FAQ: 1.1 Questions on fixtures manufacturing.
- 1.1.1 What should be minimal height from the assembly to the water surface be?
At minimal height (usually required when the fixture is installed in the aquarium lid) light diffusers should be used without the installation of secondary optics. In this case you can install assemblies at a distance of 50-70mm from the water surface for sea water aquariums and 70-100mm for fresh water aquariums. If a lower installation is required, the light diffuser ring height must be reduced. In any case, never forget the fact that all electronics and light-emitting diode assemblies should be well protected from moisture! This is very important when the assembly is installed in the aquarium lid.
- 1.1.2 Is passive cooling possible when the fixture is installed in the aquarium lid?
Yes. Thus it is necessary to make a window in the assembly fixture casing of no less than ¾ of the heatsink's surface area.
- 1.1.3 How should the fixture assembly heater be actively cooled when installed in the aquarium lid?
If it is necessary to provide cooled air charge into the fixture assembly to remove the heated air, it is better if the cooled air is charged through the holes in the lid, located at a distance from the ventilators (fan), and the hot air is discharged with the ventilators out from the aquarium lid. To make sure the cooling is performed successfully, switch on all light-emitting diode assemblies at full power. At two hours, if the heatsink temperature is not more than 70OС when measured with a pyrometer, the system is operating nominally. Please, use a pyrometer to measure the heater temperature, as the metal temperature of about 70OС, when touching, seems to be burning hot, and to differentiate 70OС from 80OС is impossible.
- 1.1.4 I cannot make connectors for installation of 12x LED assemblies manually. Can I use soldering to connect the fixture components?
Yes, in theory you can use soldering, but initially it will require removing the connectors from the components MCPCB. But our experience has shown that this procedure is not always executed without problems. Quality soldering requires specific skills. That is why we recommend purchasing a crimping tool. If it is not possible for any reason, you can use such handy tools as forceps, manicure tongs, etc. to crimp the contacts.
- 1.1.5 Express delivery of a crimping tool from China is rather expensive because of its rather large weight. I would like to buy it myself in the nearest shop. What kind of tool do I need?
You will need a D-SUB type crimping tool with wrench Jaws around 4mm, designed to work with AWG22-AWG26 wire sizes.
- 1.1.6 Why do you advice using only expensive power supplies? There are many power supplies with the same voltage and power rating that are priced much cheaper.
Components of a light-emitting diode assembly of our manufacturing are calculated for a service life of greater than 10 years. Inexpensive power supplies are not designed for such a long operating period. Additionally, the current efficiency of cheap power supplies is much lower than our recommendations. Therefore, the price differential will be paid back several times due to the higher efficiency.
However, problems will not arise when using cheap power supplies with our components. They will work stably and qualitatively, even with the cheapest power supplies.
- 1.1.7 Why do you recommend using large heatsinks for passive cooling?
When using passive cooling, namely, without ventilator usage, the heatsink should be large, as the air's free convection is insufficient for effective cooling, for this reason we must use large heatsinks for the crystal temperature of the LED's to remain within specification.
- 1.1.8 How reliable is your heatsink on thermal tubes?
Damage of a thermal tube rarely occurs. Our heatsinks on the thermal tubes are overdesigned, therefore even the damage of two of the four thermal tubes will not result in problems with cooling. In this instance the crystal temperature will rise only 7-100С – well within specification.
- What are the heatsink requirements?
The heatsink should have a bottom base thickness of not less than 4mm for 12x LED assemblies and not less than 2mm for 3x assemblies. The heatsink fins should not be higher than 40mm. Thus, the gap between the heatsink fins for passive cooling, i.e., without ventilator cooling, should be rather large – for fins less than 20mm, the gap must be greater than 15% fin height, and for fins 20-40mm, the gap must be greater than 20%. If you plan to install a ventilator, the fin's gaps may be more closely spaced, but a smaller gap will require a stronger fan (higher CFM).
Attention – all our components are calculated to be used together with passive cooling. But if you wish to reduce the fixture weight, you can use heatsinks with ventilator cooling.
- 1.1.10 The pin-type heatsink is more effective than the fin-type for passive and active options for cooling, isn’t it?
Yes, the pin-type heatsink is much more effective than the fin-type, especially when it is used in passive cooling. You can divide the result of our calculation program by 1.5 when using this type of heatsink in passive applications only. We do not recommend reducing the heatsink's calculated area for active cooling.
- 1.1.11 Should the heatsink cooling ventilator blow TOWARDS the heatsink or AWAY FROM it?
If you have an open installation of the heatsink, and the ventilator is not a low profile device (>20mm) then it does not matter. If ventilators are low profile devices and are installed in a closed casing, they should blow AWAY FROM the heatsink.
- 1.1.12 Is the radial ventilator, AKA “turbine”, more effective that the typical ventilator?
A good radial ventilator produces a larger CFM than typical ventilators, so it is worthwhile to use it for fin-type heatsinks. When using this type of ventilator, it is necessary to close off the heatsink at its top so that its fins form a square cross section of tubes, and the ventilator would blow at their butt end. Please take into account, that with this cooling configuration, all these improvised tubes should get their own portion of air from the ventilator. Also the length of such a tube space should not be so long that the air stream, blown out from opposite end of the tubes, would have a temperature greater than 500С. To achieve this you can place ventilators in the middle of the fixture, so that they blow air from the center to the butt ends. For very wide fixtures, the ventilator can blow from one front side to the other. By organizing your cooling in this fashion, you can use a heatsink with half the surface area given by our calculation of the heatsink surface for active cooling.
- 1.1.13 Can I use a computer processor cooling system for cooling the 12x LED assemblies?
Yes, the output of the weakest cooler for a processor will be sufficient for cooling the 12x LED assemblies. However, there are two considerations. First of all, the assemblies should make contact with the heatsink on an area of not less than 40mm diameter from its center. Second, keep in mind that processor coolers usually use heatsinks with very tight ribbing, thus, in the event of ventilator failure, there is a high probability of overheating and destruction of the light-emitting diode assembly, even if it was operating on low current.