DIY LED lighting?

[GreenNeedle]

I suppose that's the hardest part to work out. The plan was to make a board to fix into the hood ceiling and then attach the bent aluminium strips to this and screw the whole thing into the hood so the LEDs were the same distance from the water as the current fluorescents.

That means the following dimensions.

Actual tank (inside measurements) are:
Length = 790mm
Depth = 340mm
Substrate level (at deepest point) to water Level = 355mm
current distance of lights (lowest point) to water level = 100mm

I assume you are assessing the angle of spread from the LED as to wether it would work as well per watt as T5HO with v good reflector?

Here is the modified plan:


AC

 

[SteveyG]

You should get quite a good spread of light with the LEDs spaced evenly across the hood with that size tank and that number of LEDs. If you ever needed higher intensity, it would not be difficult to add further LEDs at the diagonals between the existing LEDs.

 

[GreenNeedle]

How much brighter do you think this LED setup at full would be than it's T5HO equivalent? Don't want to go too highlight. lol

One other reason I am sticking to the 3W is the ease of soldering but also that they are £40 for 20 off ebay inc shipping.

AC

 

[SteveyG]

It's difficult to say. You should be looking at similar light outputs to T5, perhaps even better.

Got a link to the auction for the LEDs?

 

[GreenNeedle]

http://cgi.ebay.co.uk/20x-White-High-Po ... m153.l1262

I have sent him a message asking for the K but I am guessing tey are 5500K at the mo

AC

 

[GreenNeedle]

These could bring the price of twenty down to £36!!!

http://cgi.ebay.co.uk/ws/eBayISAPI.dll? ... :IT&ih=015

AC

 

[Ed Seeley]

That plan's looking good Andy. I'm thinking I need to have a go at one of these over the Christmas holidays maybe. One thing that would really help me is if we could sort of get a comprehensive shopping list of ideal requirements here between us. All the sparkies and experienced people on here would be able to help us with that I am sure.

The only thing that's putting me off slightly is that the guy on the other forum had all of his burn out! Why did this happen? Did he run too much current through them or was it the wrong type of power source? Would it be better to have multiple smaller power unit driving 3 LEDs like Andy's planning or a larger, more expensive but better regulated/designed power source driving more LEDs?

I suppose what I'm saying is what is the ideal way of building an LED light?

 

[GreenNeedle]

I'm doing it this way as it leaves room for error (mistake on one and only 3 LEDs at risk) plus I can get the sun moving across the tank with these individual timers without any knowledge of a controller to do it.

Apparently the ones on the other thread burnt out due to not having current controllers

The list I have at present is:
aluminium bar to cut and bend for each LEDS mount

2 sheets of perspex the internal measurements of my hood. 1 to rest on the hood feet seperating light from water and also stopping the air from the fans assisting evaporation. The other to be the main mount which will hold the aluminium mounts cut to my fixed section and flap dimensions (the front of each series is going on the flap!!!)

wire which I have no idea which type or where to get it, nor what it is called.

20 x 3W LEDs (5 spare)
http://cgi.ebay.co.uk/ws/eBayISAPI.dll? ... :IT&ih=015

5 x current controllers for each series of 3
http://cgi.ebay.co.uk/3W-Power-LED-Driv ... dZViewItem

16 x heat sinks for the rear side of each mount (1 spare)
http://cgi.ebay.co.uk/ws/eBayISAPI.dll? ... :IT&ih=022

2 x double fans:
http://cgi.ebay.co.uk/ws/eBayISAPI.dll? ... :IT&ih=002


Plus 5 x 12V adaptors and 5 x timers

Don't think I've missed anything 😉 bzzzzzzzzz 🙄 😳

AC

 

[SteveyG]

Ed: The reason they burnt out is that LEDs do not work like incandescent lamps. LEDs do not conduct until they reach a threshold voltage. There may then be only a 0.5V range between 0 and 100% brightness, and any higher will cause the LED to overheat. If you control the current into an LED, you can easily control the brightness and also limit the maximum current and hence prevent any damage to the LED. The LED then doesn't succumb to supply voltage variances because the constant current driver adjusts it's duty cycle accordingly.

 

[JamesM]

Those fans are mega loud guys.

 

[GreenNeedle]

James - how do you power yours?

For example I was complaining the other day about the loudness of mine whilst reading MrTester's thread with him saying he couldn't hear them.

Then I turned the voltage down from 12V to 6V and then to 4.5V and I couldn't hear them 🙂 At 6 they are quiet and at 4.5V they are almost silent

So rather than have 1 fan running at 12V you can run 2 at 6 or 3 at 4.5V which solves the noise issue.

The lower speed doesn't matter too much. We're not after gale force, just a light breeze flowing from in from one end and out of the other.

AC

 

[JamesM]

I used to use them a lot when I modded pc's, so I ran them at 12v. I always went back to 120mm fans as they're super silent.

I have trouble remembering what I did last week, let alone 20 years ago at school electronics, so I'm looking forward to this build a lot 🙂 Don't like the idea of 5 power supplies though...

 

[GreenNeedle]

5 power supplies in terms of plugs but they won't be drawing that much power really. there will only be one cable outer coming from the hood though with all the rest fed through it and then seperating again within the cabinet. Probs use one of those round comb binder zip up type of cable tidys. (They are £1 for 2m in Poundland 😉)

The fans I currently have on the hood are 40mm and were super noisy at 12V. Think of an old PC booting up, then multiply that by 2. Now at 4.5W they are super silent. Powerhead is noisier. lol

AC

 

[SteveyG]

James is right - If you can, look at getting the largest fan you can. Perhaps mount it to the top of the hood rather than the side as the big fans are a lot quieter and if you throttle down the voltage they can be silent.

 

[JamesM]

5 Power supplies is still an issue. I have enough extension sockets running around my house, I don't need any more :? If someone can come up with a 240v conversion however...

 

[SteveyG]

Don't worry - mine will be one plug only 🙂

 

[JamesM]

Don't worry - mine will be one plug only 🙂

Brilliant! Looking forward to seeing you put it together 🙂

 

[GreenNeedle]

Annoyingly unknowledgable again but.....

....With the current controller....if it is a 12V and requires 1.5V for itself that leaves 10.5 to power the LEDs. Does that mean that if an LED says 3.6V and my idea being a series of 3 that it won't run on 3.5V (one third of 10.5)?

Will it not work at all, or will it deteriorate quicker or....?

AC

 

[SteveyG]

You'll be right on the limit of not being able to get full brightness from the LEDs. It would be a bit more comfortable to have more headroom by using a 15V or 18V PSU, but if you already have some power supplies going for free, you can always see how well it works with those first. You won't damage anything.

 

[GreenNeedle]

I've just costed this little project up and WOW I underestimated it. lol

So far I get:
Perspex for group mount and condensation barrier - £15 from Wickes (huge sheet but smallest they have)
Aluminium bar for individual mounts - £3 from B&Q
Double Cooling Fans x 4 (8 fans!!!) - £10 off ebay (already bought)
3W LEDs x 20 - £36 off ebay
Current Controllers/Drivers x 5 - £27 off ebay (already bought)
Heatsink x 16 - £5 off ebay (already bought)
Thermal tape - £5 from Maplins

Thats £101 without the price of timers and DC plugs which I already had!!!!

Also doesn't include wire. Which wire am I looking for? Will bell wire do?

Finally the 5 adaptors I have say the following on them. will they all be OK to use?
12V 800Ma
3V - 12V - Rating up to 1200Ma
12V 1400Ma
3V - 12V 800Ma
13.5V - 1000Ma

Can you tell I'm a little excited 😉

AC
AC