If you are open to HPS I'd say go for it. You will get better yields and happier plants for the money. You can get a 600 watt HPS cool tube setup for $170. I have two Mars 600s for flower and am thinking of changing up to HPS, I use metal halide for veg.
I do have a cool tube, Http://www.amazon.ca/Apollo-Horticulture-GLK600CT24E-Digital-Dimmable/dp/B00521B894
I'll be feeding them tonight so I'll get in the box and see if I can reduce the U some more.
As for exhausting, currently the box is in my garage/barn, and it's exhausted into the room it's in. I have 2 fans one in the main part of the garage moving air and another fan pointed at the intake holes blowing cooler air in.
I'm thinking that I could make a type of swamp cooler with ice packs for day time temps (since I run day at night and night at day)
52 cubic feet! (6'h x 3.5'w x 2.5'd). Adjustable ballast Apollo Dimmable Can run at 75% and 50%. Starting at 75% and will go full power during flower. Got this one for the best value and size of tube for the space.
I'm telling you, get the package with the cool tube or your tent is gonna get real hot
https://www.amazon.com/dp/B00521B894/ref=twister_B01N30KRTU?_encoding=UTF8&psc=1
So. I could put a cooling tube http://www.amazon.ca/Apollo-Horticulture-GLK600CT24E-Digital-Dimmable/dp/B00521B894/ref=sr_1_3?ie=UTF8&qid=1427552022&sr=8-3&keywords=600+watt+hps run it horizontally (front to back) with the booster fan only for the tube. Then run an actual fan http://www.amazon.ca/iPower-GLFANXINLINE4-Ducting-Hydroponics-Applications/dp/B0085GTELM/ref=sr_1_5?s=lawn-garden&ie=UTF8&qid=1427552199&sr=1-5&keywords=fan with filter for smell venting? I want get away from building a glass enclosure for the light, hence the cooling tube or full hood, want.
> Or you could hop on Apollo Horticulture 600w air cooled digital MH/HPS ~200$ and get a higher yield than that
Yeah, price & yield are definitely factors.
On the Apollo, would you recommend the cool-tube model
Or the standard air-cooled version:
Definitely worried about heat in the smaller tent.
600w hps with a fan and filter. you're going to want a fan and filter regardless of the lights you use, and the 600 hps will beat those two panels at a fraction of the cost. just duct the exhausted air out of a window and you won't be running much hotter than the leds.
if you're dead-set on led, look into cobs or go with a couple cheaper panels imo. maybe a couple of these. the ones you linked are really expensive and aren't going to be enough light for that 4x4 tent.
I would suggest you pick up a cheap horticulture setup and DIY something like this http://www.amazon.com/Apollo-Horticulture-GLK600CT24E-Digital-Dimmable/dp/B00521B894/ref=sr_1_5?s=lawn-garden&ie=UTF8&qid=1441934626&sr=1-5&keywords=Apollo+Horticulture+600+w , that is what I did when my brother in law got cancer and I could not find anything, a small investment for a really big payout and it's so easy even a retard like me could do it. need good seeds and I can point you in the right direction as well.