Diy Led Lights - Not Really The Correct Way...

[Neo8223]

Hi All
 
I love tinkering around with DIY, but as I still live at home, my dad doesn't like the idea of keeping lights on the fish tank on all the time. As it is, i only have 0.8WPG which just isnt enough. I did a bit of research on the net and everyone is banging on about LED lights and that they are cheaper to run, so I thought i'd give it a go.
 
I made an initial prototype out of 5v LED's which were the correct colour temperature. We couldnt get the full power out of them as the transformer was maxed out, so we tried a Li-Po battery at 6.2v. Turns out its 5v for a reason and for 2 days of painstakingly long soldering, we threw it in the bin. (they went pop) Oh well, £2 down the drain.
http/www.ebay.co.uk/itm/110936128110?var=410131514220&ssPageName=STRK:MEWNX:IT&_trksid=p3984.m1497.l2649
 
Enter my next prototype. Using these for white:
 
http/www.ebay.co.uk/itm/270853683079?var=570052652105&ssPageName=STRK:MEWNX:IT&_trksid=p3984.m1497.l2649
 
these for blue:
 
http/www.ebay.co.uk/itm/270853683079?var=570043836590&ssPageName=STRK:MEWNX:IT&_trksid=p3984.m1497.l2649
 
I used these colours it was recomended to me by some guy at a fish shop. (highly technical NASA quality control). So, the good thing is that they are REALLY easy to set up and after 2 evenings as opposed to 2 days, I had a working model.
 
Heres what it looked like after. (I mixed PVA glue with water to seal the wood)
 

 
Nice and neat eh! 
 
So I then plugged it up to a watt meter. 
 
Wattage usage @240v = 42w for 10m
 
We tested it with a caravan 12v battery incase there wasnt enough current. It didnt look any brighter! (Again, extremely scientific in my approach)
 

 
One quick check that the lights were working and we are ready to go.
 
Now in order to do a fair test, and to show you how the light looks, I took out my SLR and a tripod and set it to full manual.
 
The exposure was:
 
ISO 400, F 4.5, exposure 0.8 seconds for both the below pics.
 
So here is the benchmark. 2x30w bulbs at 0.8wpg
 

 
Here's the results
 

 
Annoyingly it looks like the second one is brighter. To the naked eye it is not.
 
Now here's the million dollar question. What one will promote plant growth more. So, if we look at the radiator on the left, it has much more blue, than with the flourescent tube. Now, at this point, i'm really wishing I didnt listen to the guy at the fish shop as it seems that aquatic plants prefer 2800k. Marine on the other hand prefer a high Kelvin.
 

 
So, I considered this a constructive fail. Back to the drawing board for next months re-attempt using more tried and tested methods.
 
Any tips/comments welcome. Constructive only please. and Yes, my tank looks awful, yes that CO2 ladder is useless too, and yes, i've bought a new one but i'm waiting for delivery of another ceramic diffuser and finally yes, i probably should have moved that magnet in the middle of the tank.

 

[DrRob]

Interesting info on the Kelvin that plants prefer. Got any references?
 
From what I've managed to read, aquatic plants prefer spikes in the blue and red ranges, but most algae strongly prefers the red end of the spectrum, so strong blue lights will promote plants above algae, which is what I want. Plus I think it looks nice, so I tend to tolerate lower intensity lighting as it appears brighter per watt to my eyes, so I can put less energy into the tank, allowing a better balance.
 
So, overall, I deliberately go for the sort of spectrum that you've got there.

 

[Neo8223]

Hi DrRob Pleased you like it! I wonder if its worth trying my DIY light for a few days once the plants that I just put in begin to grow. That way I know i have a benchmark to work from
 
I went on a few sites including the Hagen website and compared bulbs. The below is for a flora-GLO. I presume that if the colour temp output is predominantly 2800k, it would be the more warm white/red spectrum, which my colours clearly do not use. Below is a snippet for the Flora-Glo bulbs. (i have 2 of these in the tank which is why it must appear a bit yellow)
 
The Flora-GLO T8, 30 W linear fluorescent aquarium bulb delivers a strong photosynthetic spectrum that is ideal for planted aquariums and terrariums. With a color temperature of 2800K, this normal output fluorescent bulb is strongly recommended for use in planted aquariums to ensure a broad red and blue spectral presence, which is ideal for stimulating strong plant growth. The bulb fits all suitable standard and electronic ballasts. Flora-GLO is recommended in combination with Life-GLO and Power-GLO bulbs. Size: 91 cm (36 in).

 

[dgwebster]

The efficiency of the LED you have here are not like the systems you see for hundreds available commercially. These use cree xp-e and better LED and oddly, you are about watt for watt but get the ability to be extremely picky over your colour range.

As above, your colour range is right for promoting fish tank plant growth. In tubes though its typically 2:1 on the blue, for led, 3:1 is probably good enough, maybe even 5:1.

 

[Neo8223]

Just google'd cree xp-e good find!
 
Hmmn, so if i have 1:1 on the blue, i should imagine its even more in favour of the plants? Below is a pic that I took earlier just of the blue lights.
 

 

[dgwebster]

Not really, the spectrum isn't full enough (from what I know). What you want to do is emulate briht daylight with blue skies.

 

[Neo8223]

Hmmn, I suddenly have a cunning plan. I'll get an extra 5m length of bright day light and remove 2 strips of blue in place. which will leave me on an 8:3 ratio. (2.67:1)
 
Although it will probably end up using almost the same 60W as my other light unit, I should imagine that it will output more lumen's?
 
Stay tuned!

 

[ian_m]

My mate used some of these self adhesive 12V LED strips from Ebay. Now not using them back to ye olde T8 tubes, which last.
 
Issues were:
- Not as bright as advertised, had to add some more to his initial design to get anywhere near the same brightness as the original T8 tubes. Still never got as bright as T8 tubes, according to his eyes.
- The self adhesive bit failed after a while, the glue going hard and falling off. Either exposure to the LED light ruined it or water got in. But had to re-glue using a proper glue eg contact adhesive.
- Water got in and started corroding along the internal tracking. Copper carbonate "fuzz" could be seen on the internal PCB, working its way along the internal PCB. This occurred at the end of the strips, despite sealing with silicone. It appeared the tanks condensation water tracked down between the wires and silicone and into the end of the LED tape. Copper is very toxic in the aquarium, especially water soluble copper carbonate. Parts ber billion will kill invertebrates.
- After about 9 months some of the LED's were noticeably dimmer than the others. The rubber/plastic around the LED had gone yellow/brown clearly being effected by the light. Some of the LED's had failed completely in groups of 3.
 
Anyway back to working T8 tubes until next money saving idea.

 

[dgwebster]

The 5258SMDs and similar are not really comparable to the xp-e and later cree LED SMDs. It is also the difference between energy saving and not energy saving. Using suitable LEDs for a fish tank are not likely to save you energy, but you do get a more specific spectrum choice and if you want low light tech, you can opt for less, meaning for the same luminosity of a 30W tube, it might cost you 24W.

 

[Neo8223]

Hi All
 
So Mk II is on its way. This time around, im using high powered LED's 
 
Specifically:
 
2 x 10W 5700-6300K LED's - http/www.ebay.co.uk/itm/121225179735?ssPageName=STRK:MEWNX:IT&_trksid=p3984.m1497.l2649
1 x 10W 10000K LED - http/www.ebay.co.uk/itm/330793781106?ssPageName=STRK:MEWNX:IT&_trksid=p3984.m1497.l2649
4 x 3W 15000K LED's - http/www.ebay.co.uk/itm/390733376980?ssPageName=STRK:MEWNX:IT&_trksid=p3984.m1497.l2649
 
I tested out one of the 5700K LEDS without a driver or heatsink for 10 seconds and they give off an incredible amount of heat and I had to wear 3 pairs of sunglasses to be able to see the light without burning out my eyes
 
Therefore lesson 1 and 2 in no particular order:
 
1) Don't be an idiot  Always operate with the correct driver
2) Always use a heatsink
 
Working in the IT team provided me with ample spare heatsinks. Im using one off an old Dell optiplex GX620 for the 10 W LEDS. They are the same as the dell optiplex 745
 
For reference, heres what it looks like on ebay. - http/www.ebay.com/itm/Dell-Y1851-USFF-Heatsink-Optiplex-GX520-GX620-740-745-755-USFF-models-Excellent-/390626194166
 
I then researched into what id need for the 3W LEDS. Fortunately in the same Dell optiplex GX 620's they have smaller heatsinks for the southbridge controllers (pat yourself on the back if you know what that is) which will fulfill the heat dissipation on the 3W LEDS perfectly. (i hope) 
 
Ill take a pic of this later on as i cant find on ebay or web.
 
The dimensions are still a limitation for me, these are 95 L x 12.5 W x 6.5 H
After taking into consideration the Acrylic which is 0.5cm, I have a ceiling of 6cm to work with.
 
So after re-installing office visio 2007, i got to the computer and started some CAD to make sure it all fits!
 
Below is lid design
Inside the lid (excluding fans)
Side view (including fans)
 

 
 
I have not decided what LED drivers i want, however, as i would only need 4 in total, i might just buy separate to avoid problems if one LED burns out, so i have not incorporated it in the design.
 
The fans are super powerful, and quite noisy. Im hooking them up to a thermostat control switch which works off 12v to use them only when the temperature goes above 50c (which im sure will happen) I got the fans off yet again, the same dell GX620's (2 per computer) and rigged them up to this lovely piece of kit which i have tested and working.
 
Thermostat controller - http/www.ebay.co.uk/itm/301058693629?ssPageName=STRK:MEWNX:IT&_trksid=p3984.m1497.l2649
Dell Fans - http/www.ebay.co.uk/itm/Dell-Fan-Optiplex-GX620-SX280-USFF-Fan-Shroud-OU8679-/250721748360?hash=item3a602e4588
 
My next step is to see what is out there to add a heat failsafe on the light circuit. This will
 
1) turn off the lights if the rig goes above 100c. The fans will be on their own circuit as a failsafe.
2) Sound a siren which will be loud enough to wake the dead, or in my case wake me up from my deep sleep.
 
My DIY circuitry skills are pretty useless, so heres where i could do with some help here. I need another thermostat controller to shut off the light system and activate a the siren which will either:
 
1) work off 240 V(preferably) then I buy 4 240-12v 10W drivers
2) Work off 12 V then I buy 1 transformer and 4 12v - 12v 10 W drivers
3) Im open to suggestions.
 
I guess I could use another thermostat controller that Im using for the fans, but then use a component or a tri-state logic gate (if im correct) to control the lighting circuit and then put the LED before the logic gate in its own circuit but i have no idea if that is even correct.

 

[Neo8223]

So I worked out the rest of what i'd need, all circuits and everything comes to just over £50
 
I read more about relays so I now know what needs doing. 
 
Heres the entire circuit I had to be creative with some of the symbols as visio didnt have a relay symbol( used a switch/thermister and a relay contact), nor siren (used a bell)
 

 
Heres how it works
 
There are 2 temperature sensors
1 manages the fans - after 40c the fans turn on
the other manages the lights. If the temperature gets over 80c, the light circuit cuts and the siren goes off (relay 2 and relay 3) sending my whole household into a panic.
If for some strange reason, there is no 12v present, without relay 4, the circuit would still work. Therefore the lighting circuit is defunct.
 
Next update will be when i get more components.

 

[ian_m]

I built something like you are describing using these 10W LED's. Were initially impressive, but learnt my lesson why one buys proper LED's (Cree) and proper drivers.
 

This is what happens eventually the LED arrays. One starts failing (picture taken through filter), eventually whole column fails, then all LED's fail. They were being driven by correct current drivers, in fact no where near their maximum rated current. LED arrays were all suitably heat sinked as well.

Considering T5 tubes now.

 

[Neo8223]

I built something like you are describing using these 10W LED's. Were initially impressive, but learnt my lesson why one buys proper LED's (Cree) and proper drivers.
 

This is what happens eventually the LED arrays. One starts failing (picture taken through filter), eventually whole column fails, then all LED's fail. They were being driven by correct current drivers, in fact no where near their maximum rated current. LED arrays were all suitably heat sinked as well.

Considering T5 tubes now.

Good to know! Thanks for the input. Ill watch out for it. I think if i were to repeat this experiment for mk3, id stick to 3w led's like most people seem to do. The amount of lumens they produce compared to these big led's is almost tripple for the same power.
 
I made a bit of a mistake with the 3w/3v leds. I actually need to buy 16 now, which I have done. This is because:
 
I bought a 12W 12V driver for it.
 
The rule is, connect in series, you multiply the voltage, wattage stays the same
 
connect in parallel, voltage stays the same, wattage is multiplied.
 
Therefore, I will now have 16 3W leds, running 4 sets of 4, for my 12w. They can also run cooler too, so im just going to use 4 per big heat sink. Each unit in theory should produce the same lumens as my main 10W LEDS!

 

[ian_m]

You drive LED's, especially these chips arrays from constant current not voltage. You will quickly destroy them on constant voltage.

The ones you quote are 700mA, 900mA & 1000mA current so you will need corresponding constant current drivers (or drive all at 700mA). They must be connected on series so same current goes through both. The output voltage it quotes is the maximum output it will drive when connecting more than one LED, ie if your LED's quote 9-12V @ 900mA then a 900mA 40V driver will only be able to drive 3 LEDs in series, giving 27-36V output to drive 900mA through LEDs.
 
Just search Ebay for "led driver 900ma" to get suitable drivers.
 
The Cree LED I bought 10W cost 15 pounds & Cree driver 12 pound was much brighter, lasted for ever....well still got it unlike Ebay specials which got binned as they all eventually failed, including one LED driver.

Project didn't proceed, beyond initial test, as I had real issues waterproofing everything despite sealing using loads of silicone, water still got in and corroded contacts.

Also, in my opinion 10W was too powerful, like you said most people used more off of 3W LED's to get a better light spread.

Lesson learnt....back to T5 tubes. (actually more energy efficient at 114 lm/W compared to Cree 90 Lm/W).

 

[Neo8223]

I wish i read this 2 days ago lol. I just bought everything. Oh well im doing this more for learning so lesson learned. MkIII might have to be next month.

Fortunately the drivers i bought were of that spec, but they are also cheap so i should imagine they will suffer the same concequence. Im not overly worried about moisture as it is going into an already sealed container. Ill take pics tonight, but although there will be humidity, im thinking there might be a little humidity, there shouldnt be any accumilation of water. If so, i can modify the design to have fan exhaust pipes which i can mould using a plastic strip bender on the intake fan. (Dont care about exit as its exit lol)