160423-2344 EDT
Jeromyk:
You are asking for a simple answer to a question, and you have not yet figured our how to ask the correct question.
If I have a power source with a rather typical circuit breaker on its output, and I want reliable operation, then I don't want to load that breaker to its full rating. If I have an electronic current limiter that can be precisely set to some value, then I also don't want to load it to that limit, but I might go closer to the limit than on a thermal type breaker.
Now to what is the question to ask. You must first determine the characterustics of your load. Likely you have electronic loads with some sort of internal regulator to provide constant voltage to the electronics. This would make the load a constant power load when that load is at a steady state condition. This means the load current as seen at the input terminals of the load is inversely related to the voltage across those input terminals. Lower the input voltage and the current increases. This would be the case with a switching regulator in the load. The modern way of doing circuits.
If the regulator in the load is a series pass type, then the input current would be approximately constant.
You have to know your load characteristics. You can run experiments to determine how your load works.
The device I am powering is the equivalent to a cable modem. This device operates at 20W base but also provided POE power to externally connected devices that could increase the total Watts to 100W.
This statement is your critical ctiteria. If you have a 100 W load at 50 V and this is a constant power load, then at 50 V at the load input terminals the input current is 2 A. If that input voltage is 45 V, then its input current is 2.22 A. Basic electrical circuit analysis tells you where to measure voltages and currents. You need to find a book on this subject.
For a pure stable resistor in a DC circuit V = I*R, P = V*I or V^2/R or I^2*R. Where V is the voltage across the resistor (load), not somewhere else in the circuit, and I is the current thru the load.
Around any closed loop the sum of the voltages is 0. At any point in a circuit the sum of the currents is 0.
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