,
Assuming buck converter is used here, efficiency is fairly constant over input voltage range.
Efficiency can actually be slightly better at lower input voltage. TI document DC/DC converter efficiency https://e2e.ti.com/blogs_/b/powerhouse/posts/increase-dc_2d00_dc-converter-efficiency-understanding-operating-modes-and-power-losses
@Hominidae had power wire resistance in mind … the higher the current, the higher loss (and voltage drop). Which is a thing well worth considering when powering device over ethernet wires (due to their high resistance due to low cross-section and length) but not so much when using normal power adapters with their short and (relatively) thick wires.
I use my ac3 with 12v battery instead of UPS. Half year all works fine.
You need to break down the issue into three seperate problem.
Problem 1: Target Voltage/Current
You need to know the Power requirement of your device.
Voltage is easy, because you only have 12V..
Current is a bit more tricky…
It depends HOW you use the hAP ac³
I think you should consider ~ 18 Watts (device + USB-Port, no PoE-Out)
This means 12V@1.5A
Problem 2: Transportation
a lot of Factors imfluence the delivery of electricity over a distance.
For exemple temperature, shape of conductors, interference to name only a few.
When powering a small Device indoors, you usually only have to take into account,
- Cable-Length
- Cable-Quality
- Connection (DC-Jack)
With 12V@1.5A you wont be able travel long distances. But the main limiting factor isnt the Cable but the 5.5mm Jack.
- I wasn`t able to find any DC-Jack for thick Wire (>0.5 mm²)
- DC-Jack have “relatively” high resistence
I dont see any problem with a cable up to 3 m. If you want to push the limits maybe 4 or even 5 m will work... But i wouldnt go any longer.
Problem 3: Efficiency of device
I dont own a hAP ac³ , so i cant confirm this…
But I am very sure, the lower the Input-Voltage, the higher the Efficiency.
So for exemple 12V should be more efficiant then 28V