For sure you won’t be able to run these LED at full power “white” with one (or even 2) powerbanks, or else it’s going to overload (and then cut off) the powerbank (it has a max Amp protection). I barely run 200 LED with a 2.4A powerbank. Might be a bit weak if you want to push luminosity or avoid cutoffs.
However in practice you don’t need full white 100% luminosity, especially for a wearable (I assume it’s for Burning Man ? :)).
Therefore it’s not even sure you will need to do this many injection points.
I’d recommend to do tests to see if you actually need these injection points, i think beginning and end (not even sure it’s needed honestly) are more than enough, especially if you cable from the power with AWG16.
To give you an idea, I run 2x 200 LED behind 40cm of AWG18, and i have no noticeable voltage drop at 100% power = 25W per strip = 5A !!! Considering your powerbank is 3A max = lower voltage drop. You can start your tests with feeding power only at the beginning of the strip (with data).
You can indeed use 2 powerbanks to increase the power (less LED per powerbank) or battery life, however make sure these 2 powerbanks have their +5V separated:
- All GND connected together (all LED + Powerbanks + Pixelblaze) else you gonna have data issues
- 5V Powerbank 1 on Pixelblaze and LED strip 1
- 5V Powerbank 2 on LED strip 2 (cut the 5V link between the 2 strips)
Hope it helps !