Matrix of WS2812b powered in 24v (LEDs 5 by 5)
Good way to smoke a load of LEDs!

They draw current depending on the individual unit brightness settings, so this will not work (Among other reasons having to do with the need to level translate the data between each stage). 

Use a small switching regulator to take the 24V down to 5V and use that to power them in the normal way. 

Regards, Dan.