I have a few of these set up with no problems, however my longest strip of 10m has intermittent flashing between centre and furthest end (from connection). It does seems to work fine on some effects however.
It is only connected at one end via a standard ESP32 and powered by a 300w supply. For ease do I need to split the length in half or could I add a power injector to the other end perhaps?
Distance issues where the strip fades/loses colour/flickers are typically voltage drop issues, implying the need for more injection points.
Couple of ways to test:
Simplest is to use a voltmeter and measure the voltage across the strip as you move farther from the nearest injection point. You want a solid display with white at 100% (or reduced brightness till the flashing “just” stops)
A little more complicated, but can be useful to eliminate a “bad” strip - Create a segment that is only the last 1/2 (or 1/3, 1/4 as required) of the strip and run that at 100% White. You’ll see the effect of lower current (because you’re not lighting all the LEDs in your strip) passed through the whole strip to power the end LEDs. You can add length from end-back to the beginning until you see issues start to appear.
The voltmeter is the best, most direct way to see what’s happening with your power supply to the LEDs.
If you don’t have one, get one, they’re on the order of $25 for a reasonable digital device but they’re an essential tool to work with LED setups.
Either method will probably point to the same thing - inject more power.