Issue with a 10 Watt Power LED Driver Supply

[Yoda Man]

Greetings All;

I ordered from E-Bay 10- 10 Watt SMD LED's, I then ordered a couple of 10 Watt drivers for these lights.

The spec's are as follows:

10W Driver
Driving power: 10w
model: 3 series 3 in parallel
Input Voltage: 85V~265V
Output Voltage: 9-12V
Current:900mA
Efficiency > 88%
Power Factor >0.98
Operating Temperature: -20~80

I received the drivers early and am waiting for the LED's to arrive so I decided to try and test the drivers this morning.

I wired them up to my 220 Volt AC current the measured with a multi-meter the DC output. I was expecting 12 volts DC or so but

I was showing a pulse of between 17 to 19 volts DC.

Thinking that a load might be required I used a breadboard with a high ohm resister and 8- 5mm Blue LED's in series.

The LED's all worked but there was pulsing as if the current was fluctuating, one thing I did noticed was that the circuit board used only to Diodes

and not the four I expected for rectification.

As a novice I have come here hoping that someone might know what is happening or if I have two defective modules?

Thank you in advance.
 

[audioguru]

A blue LED is about 3.2V but some high power LEDs have a few of the LED chips in series. If your blue LEDs survive the high current of 900mA then the eight you connected in series need about 25.6V which is much higher than the rated output voltage of the driver. Why eight LEDs?

Try using a load of 10.5V/900mA= 11.67 ohms or a 12 ohms/20W resistor.  

[Yoda Man]

Thank you for the reply.

Regarding the Blue LED's that I installed it was simply a test to try and find out why the LED driver was showing the 17 - 19 volts DC instead of the 9-12 Volts

advertised. This driver or rather drivers will be used to power 1- 10 Watt 12 Volt SMD chip and the consern is that to voltage will be to great for the SMD.

I wanted advise here before contacting the seller on E-Bay!

[audioguru]

An LED is driven from a current, not a voltage. We do not know if the high power SMD LED has a built-in current-limiting resistor. The LED sets its own voltage so the 17V - 19V will probably drop to 12V when the 12V/900mA LED is connected.

10W is a lot of heat for an LED. Do you have a suitable heatsink for it?