Quick question on led panels

[KingTweezy]

What's the lowest wattage you can go on led panels?
So I can do some research and buy them.
I've found these two for about 40 bucks a piece. They may be good but then again they could be too low?

Help please!

 

[Amadeus Forzin]

I use a 300w full spectrum LED panel and want more light