Choosing an LED Light on Price

LED lights look much the same but there is a difference and if you are thinking of changing to LED lighting it is worth thinking about this.   You will hear tales of clever people buying their LED lights from EBay or AliBaba for $10 each and will wonder why they cost so much from local suppliers.
Here are some of the reasons.
The LED chip can vary in price by as much as 250%.  The number of buyers of LED chips is limited so anyone selling rubbish at high prices would soon run out of customers.  So it is a reasonable assumption that the higher the price the better the quality.  It is worth bearing in mind that the lower end products are produced for the local market in China and are not expected to be exported.

Perhaps the most critical part of the LED light is the driver.  The driver has the job of converting the 230 Volt Alternating Current into Direct Current flowing at a constant number of Amps through the chip.
The Alternating Current reverses direction 50 times a second so the first job for the driver is to reverse one cycle so that there are two pulses of electricity flowing in the one direction.  The difficult job is to smooth these pulses into an even current flow and this is where there is an enormous difference in the quality of the drivers.
The best will have about a 3% ripple in the power of each cycle while the cheap models can have a ripple of up to 45%. (The per centage is of the value of the average current)

The ripple will cause the light to flicker but because it does so at 100 cycles per second it is not visible to the naked eye.  However the effect can be felt and people can suffer headaches, eye strain, or migraines.  This actually was the problem with the old style fluorescent lights.
If the driver is supplying say 700 milliAmps to the LED, the ripple as it passes will supply a higher and lower current with the average being 700 mA.  The higher current produces more heat which is not completely dissipated during the lower current supply.  The heat accumulates and stabilises at a higher temperature, how much higher depends on the per-centage of the ripple.    This will shorten the life of the LED – dramatically with the larger ripples.
Probably 90% of the failures of LED lights are caused by the driver.

The other areas where cost savings are made  is by scrimping on the heat sink, wiring and connectors
So in practice how can you tell if the $10 LED light is great value or junk?  Often by looking at the finish and wiring it is obvious, but not always.  A foolproof way is to use your phone camera to look at the light operating.  Any flicker will show up even though it is not visible to the naked eye.. 
Do not buy a strongly flickering light. If the lowest price is the only criteria, best stay with energy saving lighting.