I have a half dozen 50w LED floodlights. Build quality isn't amazing although purchased from big DIY chains. They are very typical units that look like this:

I've had the LED drivers inside them fail in just about all of the units but in one particular location I've replaced the driver 3 or 4 times. This has included replacing the LED itself as a precaution. I should mention that each time I've replaced drivers I've used a different brand.

The symptoms are always the same, a slow flashing/strobing of the light that occurs instantly when you turn it on and is never rectifiable until the driver is replaced. Sometimes once I've replaced a driver the light will work half a year before it fails again. At worst, the latest new driver I installed in the lamp lasted only a week or two.

I wondered if this was a heat issue but the casing never feels that hot. I also during the refurbishment added a large quantity of thermal paste behind the LED.

The location in question is at the end of an outhouse building we have connected to an ok quality looking internal wall power cable that runs along the exterior wall of the building. I'm just wondering if this is bad luck that the same location has failed so many times or if there could be something else at play here with a bad quality power source.

Should I try earthing the lights? Add some kind of filter to the power source ?


My last failed driver was this model:

Any ideas would be greatly appreciated.

 

Light craps out at the outhouse . They solved the don’t have to replace the lightbulb issue. Make the power supply die out!

Would be nice to know what failed in the driver. Could be something is getting hot. Could be surges. Could be... poorly rated components. Need more info.

I would focus on the power supply since that’s what’s failing not the LED

 

Hello,

What are the specifications of the used leds?
It sound like the driver is not powerfull enough to drive the led and goes in some kind of protection.

Bertus

 

Hello,

What are the specifications of the used leds?
It sound like the driver is not powerfull enough to drive the led and goes in some kind of protection.

Bertus

This happens very randomly in terms of when it initially starts occuring, its not after say x minutes. It's a permanent change that occurs weeks/months after usage starts.

 

Light craps out at the outhouse . They solved the don’t have to replace the lightbulb issue. Make the power supply die out!

Would be nice to know what failed in the driver. Could be something is getting hot. Could be surges. Could be... poorly rated components. Need more info.

I would focus on the power supply since that’s what’s failing not the LED

I'm not enough of a guru to really diagnose what is wrong inside the drivers. I do still have all the old ones so I guess I could open up one but I would need to be hand held through that process so not ideal for this post I guess.

 

Hello,

What are the specifications of the used leds?
It sound like the driver is not powerful enough to drive the led and goes in some kind of protection.

Bertus

The drivers were always capable of a range of DC ratings and my LED was always within that range... normally the LEDs are specified as "30-34V". The image in my original post of a driver is the actual driver I last used that only worked for a week or two before failure, so you can see from that the spec.

 

That is a CE certified device rated for 265VAC/60HZ. What is your mains voltage and frequence?

EDIT: Actually it says 85 - 265VAC

 

Can you take one of the bad ones apart and take a picture? When the components release their magic smoke it leaves trails behind. Also notice for smells of burnt plastic...

 

That is a CE certified device rated for 265VAC/60HZ. What is your mains voltage and frequence?

EDIT: Actually it says 85 - 265VAC

It's not rated for 50/60 ? That's what I interpreted it to state. my frequency is 50hz.

 

It is... that's fine 50 or 60 shouldn't matter for this.

 

It's not rated for 50/60 ?

Can't tell from the markings and I would expect it to be marked 50/60. Shouldn't matter for that device. For outdoor use it should be waterproof? That doesn't look it unless it's encapsulated under the cover or in a watertight case? I am suspicious about chinese devices (which I assume it is from the HannaHong) being actually CE certified or just marked that they are...

 

Can you bring a unit inside and run it for a few hours while you have a thermometer on both the LED and the driver? That will be a pain, because the light will be pretty bright, but it beats trying to measure one mounted outside.
Also, can you double check the power source to see if it is out of spec?
The similar drivers I have are potted so it would take an expert to trace any magic smoke.

 

I think I know what you mean. I have a similar supply and it has silicone at all connections. It may be potted too for water protection. Maybe 50 watts mean something else in Chinese.

 

This is typical of a whole range of cheap Chinese electrical goods . They are not designed to last ...Some say they are DESIGNED to fail ... No doubt the heat sink is not adequate , which will result in early led failure , and clearly the driver is not designed well....

I would suggest you not feed 50W into the led , perhaps 20 or 30W ... youre eye will not perceive the light output as massively decreased , but use a 50W driver with a resistor in between it and the led ...

Under powering both components must result in a longer life.

 

I have a similar problem at a restaurant where I am a partner. The 48 inch "LED tubes" around the outside are suffering failing LEDs. Each tube has three series strings of 32 LEDs in series. First the sections start blinking and then after a while they fail to illuminate at all. The line voltage measures 123.8 to 124.3 at the control switch. That is a bit high, I know. The strange part is that inside are fixtures using the same LED tubes and they have no problems at all. I have checked and found that in each failed 32 LED section there are 1 or 2 LEDs that do not light at the same voltage as the others, or they do not light at all. My guess is excessive current but I have not been able to verify that.

 

This is typical of a whole range of cheap Chinese electrical goods . They are not designed to last ...Some say they are DESIGNED to fail ... No doubt the heat sink is not adequate , which will result in early led failure , and clearly the driver is not designed well....

I would suggest you not feed 50W into the led , perhaps 20 or 30W ... youre eye will not perceive the light output as massively decreased , but use a 50W driver with a resistor in between it and the led ...

Under powering both components must result in a longer life.

What kind of resistor would I want if I did this? What types to look for or avoid ? I'm happy soldering this in but not normally buying components like this so any guidance would be great.

 

I wondered if this was a heat issue but the casing never feels that hot. I also during the refurbishment added a large quantity of thermal paste behind the LED.

I do not have a solution to the whole problem, but the above mentioned "large quantity of thermal paste" may be a problem.

Thermal paste actually insulates very well, but transmits heat many times better than air.

 

What kind of resistor would I want if I did this? What types to look for or avoid ? I'm happy soldering this in but not normally buying components like this so any guidance would be great.

The size of the resistor depends on the current and how much voltage needs to be dropped. The kind of resistor that I would suggest is wire-wound, but the wattage rating and resistance value need to be determined. So the first step is to measure the voltage across the LED assembly.
Since the LED supply is a switch mode device, the lower the supply voltage the longer the switching regulator "ON" time has to be to deliver enough power, and that may be increasing the stress on parts with no safety margin left.
So another choice could be to use a power supply with a lower output voltage but that is designed to last a long time.. But you will still need a current limiting resistor unless you get a supply that has adjustable current regulation.

What I see on the photo of a failed supply is a current rating of 1500 Ma, or 1.5 amps. At 50 watts and 30 volts the current would be over 1.5 amps, and that may be a big part of the problem. So my first suggestion is to try powering the light from a 12 volt battery and see how much light you get. Then try 2 of the 12 volt batteries in series, for 24 volts. If that is enough light then you can buy a 24 volt 2or more amps power supply and be all set. And if you can get one that is adjustable then possibly raise the voltage up a bit.

 

Hello,

Why do you not try a led driver with a lower current?
Meanwell has drivers for 1050 and 1400 mA:
https://www.ledsupply.com/led-drivers/mean-well-lpc-led-drivers
The LPC60 series would probably do well.

There is also the LPF60 series.
Those have currents of 1.12 , 1.25 and 1.43 A available:
https://www.ledsupply.com/power-sup...ries-constant-voltage-constant-current-output

Bertus

 

If the LED light draws more current at the supply voltage, and if the supply voltage is not adjustable, then that would not work. Given that these supplies have no apparent adjustment capability, the lower power would need to be provided by a lower voltage. So to avoid overloading the supply a greater current rating at the same voltage would be required. That is why I suggested using a lower voltage supply. Running anything at it's rated maximum is seldom a good idea, especially with poor quality imports.