BarraCudaTM

If you are talking about efficiency, 1W @350mA and 3W @1000mA, 1W is always more efficient than 3W in terms of lumens per watt. Thus it is not wrong to say that 3x1W will give more lumens than 1x3W. However if you consider the depth of tank than having 1x3W might be better than 3x1W. Light follows the inverse square law, meaning if you double the distance, intensity will be reduced to 25%. Assuming 1W@350mA is 100lm at 1ft distance, at 2ft, it will only be 25lms. Assuming the same LED driven at 1000mA, will be 250% of 100lm = 250lm at 2ft, it will be 62.5%. Thats why for deep tanks, Higher wattage LED is better. If you are having a 1ft height tank then having multiple 1W LEDs is better.

Have you considered using the CREE XPGs? It peaks around 440nm Min 114lm@350mA or min 285lm@1000mA (105lm per watt)

Your previous ratio is ~1.4:1 white to blue ratio. If you change it to P7, that would be ~5.5:1 white to blue ratio. It will appear yellowish ...

Going by yr current blue to white ratio, changing to P7 will shift the color temp more towards BLV10K and lower.

Wow ... so fast and you are upgrading. You are driving it at 700mA per die?

I would agree that having a proper finned heat sink would be the best choice but I would also like to take cost efficiency into consideration. Massive heat sinks costs alot! but if we can compromise performance and costs .. why not? Several issues we need to consider for heat sink selections. 1) Thickness The thicker the heat sink, the better spreading of heat. The main criteria is not to allow localised hot spots on the heat sink. The temperature across the heat sink surface must be able to spread evenly. If a heat sink is too thin, the heat sink area directly behind the LED will be very hot while the rest of the heat sink is only warm. In this case, the heat sink is not effective. Aluminium will expand significantly when heated. This will cause warping and de lamination between LED and heat sink if not rigid enough. Once there is an air gap between the LED and heat sink, the LED will heat up and deteriorate rapidly. 2) Total cooling surface area The higher the surface area available, the better radiation of heat. Finned heat sinks provides more cooling surface area than flat aluminium plates. To compensate for the lower surface area, you simply use a larger piece of aluminium plate. For me, I use a aluminium plate size of 4'X2'. 3) Color Black objects radiate(lose) heat(infrared) much better than shiny objects even though they are of the same temperature. That is the reason why I'm saying most infrared thermometers are not designed to work with shiny surface. Objects emit infrared radiation when heated, a shiny object will emit less infrared radiation than a black object even though they are of the same temperature. The problem comes when most infrared thermometers are calibrated to relate the temperature against the infrared radiation it received of a black object(emissivity=1/0.95). At the same given temperature, a shiny object will emit far less infrared than a black object. The infrared thermometer will then give a much lower false temperature reading. It is okay to use infrared thermometers if accuracy is not much of a issue or if the thermometer is specifically calibrated for that purpose. In our case, even a 10-20C error can make a difference whether the LEDs are operating at the correct temperature or burning itself out. So black heat sink is always better? Not always the case. Black color is either a anodized coating or simply black paint. This coating no matter how thin, its a insulator of heat. So when to use black or bare heat sinks? As a general rule, use black if there is no active cooling(no fans). The black heat sink would be able to lose heat faster via radiation despite acting as a thermal insulator itself. Use bare, if there is active cooling. Without the thermal insulator(black coating), the heat sink would be able to lose heat faster via conduction and convection. In a nutshell, Using aluminium plate might not necessarily be a bad choice but you have to build it thicker, bigger or introduce more active cooling

Correct, provided the temperature measurement is accurate. If the temperature reading is skewed by 20C then the LEDs will start to dim in about 6months or not.

Initially I thought infrared thermometers are accurate until you use with reflective surfaces. I'm involved in temperature control of special steel for heat treatment purpose. I tried measuring the shiny surface but kept getting very low temperature but the contact thermocouple shows that the temperature is just right. Then I tried measuring the mill scale(black color) on the steel and finally the temperature tallies with the contact thermocouple. The initial temperature of the infrared thermometer is ~140C and the contact thermocouple showed 200C, that is a difference of 60C! You can do a simple search on the internet regarding the limitation of infrared thermometers. Typically infrared thermometers are calibrated at 0.95 emissivity, with a black body emissivity at 1.0. The more reflective the surface, the higher the error. FYI, I'm also using the Fluke 62 because its the cheapest fluke I can find ... around $100+

LEDs maximum temperature is rated at the LED junction which cannot be measured directly. Its not as simple as just taking the measurement of the star. First of all, we need to consider the thermal resistance of the LED. For SSC P4, its 8.8C/watt. Assuming that there is a thermal resistance of 1.2C/watt between the LED slug and aluminum star. So total thermal resistance will be 10C/watt The formula for calculating junction temperature will be Junction Temp = Thermal Resistance X Wattage + Temperature of star Assuming, temperature of star = 40C, wattage = 4watt, thermal resistance = 10C/watt Junction temperature = 10 X 4 + 40 = 80C. There should be a life span chart telling you the estimated lifespan at a specific junction temperature. I burned hundreds of $$ to realise all these, I certainly hope noone will follow my footsteps.

A contact thermometer would be a better choice in this case. There are several things to ensure good accuracy for infrared thermometers. First of all, the spot size The distance between the thermometer and object determines the measurement spot size. Look at the top of yr thermometer, there should be a simple distance to spot size ratio. Basically, the further the distance, the bigger the spot size. Make sure the spot size(the area of temperature measurement) is smaller than yr object. 2nd, infrared thermometers are designed to work best with black body. Reflective objects will severely skew the temperature measurement. Lens/solder/aluminum anything reflective will show a much lower temperature. 3rd, infrared thermometers cannot measure through glass/plastic/food wraps. You can try pasting a black tape(spot size must be smaller than the tape) over the bare aluminum and try to take the temperature difference between the bare aluminum and black tape. The black tape will show a much higher temperature

You may want to re-consider driving at 1400mA, it would severely reduce the lifespan of the LEDs

I got the 15W version of the E27 screw in LED bulb, not suitable for corals.

SSC should be similar as they use CREE emitters.

If you can get a 1000mA, >30Watt version, that will be great!

Actually possible. My total mounting from LEDs to tank bottom is about 3ft without any lens, still okay for plates and zoos on the bottom

Correct but it will fail safe. If connected in parallel, all will fail dead. You might have to replace all the LEDs which will be expensive.

Its easier to find a 24V, 3A supply than to find a 5V, 15A supply. Running LEDs in parallel uses higher current compared to series. You will need a higher gauge wire to prevent excessive voltage drop and heating. Smart LED drivers are able to run both in series and parallel, other drivers may not be able to regulate the current when 1 of the LEDs fail. That will cause the excess current to flow into the rest of the LEDs thus causing all the rest of the LEDs to fail as well. If you run a fixed 700mA LED driver, connecting 2 LEDs in parallel will cause the current to be splitted, resulting in 350mA in each LED thus underdriving the LED

Dont be surprised that the aiptasias are simply hidding inside the rocks. They usually appear after a week or so if you dont inject directly.

any specific reasons for using Z1 instead of P4 or P7?

very leh cheh 1 leh. Must consolidate order and collect payment. Later got pple want to change this change that, add/cancel order. Anyway, its not very expensive to ship via regular post. However, if you choose to ship premium, you pay more but shipments typically reach you within 2-3days and tracking is available.

I paid around $20+ for some drivers + LEDs. Shipped via DHL

You need to do a solder reflow on the SMC, not easy to hand solder. Where do you order LEDs from? I ordered through ledsupply, they will reach you in less than 1 week.

You need to do a solder reflow on the SMC, not easy to hand solder. Where do you order LEDs from? I ordered through ledsupply, they will reach you in less than 1 week.

I also want leh .. some problems up at cutter electronics .. they wont ship/return emails!

Yap, visited that web before, couldnt find any dealer online for SSC P4 Royalblues.