you won't find a quality light for a 4x4 or 4x5 space at 0.
if you only run autoflowers, you can use fewer watts and sufficiently cover a 4x4 or 4x5. if you intend to grow photoperiod plants in a space like that, you will need a true 600-some watt light... the more efficient the better... good lights cost a bit more upfront, but will save on each monthly electric bill for 5-7 years of use, or more. in some cases, your driver may fail before teh diodes dim below 90% of original intensity... (the longevity curve gets a steeper decline as time, i.e. it dims at incrasing rates, although slowly at first)
The lamp linked below lists smd 3030 diodes... this is a generic term. the LM301 is an smd3030 chip. SMD - surface mounted devices. 3030 = size of the diode. Since they do not list the manufacturer, that's a BIG and bright red flag warning you to stay away. the one good thing it has going for it is that it is runniing the 972 diodes at a fairly low per chip wattage.. without exact spec sheet, there is no way to see L90 (point at which it is 905 of intensity on longevity curve) or any number of important specifications about this chip... this doesn't happen on accident. Lack of information improves their sales. the info will most likely push you away from their product so they make it impossible to see.
never trust teh par maps if they don't give the spec for your diodes... An anecdote that is a parallel -- Day 1 the very expensive Luminus COB LEDs are stronger than the cree cob LED (comparing top of the line of each manufacturer at the time -- luminus whatever vs cree cbx3590 something or other) Anyway.. day 1 the luminus is brighter but within just 10,00012,000 hours of use it will quickly dim relative to the Cree COBs. if you only used it 12/day for bloomphase, that's only 2 years of use before it starts dimming like the total piece of shit they are, LOL, while the cree cob continues to give you intense light similar to day 1 for another 40,000 hours. it lasts 5x as long.
So, longevity and efficacy are two things that are often glossed over by the cheap lights.
i'd suggest saving up more money... buy onen off alibaba if you want the lowest price. can probably get a 600-somew lm301 chip "bar or strip style" light with better even coverage than a qb for less than 0 to 0 delivered. Or, pay 900-1200 somewhere else for the same thing.
If running only autoflowers, could run a 480w high efficacy light in same space. This is directly proportional to hours of use.. 12 hours vs 18 hours or more, etc. you need 2/3rds the amount of light over 18 hours vs 12 hours and still provide same DLi to the plant. This would obviously be a cheaper light.
alibaba has some risk. make sure the vendor is covered by "Trade Assurance." It involve negotiating directly with a manufacturer, which is not comfortable for all ppl. the initial listing will only show the lowest, cheapest configuration, even if it lists something else in the title... lots of bait and switch going on. salesmanship wiht zero integrity.. kinda par for the course worldwide if you don't split hairs. you may even find a generic SMD3030 - if licensed from samsung this is going to be a lower bin options but still can be okay if in greater numbers. this is an additional risk that the vendor isn't just lying to you to sell you a piece of shit BWahahahah... but hey... such is life.
anyway, i'd save up a bit more... or, piecemeal it... buy a light to augment what you got but in future can be paired with another one to properly cover teh space... this way you could spend a bit less today... cover more space while also using your old equipment.. then in future buy a 2nd one to complete it. ~480w for autoflowers in a 4x5 and 600-some watts if doing photoperiods in a 4x5... this assumes it is somewhere near 2.7-2.9umol/J efficacy, otherwise a few more watts might be wise.
