what load will be "decided" when I connect it to the battery?
The battery IS the load. The current that flows out of the regulator will be the output voltage of the regulator minus the battery voltage divided by the ESR of the regulator, battery, and wiring. (Vr - Vbatt) / ESR
it would be impossible for the regulator to control both voltage and current with a variable load, that would violate Ohm's Law
how would that violate ohm's law? you for example put in 10W (5V@2A), the regulator makes it 2.5V@5A (still 10W), the load will get destroyed or won't work properly or something, but there still is only 10W
You also can't have a regulator that outputs a constant voltage and adjusts its output current based on power input
input 24V@1A, this goes to regulator which is connected to a battery, the regulator makes it 12V@2A, 24W at both times
we put 48V@1A to the same regulator (lets say it is capable of that), the output voltage of that regulator is 12V, so the current becomes 4A, 48W at both times
how is that violating ohm's law?
Conservation of energy != Ohm's Law
Ohm's Law is I=V/R. Current through the load is equal to the voltage dropped across the load divided by the resistance of the load. Neither the source nor the load can control two of these parameters, because then the equation would force the third parameter on the other device, which is impossible. If the regulator were to force both 12V and 1A output, then it would essentially be telling the load, "You are 12 ohms", but the load's resistance is a property of the load, the regulator can't tell the load what its own resistance is...
One of the three values is controlled by the source, usually "V". One is controlled by the load, usually "R". The third one (usually "I") is the result of the equation.
let's say I have 12V 10Ah battery and a 78S15 regulator (15V, 2A, I guess those are output LIMITS?)
Regulator output resistance is 17 mOhm
Battery internal resistance is 20 mOhm
input limit for that regulator is 35V, so let's say my wind turbine is producing constant 30V, the output of the regulator will be 15V
what should I do to calculate the current going to the battery? 2 scenarios that came to my mind, most likely both incorrect;
1, the battery "eats" all 15V that it gets from the regulator, right? so Vr-Vbatt = 0, doesn't matter what resistance there is, I got no voltage... what now?
2, let's say a battery somehow "eats" only 14V, so I have 1V left, the resistance of battery and regulator is 37 mOhm, I have no idea what resistance is from the wiring, but let's say they're all really close together, let's say the wiring resistance will be 63 mOhms, so total of 100 mOhm, since I have 1V left, 100 mOhm resistance would give me 10A, but since regulator has limit of 2A I'm getting 15V@2A and the rest is dissipated as a heat?
I guess both points are absolutely wrong, so how do I correct them?
in first case there's no voltage, kind of a dead point, but that seems to be illogical, as battery SHOULD "eat" all voltage - how do I get the current then?
the second case would most likely destroy the regulator due to heat, also if there would be no limit for current, it would output 150W, since the voltage input was 30V, the current input logically would be 5A, which seems to be possible, or? therefore I'd be losing 120W as a heat, which is absolutely terrible