For the WS2815, I’ve seen some data that max current is 36mA per pixel (so 22A for all 600); it also tends to use the same current for one color at a particular intensity as full white at that intensity. Power planning might be a little more important than for the 5V strips.
Let’s assume you are doing power injection properly across the full length (otherwise the rest of this doesn’t matter as much, since these copper traces on strips will not carry 22A for very long), and that our sole problem is just connecting 22A peak current and data at the beginning of this strip.
For reference, the JST-SM that comes on most strips is rated 3A.
All 4 conductors in one housing
If you want all 4 conductors in one housing, all the below come in 3 and 4 position variants.
Cheap to manufacture: xConnect and Ray Wu style. Claimed weatherproof. I’ve never seen a max current spec’d. Since they usually come as 18AWG pigtails, we can assume a conservative 3A in a bundle, or 16A in free-air.
You can use an audio XLR to 15A and Neutrik Powercon to 30A.
They typically have nice strain reliefs and durability but aren’t always spec’d weather resistant. I think that you can improve the weather resistance of these and JST-SMs by applying dielectric grease.
The automotive world has good weatherproof and vibration resistant stuff up in the Delphi Metri-pack systems, TE Superseal and Deutsch.
These are probably a well-engineered solution, but they get expensive for small projects if you buy the right crimpers, and slow to apply if you choose the cheap ones. I would choose these for stuff I want to live through multiple years’ visits to an alkaline dry lakebed.
I know you asked for 4 conductor options. For higher current connections, I’ve been wiring data separate from power. All the below options are fine or overspec’d for 20A. Most are not outdoor rated, but for short durations they seem to work fine (I’ve had many live through one season of rain/snow).
I’ve been using Anderson Powerpoles for power, but I think they’re kind of finicky on install, and I’m not efficient installing them. They have a great, convenient (re)connection feel though.
It makes fused distribution pretty easy with items like this:
From the RC world, soldered XT-60 connectors are also great for high current DC, though harder to disconnect.
I’ve also done power through crimped terminals (ring/spade), buttsplices, ferrules and blocks, but for speed nothing beats Wago 221 levernuts.
This last holiday season I’d splice data through them as well.
Did this help, or is it like there’s too many options now!?