You're stretching there in the argument, you stated, " What do you know about voltage drop. It is my opinion you have this backwards in your head."The problem with large voltage drop is the change of volts that is dependent on the amps drawn. Not a great way of controlling charge input.
Nothing in my response said anything about charge input. But I digress, we shall have the discussion on several fronts. First, do you know the most accurate way to measure VD on a wire with no addition/subtraction or any other type of math, no calculator and gives 100% accurate results every time? If you don't, I'd be more than obliging to explain it to you.
Second, charge input is controlled by DC to DC charger which also is a step up converter in this case, 12v to 24v. Input 30a, outputs 15a. Watts in equals watts out minus some loss for the converter but that isn't relevant to the discussion. Output voltage is regulated by the DC to DC charger.
As for your response in the block above, you have voltage drop attempting to control amps from the way you worded it. It can be done, I don't know why you would want to waste energy as heat on a charging circuit but go for it. Take blower motor resistors, the amps drawn by the motor will be less, however the total amp draw with the resistor in the circuit will be the same regardless of speed, note I did not say load. A given load however will increase amps over a lighter loaded condition but still, the circuit with the resistor installed will still draw the same amps on the complete circuit with the increased load, motor will still draw less amps than with the resistor in the circuit. Not a hard concept to understand.
Now, let's look at the DC to DC charger, 12v to 24v step up type and the wiring required. On the 12v side, amps will be double and requires a wire size according to those amps. On the 24v side, the wire size can be 1/2 as only 1/2 the amps will be carried by that wire. Watts across the circuit remain the same, except for converter loss. In the case of a Victron 12/24 DC to DC, input is 12v 30A, output is 24v 15A.
Now. I'll really mess with your head. Take a length of wire and pass amps thru it to power an incandescent light bulb. Record the result. Now, add resistance to the circuit in series at the exact same voltage. Will the circuit draw more,less or the same amps? Correct answers only.
Second, is VD the same on a given length of wire at different voltages? Again, correct answer only.