48" LED Array - Up and Running...Mostly

[Canadian]

Great build. And you've done a great job of documenting things for everyone to mimic should they so choose.

But I have to comment on the PAR. Your old T5 fixture is not a very good comparator for a moderately good T5 fixture. Your PAR values with the T5 fixture are abysmal and not reflective of typical high quality T5 fixtures with 54W lamps (presumably your reported T5 PAR values are with new lamps as well given you're comparing this to brand new LEDs). Secondly, the PAR values with your DIY LED fixture are still quite low. Every time a discussion about LEDs comes up the comparison to 250W and 400W MH is made. These numbers clearly show they aren't even close in the manner in which you've designed this fixture. I've maintained that until real numbers for PAR are measured and reported the propaganda of "equal to a 400W MH" is absurd. So far the data I've seen do not support the marketing BS. In all honesty, did you expect the PAR values to be that low?

And as far as lifespan goes: again there is no long term data for PAR as far as I know (unless you have info I haven't seen yet). T5 lamps have a reasonable lifetime but their effective PAR drops much faster. At this point we don't have any good data to support the numbers being batted around about 50,000 hours lifespan. Sure, the emitter may continue to emit light for 50,000 hours but at what PAR?