Watts vs PPFD: which do you use?

[Delps8]

those numbers might not mean anything in the real world.
far too often the maps are mostly marketing. plenty of times the mfgr hasn't done an actual measurement. even when they do it is not third party independent testing.

things always change once a fixture is installed as well. the size of your space and added bounce can help, and definitely changes the map. one tip i give to new folk is to buy a rig one size up from the size of the grow space. if they run a 2 x 2 i'd recommend a light rated for a 3 x 3 .. etc.

Re "real world" - very true. Best way to know how much PAR is hitting a plant it so measure it. Lacking that, I used the best available info. And, if you check the PPFD maps on their site, they're pretty vague. Each map is a series of squares representing 1'. In the very center is, not in any square, is a very high value (1259 IIRC) then there's a value of 10xx, and then the edge value that falls off the table. But, since he got the light for free, as I understand it, he can't knock the price!

"things always change once a fixture is installed as well. the size of your space and added bounce can help, and definitely changes the map"
No doubt about that.

 

[TorturedSoul]

Also a lot of LED mfgs do their PAR testing inside reflective tents, which is inaccurate to the real world and cheating IMO.

Er... Because in the real world, more people grow cannabis in an integrated sphere (or a corner of a big, open room) than in a grow tent, lol?

I'm cool with the measurements being done inside a grow tent. That way, if I get anal about prepping/painting a space, I can probably expect a couple of percentage points of improvement.

I'd prefer the tests be done in a tent that's the same size as mine, however. And... you know... no lying.

 

[Icemud]

Er... Because in the real world, more people grow cannabis in an integrated sphere (or a corner of a big, open room) than in a grow tent, lol?

I'm cool with the measurements being done inside a grow tent. That way, if I get anal about prepping/painting a space, I can probably expect a couple of percentage points of improvement.

I'd prefer the tests be done in a tent that's the same size as mine, however. And... you know... no lying.

Integrated spheres generally aren't used for PAR mapping but more PPF which is total photon output and spectral analysis, especially in the days of omnidirectional HID bulbs.

For cheap "home grow" type fixtures it's not as important but for large scale facility development, it becomes an issue.

Overall its just not an accurate representation of the light, IMO.

 

[TorturedSoul]

Yes, it's going to depend on the use case. I should have acknowledged that. Apologies.

 

[The70’s]

My current subs are 15” AdireTumults from about 2004. I use (4) sealed, and drive each one with a QSC1450 bridged, my theater is about 2.2K sq ft and they have been putting a smile on my face the whole time :0)

So, im not opposed to spending money on a Par meter, you guys are wayyyy beyond my current knowledge, but in order to give my plants the best possible lite food, what meter, and will this allow me to push this tent a little further than i m now with out torching them, or under powering them….

 

[Mayne]

man, get the UNI-T from the zon, and multiply lux by 0.017, $24

 

[The70’s]

man, get the UNI-T from the zon, and multiply lux by 0.017, $24

I have a DrMeter and i used .015 it was $28

 

[Mayne]

I have a DrMeter and i used .015 it was $28

that was actually the first LUX meter i bought and calibrated few years ago. The reason i use the UNI-T is because its very very consistent to apogee 500 when converting the lux. Migro did a Utube video with i think 4 different lux meters and the UNI-T was the most consistent. thats why i ended up getting it and converting it.

 

[bluter]

Me, too. And I followed my own advice when I chose the S44 instead of the S33.

good idea. at least you can trust the advice ..

I like that - "Grade 2 bogus".

i personally try to avoid mfgrs like that.

That works for Whitman's but if they spec the components of a product, I think it can be successfully argued that they're required to provide the product specified. I did just one term of law - contract law - and it was in the Great White North but our legal system has a lot of similarity…except in Louisiana.

actually it's quite common. there's a number of folk on this board who've ordered rigs that did not come advertised spec. the big one is of course the most active board sponsor named for a planet ...

a 10% cost savings on a driver is nothing to sneeze at. a 320 watt HLG retails at $100 so Mar is paying $30±? If they can drop that off of the cost and keep their price up, that goes right to the bottom line.

i've replaced hlg's with elg's myself. as long as the driver is spec'd correct it won't matter. the elg has greater dimming options, and a better warranty. it's more for commercial apps.

What DLI's do you use?

i don't exactly follow it as i have other conditions to work around. i'm generally pretty good when glancing at the charts for interest though.

I saw your comment about show lighting - tons of change their, eh? Thinking of which, I did a project for Live Nation Studios in the late aughts to help manager post production. Fascinating stuff.

Re. "before" - must be interesting to see the technology evolve. $64k question - who's your favorite manufacturer?

for show gear ? mac has been the go to for over 20 yrs now. i like a lot of mac movers, robe is super good bang for the dollar in movers too, and i used to mix a pile of cheap static lumi's in. we tore the lumis apart and rebuilt them to our own show specs.

i used hog boards, mac, and etc. for audio we were all ev x-array and line array. 4 different rigs that could be broke in to 8 smaller shows if needed. 2 - 5000 pax is about the sweet spot for the size rigs we ran on big shows. smaller shows would be about 1500 max.

I have a DrMeter and i used .015 it was $28

for home gear it'd be just fine. i wouldn't spend a pile.