PICO's DIY Thread - Advise, Ideas and Technology - NO PANEL REPS!

[smokey the cat]

Ok I'll bite, this talk about drivers is exactly what I'm trying to get my head around in designing a tiny DIY solution using vero. I've been looking at them for a micro grow - 2.2 square feet, only 90cm high. I'm envisaging a dimmable Vero string with 3 emitters in 3500k or 4000k, and a dimmable 16W string of red+far-red osram.

I want to be able to veg and flower so I need some with a bit of blue in the spectrum, so will be choosing slightly cooler Vero and having seperate red. The colder Vero are more efficient than the 2700k, which is nice.

Ok - Vero choice. I had been thinking of 3 x Vero 13 and running them at "max" current - say just over 1000ma. This gives me about 90W, though efficiency drops near max - the data sheet shows is only 180% when current is 200% of nominal.

Thinking about this though - the Vero 18 is around the same voltage, it just runs on twice the current. Wouldn't I be better of running 3 x Vero 18 and running them gently - say at the nominal 1050ma? Price difference is negligible.

The costly part of this is the driver. I'm looking for an a/c dimmable driver that puts out around 30V with enough current to drive three Vero in parallel. Here is Meanwell:
HLG-100-30 - 3.2A max - enough for 3x Vero13 @ max current 1060ma, or 3 x Vero18 at nominal
HLG-120-30 - 4A max - 1300ma per Vero
HLG-150-30 - 5A max - 1650ma per Vero - enough to push the Vero 18, but not to "max"

I'd love a regulated DC PSU like you have Pico, but I'm downunder and they're hard to find second hand. So I'll probably buy meanwell from the states and get pay heaps for shipping.

What driver-emitter combo looks good? I'm thinking Vero18 and the 100W @ 1060ma or 150W @ 1650ma Am I thinking of too much power? I only have 2.2 square feet.

Any thoughts?



To refresh everone's brain here is the Vero range, "max" current/watts is ~2x nominal, with headroom above that again.

Vero 10
Nominal Current 350mA, 26.7V, 9.3W

Vero 13
500mA, 32.5V, 16.2W

Vero 18
1050mA, 29.5V, 31W

Vero 29
2100mA, 38.6V, 81W

 

[MrFlux]

Smokey, for you space you would need about 50W of Vero power to get the the minimum target of light. Your projection is twice that which is great.

It is not advisable to run the Vero's in parallel, Bridgelux explicitly warns against doing that in the spec sheet. What you can do is put one driver per Vero or use multiple smaller Vero's in series. For example 4 Vero 10's can be driven in series by a cheap driver. Three of these strings and you're set. Can be passively cooled too if you want. It is not dimmable but you can turn on 1, 2 or 3 strings to select the desired power.

 

[lax123]

The driver constantly varies the voltage its supplying to the circuit, if the LEDs heat up the resistance normally drops, so you use less volts to push the amps through, if the LEDs cool down, normally the resistance will go up so you need a higher voltage.

Yeah thats right, and thats exactly the reason for using a CC Driver and having not to worry about anything else. It varies "automatically" the voltage, so that all leds get the nice current of e.g. 700mA or 1050mA....Pico you posted all kinds of nice links, why cant you provide one reliable source that confirms what you are saying is true.

 

[MrFlux]

Why do you not have to use resistors with CC's. If the chips don't fit the driver perfect then there will be some excess voltage right, what happens with it?

With a CC there is no excess voltage It is the job of the CC to provide the exact voltage which is the sum of all the individual forward voltages (at a given current).

You are thinking constant voltage supply, which is sort of the logical inverse of a constant current supply.

 

[tags420]

Yeah thats right, and thats exactly the reason for using a CC Driver and having not to worry about anything else. It varies "automatically" the voltage, so that all leds get the nice current of e.g. 700mA or 1050mA....Pico you posted all kinds of nice links, why cant you provide one reliable source that confirms what you are saying is true.

With a CC there is no excess voltage It is the job of the CC to provide the exact voltage which is the sum of all the individual forward voltages (at a given current).

You are thinking constant voltage supply, which is sort of the logical inverse of a constant current supply.

What a brain fart, pretty much should have just thought of the definition of a CC driver. I was just thinking they were both constant for some reason.

 

[PICOGRAV]

To refresh everone's brain here is the Vero range, "max" current/watts is ~2x nominal, with headroom above that again.

Vero 10
Nominal Current 350mA, 26.7V, 9.3W


Vero 13
500mA, 32.5V, 16.2W


Vero 18
1050mA, 29.5V, 31W


Vero 29
2100mA, 38.6V, 81W

The Vero 29 is only really max 1.5x normal current with not much head room after that, the absolute max before total destruction is just over 5 amps.

I would go with the 3 x Vero 18 and run them with an analog DC power supply like I have, it is going to be hard for me to recommend you run these in Parallel with no voltage control off one of those drivers.

This is the way you run high power LEDs in parallel:

"proper adjustment should be like this, turn all the knobs counter clock wise to zero, first middle out the fine volt and amp adjustments. Next give the amp "Course" knob a quarter turn clock wise, then work your voltage up from the "Course" voltage knob until the LEDs illuminate, keep increasing the voltage until you hit the current limit set be the quarter turn on the amp knob, once the you hit the set current limit DONT increase the voltage yet, LEDs will be very dim at this point. What you would do now is go another quarter turn or maybe a little more with the amp knob and then increase the voltage again, keep doing this until you reach the correct amps. At this point bring back the current by turning the course current knob counter clock wise just until you are on the edge if the current/voltage limiter. Now you have a dialed in current and you should leave the current knobs alone for the rest of operation, you can dim with just the voltage, always bring the voltage up and give it about a quarter turn past the current limit, so it will take up the slack if the LEDs resistance drops."

If you don't have any voltage limit on your circuit, besides what the driver will shut down at, you could start to see problems, also those drivers are PWM dimming, so even at a dimmed state you are still sending high voltage through, it is just pulsing it a given number of times a second, sorta like a really fast strobe light. I really dont like this way of dimming and this is where the analog power supply's trump the new cheap digital ones.

http://www.ebay.com.au/itm/30V-10A-Adjustable-Output-DC-Power-Supply-Transformer-Adaptor-3010D-/380764898135?pt=AU_B_I_Electrical_Test_Equipment&hash=item58a75b4357&_uhb=1

That's a Power Supply that could work in Australia, I sure you could find something for about $100-200, is that going to blow the budget?

 

[lax123]

another cheap Driver: http://www.ebay.com/itm/160927171205?ssPageName=STRK:MEWNX:IT&_trksid=p3984.m1439.l2649 950mA, 15-36V. Cant tell you much more except that they work as desired, got 5 of them. Also that seller has 1000 other different cheap CC Drivers(e.g. 15-36V x XYZ A), 40W,50W, 100W....Downside: never had a meanwell, but with These Drivers Forget about listening to Radio near them (id guess thats true for all cheap Drivers, if not also for more expensive ones). I think i read that you would have to take some extra capacitor implementing measures to avoid that EMI, but i dont care

 

[greenco]

With my HP power supply. The BIAS knob pops out and inside is a time delay fuse. Replaced that and everything works again. I feel comfortable that the power supply is 100% working again. I will work on getting some leds now.

I am still undecided with the Vero 29 or 18. I only lean towards the 18 because I can actually get stand alone drivers for them. I do not want to run the HP permanently. Have you had any luck finding drivers that are more suitable for the Vero 29?

 

[smokey the cat]

Hey thanks Pico, MrFlux and Lax123 - great to get some advice from the peeps who have a bit more experience running this gear.

MrFlux - .
I had been through all of the damn data sheets and hadn't seen anything regarding parallel being banned. It isn't easy to find on the Vero website - I ended up googling it which linked me to the application notes, which are on the Vero website.
Here's the guide to Vero's electrical drive considerations http://www.bridgelux.com/wp-content/uploads/2013/10/AN32-Vero-Series-Electrical-Drive-Considerations.pdf - gets interesting around page 5

The light, or luminous flux, emitted by the LED Array is dependent upon the forward current applied across the junction. At a fixed voltage the current flowing through the devices can vary dramatically depending on the forward voltage of the individual LED Array....
Another array, even from the same production lot could have a different I-V characteristic (curve position). Obviously the light output from a single luminaire using a constant voltage driver could be dramatically different than that of a nearby luminaire also with an equivalent constant voltage driver. This is generally not very desirable.


It is for this reason that Bridgelux recommends against driving LED Arrays with constant voltage sources or connecting multiple LED Arrays in parallel

Maybe might still be OK in terms of "yes it will work", but it sounds like the output could be wildly different. PITA.


I'm beginning to come to the conclusion that Vero isnt gonna be ideal for my micro cab. The drive requirements are just too out of the ordinary to easily find decent drivers from the usual suspects. Thanks for the Ebay links especially PICO - I'd love to find the room for a decent DC power supply, but the size is really off putting. I'm not sure they'd really fit easily in my grow-robe. Gotta admit the fact they're active is also a slight bummer.


For me I think an easier path is going to involve dimmable meanwell and a bunch of single cree emitters, or even cheap osram WW.

Back to the drawing board...

 

[lax123]

you can run them in parallel but its not as simple as just that, you Need to implement Additional circuitry e.g. current mirror with shutdown on fail n stuff

 

[algrow12]

Im in need of some help making a DIY light. Its just for a pc grow I have been looking at leds for a while now. The pc is 8"w x 24"L x 20"T. I dont think I need more then say 50w of a mix of 2700k and 5000k with maybe some far red. Ive looked at the Vero 10 thur 29.
My questions are
1 How many leds to get and what colors
2 which cheap driver or divers to get
3 Maybe a little help putting it all together

 

[lax123]

e.g.: http://www.ebay.com/itm/Waterproof-Constant-Current-10-18x3W-LED-Driver-AC85-265V-Output-DC36-75V-680mA-/261147686300?pt=LH_DefaultDomain_0&hash=item3ccd9d759c this Driver for 3x 2700k, 1x 5000k Vero10-> 77W....you Need 2 Drivers each connected to 2 vero in series. Get a thread drill as you want to screw them to the heatsink

 

[Mechmike]

The Vero is an excellent choice. I would use the Vero 13 and drive it at 300ma. The reasons for under driving them is that they are more efficient (lumen/watt) at lower amperages and they make less heat as well. Here is the vero13 data sheet. http://www.bridgelux.com/wp-content/uploads/2013/10/DS31-Vero-13-Datasheet-2013.07.18.pdf The 70cri 5000k makes about 1500 lumens at 350ma and the 80cri 2700k makes about 1250 lumens. When driven at 350ma they use 11 watts each. I think your choice of colors is good. I would recommend using 2 of the 5000k and 1 of the 2700k and drive them with a driver like this. http://www.ebay.com/itm/Constant-Current-Driver-for-25-36pcs-1W-Hi-Power-LED-AC85-265Vto-DC85-128V-300mA-/321153489743?pt=LH_DefaultDomain_0&hash=item4ac63d5b4f
To get the deep red and 470nm peaks you could round it out with a couple of these. http://www.ebay.com/itm/5pcs-lot-10W-Red-660nm-Blue-470nm-Hybrid-Led-Plant-Grow-Led-Chip-/310747432634?pt=US_Hydroponics&hash=item4859fd86ba
You would need a lower voltage range driver unless you use 3 or 4 of these on the driver I suggested for the Veros.

The Veros alone will make close to 4000 lumens of high par light which is way more usable light than 2 2' t-5s for about 33 watts and that's without adding the red/blue chips.

Adding 2 of the red/blue chips would give you a 50 watt light.

You will need to cool those chips. Heatsink usa is the place for heat sinks. http://www.heatsinkusa.com/

 

[lax123]

Hi mechmike, why would you rather go for more blue (5000k) than red (2700k), thought lots of red is important for flower

 

[Mechmike]

The 5000k has pretty good spectral coverage with a real nice peak at 450nm and has some red although not enough for flower IMHO. That's where the 2700k balances it. When the 660/470 chips are added all of the major peaks get covered. Apachetech makes lights that are heavy on the 5000k and they work pretty well. They use red in most configs although they don't use deep red in any, only 630nm. If I were only running 5000k and 2700k chips I would probably try to use an equal number of each but given the option of adding deep red and 470nm blue at an 8:1 ratio I would use 2, 5000k; 1, 2700k; and 2 red/blue chips.

 

[MrFlux]

About the 2 cool : 1 warm ratio, I really believe this is not optimal. Apachetech uses a 2 cool : '1 extremely efficient red' ratio. This makes a great difference. Or to put it in spectrum pictures, this is 2 cool white vero's with one warm white (had to use 3000K for the warm white as the 2700K spectrum is not available):

It is to heavy on the blue. For 2700K it would be slightly better but still. For reference here is the apachetech flower spectrum:


Using two warms whites for every cool white would give a much nicer spectrum:

With 2700K it would shift a bit further to less blue and more red, but there should still be plenty of blue.

 

[lax123]

yea id have suggested 2:1 too, but then it would not work with the Driver i suggested as you Need to connect 2 cobs to one Driver to fullfill Minimum V and not to exceed max allowed V. so maybe 2x2700K 1x5000k and maybe 1x something inbetween

 

[MrFlux]

3x2700K or 3x3000K would all be fine. More critical would be the mixing of the light, as Pico has found out. To get better mixing the smaller COBs come in handy. Plus the smaller COBs can use high voltage low current drivers which are generally a bit more efficient than high current drivers.

 

[lax123]

critical would be the mixing of the light, as Pico has found out.

sometimes you dont Need to test something to know whats going to happen

 

[guod]

for adjustable color temperatures and good mixing of light...

[h=2]Tiger Zenigata[/h]http://www.sharpleds.com/tigerzenigata.html