LED Lighting Product Quality

What's should we be looking at LED lighting product for quality?

* Color Temperature and Color Rendering Index (Quality of light)
    Like CFL/Fluorescent light, LED light is not a full spectrum light (vs incandescent light). Early LED light products usually look bluish at around 6500K, for its high lumen efficacy number. Recent years there are more day light white (5500K) and warm white (below 3000K) products which are more suitable to human visible range.
    Color Rendering Index (CRI) is the number in percentage to measure how good the ability of light to bring out true color of objects, Incandescent light bulb is highest as 100. Usually you want the number to be greater than 70 for most applications, professional who works with color would require 90 or higher CRI.
* Heat Handling (Quality for product life time)
   Almost all electronic parts emits some heat, that is especially true for LED products. Lighting grade LED converts about less than 33% of energy into light; the rest would become heat. Driver does better that has only less than 20% of energy become heat. The number is better than traditional light source such as incandescent, fluorescent or HID. However, traditional light sources work at much higher temperature above 400F(200C) or higher; on this end, electronic parts usually won't be able to sustain more than 250F(120C). That's why LED lighting is more sensitive to heat. Heat can damage LED, shorten their life span, decrease light output and ruin their CRI.  Similar effect applies to driver, too.
    Thermo design is big topic in LED lighting since beginning. It's complicated and no fixed rule for user to exam products. One general rule is metal conduct heat better than most of other materials; the other rule is size counts. lots of heat trap in a small space isn't a good thing.
* Energy efficiency
    There are some room of difference in energy conversion rate among various LED products. Since lumen is measured as energy, blue light has higher lumen number than other light. LED working temperature also plays a role, too. Cooler LED does better work to convert electricity into light. Of course, circuit efficiency made few difference, too.

    All these variance doesn't compare to difference made by basic lamp design. LED by nature is directional light source, while all other light source is omnidirectional. Use LED to make a omnidirectional lamp requires mounting LED at different directions.  On the other hand, use other light sources to make a directional lamp, such as ceiling light/Wall light/ shop light, usually include reflective panel to reflect light to desired direction. But no matter how it does, there is no match to directional lamp that uses LED. in some cases, directional LED lamps use only half of energy as fluorescent ones.

Easy LED Lighting quality

Our LED module uses aluminum plate as mounting bracket, which also makes direct contact with the belly of all LEDs.  The aluminum takes heat away from LED and allow them to work at much cooler temperature.
Our LED kit or lamp uses external driver that has much durable design. It's water and dust proof and doesn't have to be crumble together LED heat source.

How to trouble shoot a LED kit? (and Quick fix)

Every kit we shipped had gone though a 10 hours burn in test, however the kit may still got damaged during shipping or by installer.  And these LED chips can be damaged by ESD (Electrical Static Discharge) before they are installed and grounded. ESD can be introduced as easy as one finger touch and a lot depends on what the installer wear (like sweater and shoes). The movement of human body and cloth can generate static charge and it may build up, and we would like to release that charge before we touch LED module. One common practice is to release charge from installer prior to touch sensitive electronic parts. Such as touch grounded environment object with bare hand or body part.

But damage may have been already done, So we need your help to determine where had gone wrong.
First, you should describe what model is your kit and what's the problem. Tell us how many LED modules are linked together. Then we need you to identify the model number of your LED driver, like shown in below picture, the model number is LPC-60-1400.

Then with the wires correct connected and tucked away, we want to do a live test with power turn on.
Our test should avoid any AC part and only perform on our LED module. If you have a voltage meter like multimeter, use it to measure driver output, read the voltage (LPC-60-1400 should output 42V)
But most of us don't have a meter, we can test it one by one by using a metal tool to short the two solder points of the LED module. Be aware, when you short circuit one module, the rest of modules may come up in full brightness, so be prepared for that. When a bad module is short circuits, all good modules will come up in full brightness. A quick fix is to connect the two wires of the bad board and rest of modules will continue to work. That's if you know how to do wire splicing. 

Fig: use a metal tool to short circuit a module

These points only has DC power supply to, it's safe to touch with hand..

LED kit burn-in process

Have you seen new installed LED street light just went dark after a few day? Have you seen LED traffic light got broken just after a short period of time? Isn't LED lighting suppose to long life? Why do we see so many failure LED around us?
After our study, we find out this is a popular problem among high power LED; less with lower power LED. One of common reason is bonding wire broken.

What's bonding wire? It's a thin wire that connects silicon die and Chip package connector. With high power LED, its chip die can go up and down in a wide temperature range; and due to material can contract and expend at different temperatures, this bonding wire may broke if the die, bonding proxy and connection pad are in an odd arranged position.
Does LED manufacture test their product? Yes, they do, to an extend. their expensive tester machine can make contact to chip connectors without making a solder point. However, they won't occupy expensive tester machine with low price (few dollars) chip for a prolonged time.
So this has to come down to us.

Modules from Easy LED Lighting are basically tested by China manufacture, so they do work. But after we were into this business a while, we found out there are a low percentage of modules would fail after just a few days of usage; otherwise, they would work for a long long time.

Right now, we burn in test our kits products, every kit will gone through a 10 hours burn-in process with on/off sessions control by timer, just to ensure their quality.