From the NeoPixel Uberguide
30 LEDs: 9 Watts (about 1.8 Amps at 5 Volts).
60 LEDs: 18 Watts (about 3.6 Amps at 5 Volts).
144 LEDs : 43 watts (8.6 Amps at 5 Volts)
30 RGBW LEDs: 12 Watts (2.4 Amps at 5 Volts)
60 RGBW LEDs: 24 Watts (4.8 Amps at 5 Volts)
144 RGBW LEDs: 57 Watts (11.5 Amps at 5 Volts)
The led needs its own power.
If your microcontroller and NeoPixels are powered from two different sources (e.g. separate batteries for each), there must be a ground connection between the two.
When using a DC power supply, or an especially large battery, we recommend adding a large capacitor (1000 µF, 6.3V or higher) across the + and – terminals. This prevents the initial onrush of current from damaging the pixels. See the photo on the next page for an example.
Adding a 300 to 500 Ohm resistor ohm resistor between your microcontroller’s data pin and the data input on the NeoPixels can help prevent spikes on the data line that can damage your first pixel. Please add one between your micro and NeoPixels! Our NeoPixel rings already have this resistor on there
Pro Tip: NeoPixels don’t care what end they receive power from. Though data moves in only one direction, electricity can go either way. You can connect power at the head, the tail, in the middle, or ideally distribute it to several points. For best color consistency, aim for 1 meter or less distance from any pixel to a power connection. With larger NeoPixel setups, think of power distribution as branches of a tree rather than one continuous line.