Your solution with one power supply looks good to me, I use it all the time. One thing to note, the goes into and the goes out of currents are not the same. Starting with 12 V and going to 5V will reduce the 12V current requirement. It will reduce by the source voltage divided by the end voltage plus efficiency loss. To keep calculations easy I just use 10% as most buck regulators are much better and the cushion does not hurt. This is how I would calculate it, all of the loads totaled 5A at 5V. 12/5+10% So 12 / 5 = 2.4 + 10% .5 = 2.9A. If different voltages are involved calculate for each one and add the totals.
Many times you can eliminate the fuse if the buck converter has a current limit, many are adjustable.
What is the 2.9A that you calculated? Is it the current flow for each connection?
And where does 5A come from? My power supply has an output current of 10A.
I plan to use a buck converter to reduce the voltage for some components: 5V for the Raspberry Pi, 5V for the LCD screen, A4988 will stay at 12V, and 5V for the ESP32.
If I use a buck converter with a current limit, is it unnecessary to use a fuse, or is it still advisable for added protection?
Hi everyone @awneil@gilshultz@groundFungus ! Check this circuit connection that I made. What do you think about this connection? Will this be okay? I just added the buck converter to the circuit except for motor driver. Additionally, currently, I am using a 22 Awg wire.
Calculate the maximum current for each device and multiply by 1.5 for a safety factor and use that fuse. 22ga wire is safe to 7A so that would be the maximum fuse rating to use. 5A fuses will probably be fine.
The main power supply should have current limit at 10A. #18 AWG copper should support that without any problems. The Buck Converters have current limit so they should protect themselves. If you must have a fuse use 1 to protect everything, that will be much more reliable.
A 22 ga wire can handle 10A, if it's run through free air at 30C, and has insulation which can handle temperatures above 105C. It will handle about 40 amps before the copper melts (fusing capacity).
Regarding the circuit connection I sent here, what do I need to change or adjust? Given the components and 22AWG wire that I am using, are the fuses correctly placed in the connection, or do I need to place them on another connection? What would my final circuit connection look like?
As @awneil has pointed out, most don't bother but if you want to prevent against any wiring going up in smoke from an inadvertent short circuit somewhere put a 10A fuse directly at the output of your power supply and run all the wires to your circuits from there.
Why use three buck converters? I'd use just one. But, if you're going to use three, the one feeding the ESP32 could be / ought to be 12 v to 3.3 v, not 12 v to 5v.
