The WS2812B datasheet tells you:
- Each pixel is 3 * 16mA = 48mA max per pixel. A 15A 5V power supply is required at minimum to power your whole strip at maximum white.
- The VCC voltage per pixel is a nominal 5V (the controller in the chip generates a 12V CC to drive each LED). The pixel will work perfectly from 4-5V and so you can support a voltage drop over the strip of 1V. If you have an adjustable power supply, then you could increase the input voltage to 5.2V to handle even more voltage drop along the strip.
The Magic controller does NOT modify the input voltage for its output VCC. While the Magic controller will run on voltages from 5-24V YOU CANNOT feed this through to your LED strip. The maximum EVER for your strip is 5.3V and 5.2 as maximum is advisable.
The Magic controller instructions say the following:
Model: SP105E Bluetooth Magic Color Controller
Working voltage: DC5V~24V ( Please choose the correct power supply according to you led lights. If your light's working voltage is 5V, please use a 5V power supply, not 12V/24V power supply. )
Remote distance: 20 Meters
Product size: 85mm*45mm*22mm
It can support WS2812B, but there is no WS2812B option on the setting page. Please choose WS2811 when connect it to WS2812B.
The controller cannot regulate the output voltage at the VCC. That means the output voltage of your power supply must be the same as the work voltage of your led lights.
There are endless power supplies that might suit your functionality. For example Autove (who sell the Magic controller) offer this power supply on Amazon for exactly your purpose.
If you are going to use your strip at maximum white for long period of time, I'd suggest that you might want to use a 20A+ supply. Autove offer an example on amazon with this supply which has screw terminals providing a much better connection and current capability.
If you are concerned about the voltage drop along your LED strip you can run a pair of wires (VCC and GND) to each end of your strip to minimize the drop. The barrel connector on the Magic controller is inappropriate for 15A+ so you should be powering the LED strip separately as shown below:
Taken from this document.