Thanks very much for the patient explanation. I am familiar with Ohms law (even took E&M in college, years ago...) The problem that I've been having has been in understanding ampacity practically (as well as theoretically). This shouldn't be too much of a surprise to you as you wrote:
Ampacity can be found in wire gauge cables as well, but is much more complex
To do all of my permanent installations, I've relied (almost exclusively) on:
Quindor's 5v/12v Power Sheets; and,
Quindor-recommended RapidTables' Voltage Drop Calculator
This comment from you thru me through a loop:
Remember that voltage is lost on both the power and the ground wires, so double the length of a single wire. That is, if you have a 40' two wire power feed, use 80' in your voltage drop calculations.
Whoah! Really? I didn't see that in any of the Quindor stuff nor on the voltage drop calculator sheet. If it were that way, I would have expected Quindor to have called it out in his video (this is probably the right video and link)
Clearing that up for me would help tremendously. And from what I can tell, would help a bunch of other non-EE/non-circuit-board-proficient WLED newbies.
Another adjacent topic is, of course, when to double up on power cables from the 5v power supply to DigUno/DigiQuad. I use the same power supply all the time (overkill, but the money difference doesn't matter to me, and Quindor recommended Mean Well as one that provides good consistent clean output, so if that's important to him, then I'm good with that as well. Standardizing just makes it easy for me). Anyhow, I use this Mean Well RSP-320-5 300W 5 Volt Power Supply. I've seen Quindor double up copper from power supplies to DigUnos/Quads in a video of his before (can't recall which one), but I never understood why nor when to do that myself. There are only three pairs of 5v +/- terminals on the PS, so if I double up copper with to the DigiQuad, then I'd have to use separate terminals (do I though?) leaving only one pair left... so I could only power one other DigiWhatever run from that PS. What am I missing here, both on when to double up, when/how to do that with the terminals, and how much amperage (right?) each terminal can take, so can I theoretically have lots of "small" runs and controllers off of one pair of terminals?
Oh, so many questions. I've put most of my power/amperage ones here. Not that I expect you to answer them all, but I think I'm def not even a minority of <1 year WLED hobbyists who do not understand this. So it at least helps me organize my thoughts.
Thanks again for your thoughts and help. Now that I'm in front of my computer I can give you other details about my setup if you'd like.
And have a great day!
edit: formatting of links and, of course, typos, and stupid stupid stupid autocorrect problems (as always!)
Done with
WS2812b 30 led a meter from ali express - https://m.aliexpress.com/item/4000148759042.html?trace=wwwdetail2mobilesitedetail&spm=a2g0o.productlist.0.0.31b0496bY6NbUa&algo_pvid=56a8ccf4-2587-4064-a50e-7653b784ee42&algo_expid=56a8ccf4-2587-4064-a50e-7653b784ee42-2&btsid=0bb0623416018538910112493e4388&ws_ab_test=searchweb0_0,searchweb201602_,searchweb201603_
40 pack aluminum channel from amazon https://www.amazon.com/dp/B072W186LK?ref=ppx_pop_mob_ap_share
One Dig Quad from quindor - https://quinled.info/pre-assembled-quinled-dig-quad/
200 feet of 18/3 cable from amazon - https://www.amazon.com/dp/B01M22ZU7X?ref=ppx_pop_mob_ap_share
One meamwell 300W 5 volt power supply from amazon - https://www.amazon.com/dp/B00IWC2RLS?ref=ppx_pop_mob_ap_share
One six way fuse box from amazon - https://www.amazon.com/dp/B07FTLGH5J?ref=ppx_pop_mob_ap_share