Reviewing 20W COB LED 2828 Package
LED lamp brightness should be tested with specific instruments that measure light intensity in lumens and power consumption with a watt meter. Dividing these two yields a value known as lumens per watt (Lm/W), which is used to compare LEDs. It implies that the better the LED, the less power it consumes and the more light it generates. Unfortunately, I lack this equipment, and I only evaluate the electrical properties of LEDs and their drivers. Although it is not a comprehensive evaluation, it may be valuable for certain individuals because I have not seen these reviews elsewhere. On the other hand, many low-cost LEDs on the market lack a true nominal power rating.
I received a 20W COB LED to test at 300 mA. I performed this test with the Jiaton 8-24W 300mA driver. The LED has been turned on for two minutes on the proper heatsink, and the temperature has almost reached equilibrium.
The COB LED measures 28 mm x 28 mm and contains 40 LEDs (2B20C), divided into 2 rows of 20. Each LED is rated at 0.5 watts. This LED’s specifications are as follows:
Dimensions: 28x28mm
Diameter of the central circle: 24.5mm
Chip: Sanan, 13X32MIL; Lumens: 2100-2300 at 320mA; Current: 320mA; Voltage: 60-66V.
Broadcast angle: 140 degrees
It is claimed that this LED is a flip-chip LED, a method of making LEDs and chipsets. One advantage of this construction method is that heat is more effectively transferred to the heat sink.
8-24W driver used: BP2866 driver IC and this driver is non-isolated.
The test results are as follows:
The AC watt meter started at 19 W. After 2 minutes, as the temperature stabilized, it dropped to 17.7–17.6 W. On the DC side, the current started at 300 mA and decreased to 282 mA. The voltage ranged from 58 to 60. However, the power factor—like most non-isolated drives—was only 0.6. While non-isolated switching devices with power factors of 0.9 or higher exist, they are uncommon and more expensive. Also, there are no IEEE standards for these drivers.
Furthermore, as a different heatsink was used for each test, temperature measurements were omitted.