My Plan For A Cree Cxb3590 Light Bar

[Junk]

How flat is that sanding pad? I always just use plate glass and wrap it with wet sand paper.

If you have to start at that low of a grit those things must be extremely dished.

Some of the smartest people I have ever met have been maintenance techs. And holding a job has nothing to do with your value as a person, or to this community. I have learned a lot from you, and others have as well (we all talk about you behind your back)

I think you are the shit.

 

[testiclees]

fellas, my jawn is glowing. Thanks to RS for the last minute support.

It seemed like the ladies were very turned on by the addition of the cxbs

@Junk, testing seems to indicate that the OC attention to the heatsink is not worthwhile. If seaslug isnt looking to get involved speak up on the main diy forum (riu). There are several aces building killah setups commercially over there. Or check with RS he is a master himself.

 

[seaslug]

Thanks, Junk. I'm a caregiver 24/7 and my patient has been needing more attention.

The sanding block is very flat and just as importantly, the ABS plastic is rigid. Junk, do you use glass as a sanding block? My 3.945 heatsinks are warped 0.0105 across the width. I took the first one down to 0.0045 with files before ordering serious abrasive sheets. I haven't tried using my electric palm sander. The Makita takes square quarter sheets while the Preppin Weapon uses quarter sheet strips.

Feel free to post whatever design questions here and whoever is here please chime in. If I ever get a working model together, I'll post a separate tutorial thread.

Instead of cutting my 3.500 x 32" heatsinks in half to make deep/far red bars, I will use them in the veg room. Three 36Vf CXB3590 5000K per Mean Well HLG-80H-C700A. The drivers will be mounted on 3.5 x 12" aluminum shrouds with a central 80x25mm 120VAC fan. Design details to follow, here is the layout--COBs not to scale. 25W per COB, dimmable to 15W.

 

[seaslug]

I just realized how well this plan would work passively, with just a little air movement in the room. The dimmers will be set low. The heatsinks were originally going to be used for passively cooled reds.

Even a single, smooth running 80x25mm fan can wreck the stealth of a fluorescent grow room. (I have a Procyon 100 I was playing with.)

 

[testiclees]

on the procyon i see the coverage stated is 3x3. Seems ambitious for a lamp that measures 5" x 13".

Is that coverage claim accurate?

 

[seaslug]

The greenpinelane site, whatever it was called, put the coverage as 2 feet x 2 feet. I just had a single hempy pot under it for a while and some clone cups on the side. The plants like it but the Procyon runs hot and draws 125W (3W diodes, I forget the blue/red counts).

 

[seaslug]

I forgot to add, just about half the length of the Procyon is LEDs. That end gets hot--I can keep the back of my hand on it for 20 seconds but it's not comfortable at all. Procyon Depot is still offering these for :eek:$499 (with free shipping!) The Procyon 300 has been stuck in beta stage for a long while.

The blurple colored light from the corner of the basement is a potential stealth killer. I can't tell what my plants look like under this. The Lumigrow units have some warm white that make things OK as I see it. A number of people advocate special glasses for LED growers. The Cree manual mentions blue as the big threat because of the high energy and your eye doesn't react to blue as much.

Design note: The end plates block effective air flow through the heatsink fins.

 

[seaslug]

 

[testiclees]

i had blurple light for a while. the white cobs are a relief to work with in many ways.

The optic vero is a quiet light with far better dollar/watt ratio and verifiable quality cobs and drivers.

 

[seaslug]

The veg bar, driver adjustable from 45W to 75W total power to the COBs.

Edit: CD bin for flux

 

[seaslug]

Calculations:

CXB3590 36V Electrical Characteristics:

Estimated voltage at 700mA:
37.25V @ 2800mA (Tc = 25C)
34.75V @ 1400mA
2.5V from 34.75V = 32.25Vf assumed at 700mA.
3 x 32.25V = 96.75V
Edit: if passively cooled, the Tc=55 curve would likely apply and voltage will be lower.

Efficiency of HLG-80H-C700A in this circuit:
96.75V / 129V = 75% load, just over 90% efficient according to the graph.
Fully dimmed: 420mA / 700mA is 60%. 60% of 75% equals 45% load and the efficiency is just under 90%.

 

[testiclees]

View attachment 528783

Calculations:

CXB3590 36V Electrical Characteristics:

Estimated voltage at 700mA:
37.25V @ 2800mA (Tc = 25C)
34.75V @ 1400mA
2.5V from 34.75V = 32.25Vf assumed at 700mA.
3 x 32.25V = 96.75V
View attachment 528784

Efficiency of HLG-80H-C700A in this circuit:
96.75V / 129V = 75% load, just over 90% efficient according to the graph.
Fully dimmed: 420mA / 700mA is 60%. 60% of 75% equals 45% load and the efficiency is just under 90%.
View attachment 528785
View attachment 528787

Cool. i run the cxb 3590s 72v @.7mA. Plants love em so far still acclimatizing.

 

[seaslug]

I can't edit my calculations, the whole post is screwed up. The V-I graph should be extended using the line from 1400mA to 2100mA. That makes the calculated Vf closer to the nominal 36V (33V) and my illustration is wrong.
At Tc=25:
3 x 33V = 99V
99V x 700mA = 69W
99V x 420mA = 42W

 

[testiclees]

hey ss could you explain th poo se equations a little further?

Does your math show that you are increasing the voltage but not the current? I admittedly am at the most basic level of understanding the mechanics of ssl.

I thought the cobs had a relatively fixed voltage range. Im hlg120h 700c version a. I believe the driver efficiency at my utilization is ~90-92%. Both pairs pull 118-119 on the kill-a-watt.

Can you explain your watts and efficiency further please?

 

[seaslug]

Cree doesn't expect these COBs to be powered at less than 50W, I guess, so the chart starts at 1400mA . (50W = 1400mA x 35.7V) Looking at the green line, for a case temperature of 85 deg C, the voltage at 2100mA is 35.25. At 1400mA, the COB forward voltage is 34. So due to the electrical characteristics of the LEDs, the voltage goes down 1.25V when current is reduced by 700mA.
The forward voltage at Tc=85 with 700mA should be about 34v - 1.25V = 32.75V for each COB.

What the Voltage vs Current graphs show us is the importance of low case temperature. The lower the temperature, the higher the forward voltage and we get greater power at the same current (compared to a hot COB).

100% load on the driver would be LEDs with Vf adding up to 129V at 700mA. Proportionally, 33V x 3 = 99V and 99V / 129V = 77% load on the HLG80. This can be dimmed by 60% (420mA / 700mA) and 60% of 77% would be 46% load on the driver. Looking at the Efficiency vs Load graph, efficiency is 89% at the minimum circuit load (46%).

 

[testiclees]

Sea, When iwas trying to calculate the efficiency of the driver i simply added the vf of the pair of 72v cobs and approximated that i was around 90% efficient. Im wondering if my math makes no sense at all. I was using the attached graph.

 

[Junk]

Cool. i run the cxb 3590s 72v @.7mA. Plants love em so far still acclimatizing.View attachment 528788

You find any real benefit from the uvb?

 

[testiclees]

You find any real benefit from the uvb?

its only been a couple days. only difference noted so far is an increase in odor. it might be from the uvb or maybe just a factor of the plants maturing.

I was thinking that any benefits probably would not be noticeable until closer to harvest.

I did do a bunch of research and i thought that science does support the claim of uvb increases potency. We shall see in a couple months.

 

[Junk]

its only been a couple days. only difference noted so far is an increase in odor. it might be from the uvb or maybe just a factor of the plants maturing.

I was thinking that any benefits probably would not be noticeable until closer to harvest.

I did do a bunch of research and i thought that science does support the claim of uvb increases potency. We shall see in a couple months.

I didn't realize this was your first round with it.

When you are done, I would be extremely curious if you notice any difference. Even if you "think" you notice a difference... I'd be curious.

Despite the science, I've been told by a fellow grower that it didn't make any difference. But there are so many factors involved we don't know what is responsible for a lack of noticeable difference. I think I'm going to add one eventually.

 

[testiclees]

I didn't realize this was your first round with it.

When you are done, I would be extremely curious if you notice any difference. Even if you "think" you notice a difference... I'd be curious.

Despite the science, I've been told by a fellow grower that it didn't make any difference. But there are so many factors involved we don't know what is responsible for a lack of noticeable difference. I think I'm going to add one eventually.

sure i will certainly post my impressions.

ive heard arguments on both sides as well. completely agree with so many variables its nearly impossible to tease apart which inputs have which effects.

I thought that there was enough tantalizing support for uvb that it was worth giving a try. it was less than 100 for the bulb, fixture and shipping.