Number of Power Injections every 50 cm?

Issues
1

Inject power “every 150 LEDs” they say.

Common connectors are JST-SM connectors which support max AWG 22 with 0.92A_max (American Wire Gauge Chart and AWG Electrical Current Load Limits table with ampacities, wire sizes, skin depth frequencies and wire breaking strength).

However, if every pixel takes around 0,06A, you would need to inject after every 15 LED (0,92A/0,06A) to cover peak performance,

On a 30LED/m strip, this would mean an injection after every 50cm.

Wow, this will be a lot of soldering. Or am I wrong?

2

Depends on whether your assumptions are correct.

Good ampacity tables reference the resistance of a given wire gauge over a given length rather than just a maximum current.
A piece of 22AWG wire can easily carry 10A or more with little change to your LEDs - if it’s short enough.

Similarly the “rule of thumb” for LEDs is often 0.3W/LED. That’s sufficient to get you a good size power supply that can reliably drive hundreds of LEDs. The precise draw of an LED in your strip can only be perfectly predicted by measuring some sample devices.

A digital multimeter with a 10A current scale is very helpful.

Measuring the actual voltage drop along your strip under “100% White” loading will always give you a better idea of how many injection points you might need.

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