How many HPS equivalent watts?

I have been reading up on comparing LED output to HPS output and a lot of the info I have found is from years ago and not using my LEDs lol I get a common question from my friends and would like some calculations to explain ~how many watts I would have in HPS terms.

For example I have a friend who has a 600w HPS and I would like to know how our lights compare.

I am not sure the brand but he has a 600w HPS w/reflector and has been using it for about a year now, his grow area is ~4x4.

I have
(4) CXB3070-0000-000N0HAB30G-ND LED ARR 23MM 3000K 80CRI 8500LM @ 1.4A
(1) Meanwell HLG-185H-C1400B
(1) CXA3070 Z2 @ 1.2A
(1) Meanwell LPC-60-1400

in ~3x3 area.

I have been reading that PAR is the best way to compare the two, I have been doing reading and have read a lot of things about needing $$ equipment.

Does anyone have some good old calculations they can show me lol

Thanks in advance

So after doing some more reading and finding some answers in some older threads I think I have an idea.
I found the most helpful info from @Supra in https://www.rollitup.org/t/space-requirements-for-600w-of-cree-cxa-3070.828701/
as well as some internet searching lol

From what I have gathered PAR W and umol/s is the way to compare. I have found some calculations and worked them through and this is what I came up with.

Using Cree's Product Characterization tool I found that my system (had to use cxa3070s instead of cxb3070s though!!!)

1 cxa3070 @ 1.2a = 5,439lm
4 cxa3070 @ 1.4a = 24,754lm

Total = 30,193lm in the 3K spectrum

(30,193lm) / (269lm/w) = 112.24 PAR W (calculation from wiki page at bottom)

Grow area 3x3 = 9ft^2

So
(112.24 PAR W) / (9ft^2) = 12.47 PAR W/ft^2

According to Supras conversion of 4.88umol/S for each 1 PAR W

(112.24 PAR W) * (4.88umol/S) = 547.73umol in my 3x3 grow area

Read that it is recommended to have 800 umol/S/m^2
I have 9ft^2 so about .8m^2

800 umol/S/m^2 * .8m^2 = 640 umol/S would be ideal for my grow area

Ideal - 640 umol/S
Current - 547 umol/S

I used the table and info from the Photosynthetically active radiation wiki page.

{
For example, a light source of 1000 lm at a color temperature of 5800 K would emit approximately 1000/265 = 3.8 W of PAR, which is equivalent to 3.8*4.56 = 17.3 µmol/s.
}

Any thoughts or corrections lol

Here is what I come up with.

@ Tj 50C:
(1) CXA3070 Z2 = 44W * .4 = 17.6 PAR W
(4) CXB3070 AB = 200W * .454 = 90.8 PAR W

108.4 PAR W / 9= 12.04 PAR W/ft²
106 * 4.88 = 529 umol/S /9 = 58.78umol/ft² * 10.7 =
equivalent average intensity, 629 PPFD.

All that is assuming PPF = PPFD but there are some lateral losses. At 1.4A I highly recommend using a lens or reflector because the distance between the COB and canopy is large enough that it makes a huge difference in intensity

SupraSPL said:

Here is what I come up with.

@ Tj 50C:
(1) CXA3070 Z2 = 38W * .4 = 15.2 PAR W
(4) CXB3070 AB = 200W * .454 = 90.8 PAR W

106 PAR W / 9= 11.77 PAR W/ft²
106 * 4.88 = 517 umol/S /9 = 57.47umol/ft² * 10.7 =
equivalent average intensity, 618 PPFD.

All that is assuming PPF = PPFD but there are some lateral losses. At 1.4A I highly recommend using a lens or reflector because the distance between the COB and canopy is large enough that it makes a huge difference in intensity
View attachment 3388327

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Ok so looks like my calculations were ballpark. Thanks again for taking to time to crunch some numbers!

I already read your reflector post and added the 4 reflectors to the CXBs last week, I noticed a huge difference in intensity as you said!

So sounds like I have a pretty solid light for my space right?! I have a decent PPFD and PAR W if I am not mistaken....

Yes I think that is a good intensity to run with.

@SupraSPL ,
How did you calculate those conversion factors?
Did you integrate the density functions over PAR (400-700nm) or extrapolate them from known references?

heckler73 said:

@SupraSPL ,
How did you calculate those conversion factors?
Did you integrate the density functions over PAR (400-700nm) or extrapolate them from known references?

View attachment 3388465

Click to expand...

That's exactly how we come to these numbers.

Yep, and the 4.88 umol/s/PAR Wfor the CXA3000K curve came from Mr Flux's calculus. He revised some of his numbers at some point but I believe that is the most up to date. Does your number agree with that Alesh?

SupraSPL said:

Yep, and the 4.88 umol/s/PAR Wfor the CXA3000K curve came from Mr Flux's calculus. He revised some of his numbers at some point but I believe that is the most up to date. Does your number agree with that Alesh?

Click to expand...

Yes. I'm getting 4.87 μmol/J.
For reference, it's ranging from 4.6 μmol/J for cool whites to 5.0 μmol/J for high-CRI 3000K and HPS spectrum.

Awesome info man thnx!

SupraSPL said:

Yep, and the 4.88 umol/s/PAR Wfor the CXA3000K curve came from Mr Flux's calculus. He revised some of his numbers at some point but I believe that is the most up to date. Does your number agree with that Alesh?

Click to expand...

Thanks. When I saw your scalars without units, it left me wondering how you got them.

I also found Flux's source code.
Good stuff.

https://www.rollitup.org/t/cree-cxa-analysis.743645/#post-9764122

Some light sources I've digitized:

Efficiency multiplied by this value is equal to actual production of photons per energy dissipated [aka μmol/J aka μmol/s/W].

So in conclusion, as long as you have 1 blue led for every 3 red leds, you should be all set... right?

churchhaze said:

So in conclusion, as long as you have 1 blue led for every 3 red leds, you should be all set... right?

Click to expand...

Correct, and you should yield about a pound

I have to say church half of your posts I feel are super informative....but I think you have some troll posts out there and I love it hahahaha every once in a while I'll be reading an old thread and church pops up with his infinite wisdom or some trolling that is too funny lol