On January 20, 2019 at 12:48, highfigh said...
Here's a chart for wire gauge, with current limits. It shows the resistance for 24ga wire at about 25 Ohms/1000 feet, so you would cut that to ~25% by combining the wires...
The resistance of two of the same conductor in parallel roughly equals the resistance of a wire three numbers larger on the chart. Frinstance, two #4 in parallel are about the same as a #21. Take two such setups and parallel them, and you'll effectively have 18 gauge. It's worth sticking in your brain somewhere that a CAT5 cable, using all conductors, is roughly equivalent to an 18 gauge pair.
... and further to 20% of that number if it's 200', so it would be around 1.2 Ohms.
Yes, roughly. But...
You would be better off using a regulated power supply rated for more current than trying to send higher voltage.
Oops, that last assertion doesn't pan out.
A power supply rated for more current will be able to output more current than one rated for a lower current. But you're talking about somehow getting more current out of a supply at 12 volts than out of another supply at 12 volts, with the same load each time. That won't happen. 12 volts divided by the same load in two different setups will be the same current.
What WILL happen, that might influence things, is that if you have an unregulated supply, its output will float up to about 16 volts when there's no load on it, and it will.... it should... output nice clean 12 volts DC when the supply's rated load is being drawn. Important: an unregulated supply will output more volts when less than its rated load is drawn. When more than its rated load is drawn, it will drop slightly from its rated voltage and hum will be introduced into the output voltage.
The thing that's creating/being a load will cause heat- if the wire has no resistance, it will cause no heat and therefore, no voltage drop. Also, if the temperature of a conductor increases, the resistance increases, too. It's counter-intuitive, but that also increases the current if the power is to remain constant. It's what causes a weak car battery to kill the starter.
While that might be true, it's like mentioning the food coloring you'd use to make gummi bears while telling someone how to make boeuf bourguignon. It's the same field, and it's a fact, but it doesn't help and might even confuse someone who's thinking the answers are all related things.
And I still haven't had the time to actually write my response to the original question.
