I know Im new here but I actually have a little experience with LED's. Im assuming like Bulldog you are talking about the high output LED's (which have 1-5 watt led's), not the cheap x-mas light led's (which are 1/10 watt bulb's). <---those are crap.
If its a single panel LED light and is 300 watts, it has to be either 300 (1 watt led's) or 100 (3 watt led's). Either would be a very nice light given it was atleast the tri-spectrum or better setup. I have a 120 watt (120 led's each 1 watt) tri-spectrum, and I love it. It doesnt cover as big of an area as they rate it due to you having to have the light closer to canopy (during flowering esp) than normal growth for best results. You need it within 18 inches MAX from top of colas for real good results all by itself. I have found with using HPS and LED (both seperate and together), that a combination is the best of both worlds. LED's are coming down in price, saving on electric bill is great, and the no heat is the best of all. HPS is very proven, reliable, and realitely cheap.
Again, I find giving your ladies as many spectrums as possible is just that much closer to the real thing. Red (for flowering via led), blue (for veg via led) and either white or orange (as a third spectrum via led for max coverage or extra orange burst for flowering), and then add it the old reliable orange/red spectrum from the HPS. My led panel has white as the 3rd spectrum, so I prob benifited the most form using both. If your panel has orange as 3rd spectrum, u prob wouldnt see near as much benefit of using the HPS at same time. For example, instead of using 3 400 watt HPS's, I would reccomend using 2 400 watt HPS's and 1 300 LED for the room. You will have much better results and less heat issue. Hope it helped.
