On the specs page it mentions current 2A and voltage 7-57V.
Does that mean that it can deliver a total of 114W of power? (57Vx2A=114W)
That doesn’t sound right for such a tiny device with such a tiny power input cable.
What’s a realistic maximum power that this PoE injector can handle?
I need to power an airFiber24 (50W) using 54V input voltage. I was hoping I could power it directly from a netPower 16P but it can only handle up to 0.6A per port, so I will have to power it directly from the 54V UPS on site (losing the ability to remote power-cycle, unfortunately).
RBGPOE doesn’t deliver power, it only passes power. I guess power limit on PoE-out devices is due to ability to power-off/power-on the port and to select output voltage (if device has two power inputs) and both imply some active circuit. RBGPOE has none.
Max voltage depends on isolation class of elements used (e.g. voltage rating of capacitors or isolation breaking voltage).
Max current depends on internal resistance of device which translates to heat generation. And current rating of elements used (e.g. inductors, resistors, …)
Bullet #1 doesn’t depend on actual current flowing through device. Bullet #2 doesn’t depend on voltage between wires.
And as @zacharias already wrote, P=U*I (in plain words: power equals voltage times current).
In theory, according to its specs, it can handle 114W. 57V x 2A = 114W.
But how much power can it handle in practice?
Better yet, has anyone used one of these to power a Ubiquiti airFiber 24, which according to its datasheet it can draw up to 50W?
Will it work long term or will it burn out after a few months or during summer heat?
Well … nobody’s gonna offer their neck to put under axe for long-term functionality. Sure gadgets do get aged. Aging means capacitors might leak (which might mean lower sustained voltage … with 50V supply voltage it might lead to loss of smoke). Aging means corrosion, corroded contacts mean higher resistance, with high current that means more heat generated, high temperature might lead to loss of smoke. Device powered with 50V but drawing 0.3A can still cause high-voltage aging problems. Device powered with 14V, drawing 1.9A, can still cause high-current aging problems. Device powered with high voltage and drawing high current can cause both and life expectancy might be lower than in one of other cases.
But then … RBGPOE is rated at max 57V and is rated at 2A, and there’s nothing in specs indicating that there’s some U*I product which should not be exceeded.
And, as I wrote before: with passive elements voltage-related problems are mostly orthogonal (read: unrelated to) to current-related problems. Which means RBGPOE should handle 57V 0.2A (11.4W) equally well as 12V 0.2A (2.4W) … at the same time it should handle 12V 2A (24W) equally well as 12V 0.2A (2.4W). So why should 57V 2A (114W) be a bigger problem?
