so ive been lurking here for like 6 months reading everything i can and finally pulled the trigger on building a 5inch freestyle quad. got a diatone Roma L5 frame which seemed like a solid middle ground for price vs quality, and im running a F7 stack with the 45amp 4in1 ESC underneath. thing is i keep reading conflicting stuff about whether i should be running the ESC power leads directly off the battery leads or going through the capacitor first and honestly at this point ive watched like 8 different build videos and they all do it slightly differently.

i did my first round of soldering last night and its... passable i think. the XT60 joints look okay but im not super confident about the motor phase wires, they feel secure but theres a tiny bit of flux residue i havent cleaned off yet. is that actually a problem or do people just leave it. also im using 63/37 rosin core which someone here recommended a while back, using a Hakko FX-888D so temperature shouldnt be an issue, running it around 350c.

main question i guess is the cap situation and also whether i need to do anything special with the ESC signal wires going to the FC or if plug and play is genuinely plug and play at this point

the cap question is pretty simple once you think about it ? the capacitor goes across the battery leads on the ESC, not between the battery and ESC. so you solder your XT60 leads to the ESC pads, and then the cap legs go to those same pads or as close as physically possible. its job is to smooth out voltage spikes from the motors, not to filter incoming power. most 4in1s these days have a cap spot built in or come with one, so just use that and dont overthink it.

flux residue from rosin core is generally fine and not dangerous but its worth cleaning anyway, isopropyl 90%+ and a toothbrush takes 2 minutes. some people say it can cause issues over time in humid environments or if theres alot of it, personally ive never had a problem leaving it but i still clean it out of habit. and yeah FC to ESC signal connection on a stacked build is genuinely just plug it in, the stack is designed for that. check that the uart assignments in betaflight match what youre plugging into but thats software not wiring.

dude im literally doing almost the exact same build rn except i went with the GPS rescue setup which added like 3 more wires to the nightmare lol. the phase wire thing stressed me out too but i continuity tested every motor connection before powering up and that helped me feel better about it. also dont forget to do the smoke stopper thing on first power up if you havent already, saved me from a bad time when i had a short i didnt know about