Safe LED power on the cheap

Growroom Design
#1

Hi Everyone,

I have seen a number of builds now, both on the web and in person that have made my hair stand on end. Many people don’t seem to realise that the drivers they are using can deliver up to 450 volts @ 3Amps and this is MORE than enough to kill you stone dead. As in dead before you hit the floor. To make things much worse, a lot of the DIY lights have aluminium frames and often people simply poke the wires into the connectors. All it takes is a stray wire touching the light frame and next time you touch it your ass is grass. If you don’t know electrics, stay the f away*** from high voltage.
Anyway, this is a low voltage, low risk and cheap way of avoiding the above risks. As always, practice safe working when dealing with anything electricity.

  • First acquire an Xbox 360 PSU, there are a high quality reliable DC powers supply of 12V DC with over 10A and can be found cheap or free if you scrounge.

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  • Get some TE636 DC-DC 250W 10A Constant Current Step-up Mobile Power Supply Driver Modules from eBay. These can be had for a little as $5 if you buy a number and give both adjustable voltage output AND adjustable constant current and they look like this:

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Specifications:
Module: 250W Step-up Module
Module Properties: non-isolated step-up module (BOOST)
Input voltage :8.5-48V
Output voltage: 10-50V (adjustable)
Output Current: 10A (MAX) (Please enhance heat dissipation if more than 6A)
Output constant Current: 0.2-8A (please don’t short the output to adjust the current)
Working frequency: 150KHZ
Conversion efficiency: 96%
Operating Temperature: -40°C to ~ +85°C
Over circuit protection: Yes
Input Reverse Polarity Protection: Yes
Dimension: 70 x 46 x 13mm

  • Remove the end connector of the PSU unit and strip the wires, they will look like this or very similar.Yellow is 12v Positive (+) Black is negative (-). The green and red wire are the activation connector, if you don’t jump these the xbox PSU won’t supply power, ideally you would put a simple 2 pole switch inline here or alternatively a relay etc.

  • Twist the yellow positive wires together and the black neutral wires together. Tin all the wire ends and sleeve it with some shrink wrap, if you cannot solder, it’s about time you learned or just twist it well and either heatshrink or tape it.

  • Cut a plastic terminal block to suit and connect the tinned wires to one side of the block and connect the positive and neutral of the step up driver to the positive and neutral of the psu via the terminal block.

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  • Connect your multi-meter and adjust the output voltage via the module adjustment screw till it reaches the voltage you require for your LED. In my case it was 36V.

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  • The modules by default are supplied set to 1 amp, connect your light, power supply and multi-meter in series , as in the picture. Set your multi-meter to DC amps, and make sure it’s red cable is connected to the amps plug.

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  • Switch your power on, and when you can see use the adjustment screw on the converter module to the constant amps you require. In my case 1.1 amps.

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Done! :sunglasses:

You could comfortably run 3 Samsung 50 watt strips from a single PSU, giving your PSU a bit of headroom so it doesn’t get too hot. It’s feasible that you could run more than one strip per converter module, but I have not tried it. These modules are rated to 250W but if you use them much above 50w I woudl start thinking about a heat-sink for them just to keep them alive longer.

Enjoy!

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#2

Step up and CC? Nice find! :+1:

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#3

Nice write-up!! Plus extra chars…

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#4

Yep, and cheap, these are capable of running a full power COB no problems.

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#5

You can get these rectifiers for 80$ on eBay. https://endless-sphere.com/forums/viewtopic.php?f=2&t=66169&p=995128#p995128
Easy swap between 1000/1800 watts.

1 Like
#6

That’s an awesome find, Eaton are known for decent quality too , one of these and a handful of TE636 DC-DC 250W modules and you have all the safe power needed for at least a mid size tent for a fraction of the price of a decent meanwell PSU.

2 Likes
#7

I hear ya pal.
I solder, do simple wiring jobs and the like but even with your great diy, I don’t have a clue how I’d build one of these.
Here is what my 6000 - 6500k ledmo flood is putting out.
What kinda numbers do you get with a setup like that?

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#8

There’s a lot of 48v options out there that can be hooked up directly. I went with 16 288 v1 qb’s.

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#9

Yep, as I said I have seen some DIY’s that were death traps and I’ hate to see a brother end up in the ground as a result.
The strips I am using are the Samsung FSERIES GEN3 3500K strips, I have a number spare as in my stonedness one night when ordering I got the 1100 mm strips instear of the 500mm and they are tool long to be practical for me. :stuck_out_tongue_closed_eyes:
Theses strips put out around 9000 lumens, so pretty close to the numbers you have with your Ledmo, though the strip is a 3500K, which I thing gives the best mix or flowering and stretch. I find if I run 5000K lights exclusively in veg my indica plants end up so squat that there is hardy any room for branching.

I hear people talking about the lack of light penetration with these strips and it’s true the LUX levels decline rapidly the further away from them more than a COB etc, BUT IMHO, this ‘penetration’ people talk about isn’t all that.
If you think about the the leaves containing the chloroplasts as cells, then if all of your light is emitted from a single point the photons are going to be overwhelming some while missing others. This is why all research points to diffused light being MORE efficient, It would be my guess as more of the chlorplast are receiving their share of the light output and therefore are more efficient at converting the light to sugars and other metabolic outputs.
And really if you want more light penetration, defoliating, tying the plant down or even putting a few strips on the sides/underneath may be an option. The other advantage of these strips is heat, I can put my hand on the back when they are running so less air needs to be circulated to keep things cool.

I plan to do a detailed step by step build of a 25K lumens strip light soon, I am just waiting for some parts to turn up.
Hopefully this will provide enough information for anyone to be able to do it, and do it safely. No weed is worth dying for.
Cheers!

2 Likes
#10

dont think it would work for me … my driver is 230V and i kinda like meanwells 7 year warranty, have already had 2 drivers replaced … cool thread tho

#11

That is exactly why I run hi K for my sativas. Those plants in the pic are 2 monster-clones and a re-veg.
Right now my experiment has a control plant that is under my off-the-shelf=blurple 120watt screw in. It’s a sativa blend and it is aiming for the moon.:waning_crescent_moon:
For my 2x2x4 tents, any bulb array with 3watters gives good results.
But setups like yours are just neat as hell, no dangling bulbs and tons more headmoon.
I’ll be staying tuned.:beer:

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#12

You have fried 2 meanwell drivers? :open_mouth: That would unusual! The MTBF should be at least 50K, are they running at full load constantly?? 80% capacity is the max for reliability in my view, maybe that’s it? In my job I have installed many MW psu’s in some pretty hostile environments and have not seen 2 failures, you must be working them real hard bro :slight_smile:

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#13

the first one lasted a year or something running 24/0 at ~50% then 12/12 at 100% but i think the second one was just faulty - it was my replacement and blew within 2 weeks of getting it

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#14

What 1350 watt drivers are these? Not Mean Wells. Mean Well doesn’t make an LED driver (in the HLG series anyway) over 600 watts. Most diy LED lighting rigs use 250-500 watts per lamp array.

If you use a step-up convertor to boost the voltage from the Xbox PSU, which you say is a 12volt, 10amp (120 watt) power supply, to boost the output to 36v at 1.1A, you get a 40w driver. 80 watts less than you began with, but ok, you’ve got the power configuration you need.

An Xbox PSU goes for about $21 on Ebay. The boost convertor is $5. Let’s say you have the rest lying around, that’s $26 plus shipping and your time to build a jerry-rigged driver with a non-water resistant power source that is completely dependent on a cheap, exposed, generic component.

Or you could buy a 36v, 1.1A HLG-40H-36A Mean Well driver for $28 and get a fully integrated, fully waterproof, dimmable CC/CV LED power supply with a 7 year warranty. What am I missing?

If you are going to try this with an old PSU you have lying around, tape up the convertor or mount it in a small project box to keep it at least a bit dry and unmolested.

3 Likes
#15

Yeah, unfortunately meanwell are not there yet with their drivers. Inventronics was the drivers I was thinking of from my experience here. In any case, even 1.5 amps at 350V is well and truly lethal.

My ‘how to’ was not intended to be a full build, else I would have explained things in a lot more detail and completed it, it was simply to show a way to recycle power sources you may already have access to on the cheap, as you note it could be a PC PSU OR in my case currently a 600w Dell server PSU.

The Xbox PSU is 150W, so it’s really 12 amps and I believe also come in a 200w version. Also MOST decommissioned servers will also have at least one PSU that are at LEAST as good quality wise as the $25 driver you linked to.
The actual source of your power in this example is really an example, it just happens to be that these ones can be found at garage sales, flea markets more or less for free.

I run Osram Optotronic drivers rather than meanwell when I just want to power a single strip, I can pick them up for $15 but it’s horses for courses really.

I think there maybe a bit you are missing here. For example in this configuration it is possible to run 2 strips off a single PSU, with a boost converter each or in parallel, if you wanted to run the PSU at full clip you could run 3 strips off one PSU for 27K lumens.

Also let’s say you ‘jerry-rig’ a 600w dell server power supply, You can then just use the modules to distribute the power to the strips. If one fails, it’s one strip, not all of your lights. IF you are really paranoid about a failure, then you can rig 2 PSUs to run in parallel, so long as you don’t use more than half the load you have redundancy, or you could use four and and have 1200 watts or redundant quality power. Use a single driver and you are screwed if EITHER the driver OR one of the in series COB’s or strips fail. It provides a flexibility/redundancy that a single driver rigged in series doesn’t and it’s all at a safe low voltage.

I run these boost converters potted in resin on my boat for all my cabin and deck lighting, I’ve the modules up so I can swap them out easily and carry 2 spares precisely because they are generic, happily in 2 years have not needed one, and most grow rooms are going to be less hostile than my boat I would think. And at 1-3 amps they are hardly working at all.

Also, the example was in no way completed, as in it was little more than a bare breadboard example and of course the parts would normally be housed and insulated in some way. This literally took me less than 15 mins. l’ll do a proper full build shortly. Cheers.

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#16

What about using a 300W or 400W MiniITX or TFX PSU? They are a bit larger than a XBox PSU, but are small compared to a normal PC PSU.

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#17

Perfect. This is what you need to do to the 20 pin molex on an ATX supply, which are common as muck, and can have some serious output, just put it outside the tent. The mini ITX will be a variation on this.

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#18

So I would attach the 12v (yellow) to the red lead of the step up module?

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#19

Just saying if you Earth your light builds then you won’t be at such risk of death :v::+1:

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#20

Yep that’s it and black to the black (neutral). For the newer ATX PSU you may need the resistor to be up to 20W or 10% of the rated power for the larger 600W+ PSU’s to get it to start, thats not ideal so older pc psu’s may be the best bet. Also the Pwr_Ok circuit is optional in this diagram. . This is why Dell server PSU’s are ideal, one jumper lead and they are good to go and they are plentiful, good quality and have lots of power.

1 Like