I looked up the
actually wattage of the
Blackstar V2.0 and it turns out to be a 135W light. On Amazon it was
$288.95. Compared to the
A51 RW-75:
I don't understand the Blackstar v2 240w. Yoda said he has one and it pulls about 135w from the wall. I have the v2 180w and it pulls 118w (I used a kill-a-watt meter). That's a 15% increase in watts used for a 34% increase in LED capacity (180w to 240w) and 25% increase in cost. I assumed he got a bad light. But, what you found sounds like that's the way it works. In which case I'd have to rethink my suggestion that the 240 would be good for taller plants.
They probably did that because it was more economical to use more bulbs driven less hot than replacing the heatsink (because it's just a rebranded Chinese import and they don't have that level of customization available at the factory. One heatsink fits all orders.).
its driving me insane, every time i think i have one picked i hear more horror stories about it.
LEDs are a huge learning curve and there's so much predatory hype. A lot of rebranded Chinese lights sold at a premium. My first light was a Blackstar because it had decent results at least for shorter/compact plants like autoflowers. (As I said, I've gotten good results.). Looking back on it, I would go with a less expensive more direct import light like TopLED or Vipar (ebay). The former has a public support forum which should reduce the potential for warranty problems compared to buying from other (obscure) sellers from China. The latter is recommended by knowledgeable members as a "if you have to buy cheap" option. (But, there was a recent report of someone getting stiffed on a warranty after just 2-3 months use.).
If you can maintain the distance from light to canopy, get the A51 RW-75. Supplement with the Cree lightbulbs from Home Depot if necessary to get about 20-25w/sq. ft.
Or, you could just start with enough Cree lightbulbs to reach that w/sq. ft. I'm supplementing my Blackstar 135w/85w UFO with four lightbulbs. You might get some ideas from
my blog (<<link) where I link to CaptainMorgan's thread where he experimented with it a year ago. He broke 1g/w using only those bulbs. You can read his thread, but people seem to recommend warm:cool ratio around 1:2 or 1:1 for veg. 3:1 or 4:1 in flower. The logistics are a little complicated, 8-10 plugs. Reflectors, how to suspend/adjust the lights. There are "gooseneck flexible lamp extenders" in different lengths on Amazon (but they come from China, so you have a month wait). A bit more DIY which you may not want to do if you're already tired from the LED learning curve.
Whatever you do, I wouldn't let perfection be the enemy of good. Buy something and get started. Blackstar grows smaller plants well. (I got over 1g/w, 105g from 85-88w.). It's just going to boil down to your vertical space. More diffuse light (multiple weak sources like the light bulbs, a 3w unit without reflector like a UFO, a 3w with wide-angle reflector like Hans. A51 with its 5w and reflector might require more vertical space than you have?). Nothing wrong with replacing the light in 6-12 months and having a backup on hand.