DIY LED - Group Buy

[mason dixon]

Originally Posted by Bryan

I have used the 3w blue leds and they work well, but I don't have any Royal Blues to compare with, but there is some info on nano-reef's that the two are almost identical. I am using the Sure drivers, cheap and seem to work well, but do get quite warm when run at close to capacity.

the leds are on a nano reef so just using a 24v laptop powersupply. The sure drivers are quite forgiving for voltage and you have a wide range depending on number of LEDS used.

http://cgi.ebay.com/3w-LED-Driver-MB...item3a6442f9f3

I'm new to leds's....what is the advantage of running those small 3w drivers(I'm assuming one per led?) over something like this this?

[Bryan]

Well, they can run up to 8 LEDs on each driver. From the bottom of the Ebay page is a link to the datasheet, which describes the specs and voltage required for the amount of LEDS used. You will need to provide a PWM input for dimming. A simple 555 timer can take care of that.

[mason dixon]

Thanks, I was thinking that can't be right but I had to ask since I'm such a noob.

Will 1 24v laptop pwm be enough for 72 led's?

[sphelps]

Originally Posted by mason dixon

Thanks, I was thinking that can't be right but I had to ask since I'm such a noob.

Will 1 24v laptop pwm be enough for 72 led's?

Probably not but it depends on the wattage of the power supply, how many watts or amps is it rated for?

For 72 LEDs you'll need at least 200W which I believe is much more than the average laptop requires. You can buy other power supplies that run at 24V at much higher wattage than a laptop supply. I would go larger to the range of 300-350 W encase you ever wanted to add more LEDs.

[StirCrazy]

for a power supply you don't want to go by watts. while this can work it is much easier and safer to go with a constant curent output. so figure out what current you want to run at (700mA or 1000mA) then get one that has enough voltage to handle the amount of LEDs. you want to run your blues on a different power than your whites

here is an example of one of the better drivers to come out laitly
http://www.nanotuners.com/product_in...roducts_id=754

this is a 64 top 114 volt driver at 1050mA you can get them bigger or smaller.

Steve

[sphelps]

Steve are you talking about a power supply or driver? If the driver runs off 120VAC then obviously you don't need a power supply but some drivers already discussed require a lower voltage DC supply so you need a separate power supply. The driver must be constant current but the power supply only needs to have enough power (watts) to run the driver(s). The voltage of the supply is also important and dependent on how many LEDs are in each array for each driver.

[StirCrazy]

Originally Posted by sphelps

Steve are you talking about a power supply or driver? If the driver runs off 120VAC then obviously you don't need a power supply but some drivers already discussed require a lower voltage DC supply so you need a separate power supply. The driver must be constant current but the power supply only needs to have enough power (watts) to run the driver(s). The voltage of the supply is also important and dependent on how many LEDs are in each array for each driver.

I am tazlking about a driver and power supply in one unit. I have looked at both ways and find no advantage to one over the other aside from a all in one unit "can" under the right situations be cheeper and the end result is usaly much cleaner.

the units I was talking about will self adjust to a requirment between 64 and 114 volts. the TR are a little more cost wise than meanwell but they have the higher capacity ie. this one will handle about 33 LEDs (max), they dont have the inrush problem that the mean wells have. as well as they also have a built in 10V reference voltage so for manual dimming all that is required is a pot.

heres a link to the info sheet on them http://www.thomasresearchproducts.co...2001-31-11.pdf


Steve

[Bryan]

Originally Posted by StirCrazy

here is an example of one of the better drivers to come out laitly
http://www.nanotuners.com/product_in...roducts_id=754

this is a 64 top 114 volt driver at 1050mA you can get them bigger or smaller.

Steve

I would recommend unless you are experienced working/designing around electricity stick with a lower voltage, 65-115 dc can be dangerous. You may want to look at a 24vdc 10-15 amp power supply, and use multiple drivers in parallel.

[StirCrazy]

Originally Posted by Bryan

I would recommend unless you are experienced working/designing around electricity stick with a lower voltage, 65-115 dc can be dangerous. You may want to look at a 24vdc 10-15 amp power supply, and use multiple drivers in parallel.

anyone who is considering building a LED fixture should not be unexperienced with electricity in the first place. besides as little as 35Vdc can give you a hell of a jolt, more so if the power supply allows for higher currents, the TR does have short circuit protection which should tell you if something is wrong the first time you plug it in

think about what were doing here. we're soldering a ton of wires to pads on a hunk of aluminum and suspending it over a tank of water... what is safe about this in the first place? as with any DIY involving electricity, this is not for some one who doesn't feel confident working with electricity and there skills to do so.

I am actually testing a couple ways to electrically isolate everything after it is together, for a few reasons. one - so humidity can condensate and make a water drop shorting out a led to the heat sink, two - so you don't bump a bare wire while your working by the light, and 3 - to prevent corrosion of the solder joints from salt creep and humidity. when I find one I am happy with I'll post it, but so far the liquid electrical tape is looking pretty good.

Steve

[msjboy]

Can you get the following items:
http://reefledlights.com/shop/led-seal/ : this is a spray to protect the welds... by a company called Luxdrive.

Philips LEDs - Rebel ES series.... apparently better than CREE in terms of lighting suitability for corals. nano-box-reef.com/ uses them.

msjboy