(...)What makes LED driver unreliable? Low quality components and low life capacitors makes them unreliable. Non-branded Chinese LED driver use regular capacitors which work for only 1000 hours at elevated temperature.
(...)
http://www.charlstonlights.com/blog/difference-between-low-high-quality-led-lights
(...)
When used in combination with LED modules, a driver's service life and failure rate are further decisive criteria.
In real-life applications, care should be taken to ensure components perfectly
match to prevent damaging the system due to the presence of an "inferior" component.
High-quality drivers provide a service life of ≥ 50,000 hours with a failure rate of 0.2% per 1,000 hours.
Low-performance devices come with a service life of 30,000 hours and failure rates of 0.5% per 1,000 hours.
(...)
https://www.vossloh-schwabe.com/uploads/tx_sbdownloader/Leitfaden_Treiber_EN.pdf
(...)
Why use PWM?
•Typically, LED specification sheets provide a particular characteristic, such as color or
efficiency (in lumens per watt), at a particular forward current. These characteristics will
vary based on the forward current. For example, the color temperature may be 3000K at
700mA of current, but only 2700K at 350mA.
A PWM driver will only run the LEDs at the
rated current level or zero, preventing these characteristics from changing as the load is
dimmed. Practically, this means the same color temperature is maintained throughout the
dimming range.
•PWM based drivers can provide a very precise output level, since the LEDs are always on
at the same current level. Changing the operating current linearly, as done with CCR, may
not result in a linear change in light output.
Why use CCR?(Constant Current Reduction )
•
For devices that need to be rated as UL Class 2 for dry or damp locations, there is a lower
output voltage limit for Class 2 devices that use PWM (42.4 volts for PWM frequency > 200
Hz) than those that use CCR (60 volts). Therefore, a Class 2 power supply that uses PWM
will not be able to provide as much voltage as one that uses CCR.
•By definition, PWM power supplies have to run at frequencies high enough to be
imperceptible to the human eye. The higher the frequency, the less likely someone is to
observe flicker. Frequencies below 200Hz may be observable in peripheral vision, and even
higher frequencies are required to eliminate stroboscopic effects in fast motion
environments.
However, higher-frequency power supplies are generally more complex and
expensive to manufacture, especially when low light levels are desired. Other programs,
such as Energy Star, may place minimum requirements on PWM frequency.
•
Because of the fast rising and falling edges of a PWM driver (faster edges allow for higher
frequencies and lower light levels), electromagnetic interference (EMI) can be generated.
This EMI may not be suitable for certain applications.
•PWM drivers, due to their fast edges, may experience performance issues if mounted
remotely from the light source. This is because the electrical characteristics (capacitance
and inductance) of the long wire runs interfere with the fast rise and fall times required for
precise light levels
(...)
http://www.lutron.com/TechnicalDocumentLibrary/048360a_PWM_vs_CCR_LED_App_Note.pdf
(...)
5. Why is it important to use long-life LED drivers? How are they different?
There are two primary factors in the justification of most solid state lighting systems. The first is energy savings. However, there are other alternative lighting technologies that offer high efficiency for lower initial costs. The second justification, lower maintenance costs, is therefore critical. LEDs have the advantage of much longer life than most other lighting technologies. Reduced replacement and/or maintenance costs can be a very significant factor.
However, if the power electronics in the system does not match the life/reliability of the LEDs then the justification of the system is in jeopardy.
The life of an LED driver is mainly determined by the lifetime of the electrolytic capacitors employed. Therefore, to achieve long life of the LED drivers, it is critical to
select long-life, quality electrolytic capacitors.
Also,
since the life of electrolytic capacitors drops by half for every 10°C increase in operating temperature, thermal management of these components is important. Two key factors for reducing the temperature of the capacitors are high efficiency design (dissipating less heat in the driver) and thermal design (effective conduction and/or convection of the heat into the ambient surroundings).
(...)
http://www.astrodynetdi.com/power_supplies/guides/led-drivers/faq/
Conclusion ?
Cheap LED CC drivers and high quality COB leds ,
if implemented together is more of a joke ,rather an efficient LED light fixture.
Leave cheap LED drivers to "match" with cheap ,non-branded ,low -quality LEDS.
High quality ,branded LEDS and/or LED COBs "need" drivers of the same quality class.
Spending certain amounts of money ,energy and time,in order to build a high -quality LED grow light ,
is just vain,if the "weight" is placed more at the LEDS and not at the Drivers.OR vice versa.
Same goes with every other component used,
like heat sinks ,fans, cases ,switches,sockets,EMI filters and so on.
And that is not just my humble personal opinion.
In such matters ,"personal opinions" are almost totally useless.
High-tech characteristics ,including efficiency,long service life ,etc ,claim for hard facts.
And,of course, the sufficient amounts of energy ,time & money spend.
As also obligatory are a very good to exceptional design, top-quality parts used and a high-grade of manufacturing/building practices ,all the way.
Just another 1 ¢ ....
Cheers.