cree3590cxb high efficiency setup: driver and layout questions

Greetings RUI community! Been living on here for a few weeks soaking up all I can from you amazing DIYers. I'm about ready to put together an order for Jerry from Kingbrite, but I am not sure about which drivers I should use with this setup.

What I need is a super efficient setup for extreme heat/humidity zone, with limited amps available on circuit. Clearly the cost of this setup will be high but so would upgrading my main breaker box/ adding new circuits/more exhaust/fans/another A/c. Very poor attic access due to really low profile roof complicates things even more.

So with that said, this light will be for a 4x4x7 flowering tent. With this setup at 1.05 amps, the cob calculator is showing 1107.4 pppd on full power. Most of the time, due to heat, I want to use a potentiometer to dial down to around 700mA amp settings for more effeciency @ 741.4 pppd). My assumption is that 1.05 amp driver with a pot attached would give me flexibility to lower the heat watts/raise eff when I need. Here is a list of parts I put together and a few questions I have about some of them.


18- CXB3590CD@36V 3500K
18- LED holder: Ideal 50-2303CR
18- LED adaptor: Ideal 50-2300AN
18- LED reflector: KB-D82-90RF
18- SST120 Passive Heatsinks (about the same price but more effective than finned heatsinks, from growmau5 tests. These pinned heatsinks are predrilled which is nice)

Ok here is where I'm a bit stumped, my driver choices:
3 - HLG-185H-C1050B 95V ~ 190V @ 6 COBs each: will this increase efficiency, by lowering voltage per, or cause issues? Looking at supraSPL's 1500watt 3590cbx thread eff. list on page 2, 5 COB on this driver will work out to 35.5w per at 61.4% eff. Am I right to guess this will further lower the wattage per cob , to what I can only estimate to be about 29.6w per?
OR

2- HLG-240H-C1050B 119 ~ 238V running 9 COBs each @ < 26.4 watts each. I don't quite understand how to get exact wattage per COB using driver/cob info yet.
OR

Any other driver choices than could keep my eff at 61%+, keeping in mind that I could increase cobs/drivers to keep PPFD at 750-900.

For a layout I'm thinking
@-@-@-@-@
@--@---@--@
@--@---@--@
@-@-@-@-@
Not perfect uniformity but my thought is it would be pretty close with proper spacing, but I'm certainly open to suggestions.

I am a bit confused on how the cob calculator can determine PPFD, heat watts, ect, if number of cobs per drivers and per cob watts isn't taken into account. I don't want a setup that under powered so I could see adding more cobs or drivers to keep the efficiency up.

I would love to get some others insight on my plans, thanks all!

1. For constant current drivers and generally speaking... The drivers you may want to buy needs an output voltage that is high enough to power the number of the chosen number COBs.

For example: the CXB3590 has a forward voltage(vf) of 36 volts and a series of COBs is 6. Multiply the forward voltage by the number of COBs in the series. (36vf x 6= 216 volts output from the driver.) In this example a meanwell HLG 185H-C700B with a maximum output voltage of 286 at .7 amps will suffice to cover the series of COBs with some extra to spare. The meanwell HLG 240H-C1050B with a maximum output voltage of 238 volts at 1.5amps will suffice as well.

2. Greater driver efficiency will be a result of the being able to keep the driver cooler and or forcing the driver to power a chosen series of COBs at less than full power. Since heat will transfer from the heatsinks to your custom built frame and gradually to the driver. It is easier to keep the driver cooler, If you do not attach it to the COB array fixture.

3. Build your COB array fixture first and keep educating yourself in areas you do not have complete understanding. Waiting until you understand absolutely everything will only hinder yourself from doing something. Remember if you do not use previously gained knowledge your depth of wisdom never increases.

The HLG-185H-C1050B can only run 5 CXB 3590's. It has 195V and 6 COBs in series would need 216V (6x36) as Rayne says.
For 18 COBs I'd use 3 HLG-240H-C1050B. You can dimm from 10% to 100%.

juq said:

I don't quite understand how to get exact wattage per COB

Click to expand...

W = V * A;
So (in the case of CXB's) 36 times the amperage of the driver:

0.700A * 36V = 25.2W/per COB
1.050A * 36V = 37.8W/per COB
1.400A * 36V = 50.4W/per COB

Finally my ahah moment! thanks @Rayne and @Desmond J !

So my new plan is to go with
22- CXB3590CD@36V 3500K
22- SST105 Passive Heatsink : This is a reduction in hs size, and will still provide more cooling than it needs at 700mA. Slightly lower price as 18 of the larger size as well. rated at 25-35 watts or 20 heat watts, and my cobs will run at 25.2 W. If anyone has any concerns about this decision feel free to let me know.
2- HLG-320H-C700B (214~428 constant current): 428/36 = 11.8 COBs So I will have a little breathing room.


From the cob calculator 22 COBs at @700mA will give 909 PPFD, with 64% efficiency, only 539 W at the wall and only 181 heat W! I do of course plan on keeping the drivers out of the tent, my inline fan will be outside of it, keeping only lights, carbon filter and circulation fans inside.

New layout of
@-@-@-@-@
-@-@-@-@-
-@-@-@-@-
-@-@-@-@-
@-@-@-@-@

juq said:

Finally my ahah moment! thanks @Rayne and @Desmond J !

So my new plan is to go with
22- CXB3590CD@36V 3500K
22- SST105 Passive Heatsink : This is a reduction in hs size, and will still provide more cooling than it needs at 700mA. Slightly lower price as 18 of the larger size as well. rated at 25-35 watts or 20 heat watts, and my cobs will run at 25.2 W. If anyone has any concerns about this decision feel free to let me know.
2- HLG-320H-C700B (214~428 constant current): 428/36 = 11.8 COBs So I will have a little breathing room.


From the cob calculator 22 COBs at @700mA will give 909 PPFD, with 64% efficiency, only 539 W at the wall and only 181 heat W! I do of course plan on keeping the drivers out of the tent, my inline fan will be outside of it, keeping only lights, carbon filter and circulation fans inside.

New layout of
@-@-@-@-@
-@-@-@-@-
-@-@-@-@-
-@-@-@-@-
@-@-@-@-@

Click to expand...

thats pretty sweet, where did you find that PPFD calculator?

juq said:

What I need is a super efficient setup for extreme heat/humidity zone, with limited amps available on circuit. Clearly the cost of this setup will be high but so would upgrading my main breaker box/ adding new circuits/more exhaust/fans/another A/c. Very poor attic access due to really low profile roof complicates things even more.

Click to expand...

Could you elaborate a bit on this? What do you mean?

juq said:

Finally my ahah moment! thanks @Rayne and @Desmond J !

2- HLG-320H-C700B (214~428 constant current): 428/36 = 11.8 COBs So I will have a little breathing room.

Click to expand...

Just so you know those two drivers are going to be pulling a combined ~7a from the wall, not to be confused with the output current. I just say that because of your comment in your original post about having limited amps available. Perhaps you already know this or arent concerned but figured Id at least share the info in light of previous comments

Desmond J said:

The HLG-185H-C1050B can only run 5 CXB 3590's. It has 195V and 6 COBs in series would need 216V (6x36) as Rayne says.
For 18 COBs I'd use 3 HLG-240H-C1050B. You can dimm from 10% to 100%.


W = V * A;
So (in the case of CXB's) 36 times the amperage of the driver:

0.700A * 36V = 25.2W/per COB
1.050A * 36V = 37.8W/per COB
1.400A * 36V = 50.4W/per COB

Click to expand...

Very true. But remember, at lower currents, like 1800 & lower, the forward voltage of the cobs is a bit lower. Not by much though. Like at 700mA I think it's right around 35.2?

@BlackD.O.G https://www.dropbox.com/s/hqgj9n5qxb9xrei/DIYCOBLEDCalculator.jar?dl=0 You will need the lastest java to open and use this app.

@Shugglet So I see what you are saying, from the specs on this driver, thankfully I do have room on the circuit for 7amps. My thinking was that with a wall pull of only 547W , with a driver power factor of .98 (listed on specsheet), on a 110-115 V, single phase outlet, my amps pull would be at 5.02-4.8. Is my thinking wrong on this? http://www.rapidtables.com/calc/electric/Watt_to_Amp_Calculator.htm This is the amp calculator I used to come up with that.

What I mean about limited amps on circuit, is basically I want efficiency and low heat to avoid having to add more fans, larger ac, due to living in a hot climate. I'm lucky to have a bit more startup cash to wait for the benefits of the extra savings in electricity bills down the line as well. I can add 1 more 15 amp circuit if needed soon, but space for a 3-phase/240 or more is unlikely.