I’ve completed projects coat projects with 250-300 LED’s with no issues but inject power through micro usb. But I’m still a novice and I have questions on power injection and number of power banks.
Run a single 3A power bank, keep max brightness low. Connect at LED #350, and LED # 700.
2 power banks with 3 injections. 1st powers beginning + PB, 2nd injects at middle and end. Have all ground connected, but keep 5V separated by cutting 5V link between the 2.
I likely prefer the first for simplicity. I have a 10kmAh 3A battery bank that I’ll be using. Thoughts? I don’t want to glue them all the lights and then fry them.
I think you already got this, but just to clarify you definitely want power at the start of the strip and to PB as close as possible. This helps ensure the first pixels get nice clean data and no glitchy/flickery LEDs. Then yes, injecting into the middle and end is also good. if you didn’t have enough power injection the main problem you’d likely see is color shift and loss of brightness and only for high power patterns.
If you draw too much power from a power bank, it will probably just cut out for a moment. You might see a flash on the LEDs and PB resetting. Some have to be plugged in to charge at least momentarily to reset, but are less common.
If possible, have a quick way to disconnect the LEDs while still powering PB - that will make it easier to recover from problems where you set brightness too high or run a power hungry pattern that overloads your power bank.
With SK9822/APA102 type LEDs you can drop brightness way way down and still get good color mixing. With WS2812 / SK6812 type LEDs they will start to drop colors at low brightness.
A lot depends on the pattern too. Patterns with a lot of black could probably run at full brightness, like fast pulse. Patterns that light up everything, and use a lot of white can be very power hungry.
I JUST tested a project doing exactly what you indicated – I’m just powering at LED1 (where the PixelBlaze is; ensures clean PB power) and LED 700 – so the spot with the most “drop” is actually the middle. As long as the brightness is down / the LEDs aren’t all-on, it works fine. I wouldn’t bother also injecting power at LED 350 for a wearable, and instead just pull back on brightness and patterns that leave a lot of lights on at once.
This is great info, thank you both. I’ll test with injecting at the end and see how that works first. Especially good to know about power banks and how to reset, as I literally just did that and thought it was dead until I plugged it back in.