Going the Do It Yourself route will save you close to half the cost of a quality commercial fixture. However everyones experience level is different and stuff happens. We are starting with the most common errors and ways to test for them. Almost all the problems with a couple of LEDs not lighting is due to Poor soldering. Personally my soldering has improved greatly since my first fixture. If you are the least bit unsure of your soldering skills, we highly recommend using the BJB Solderless Connectors or our pre wired strips.
Here We are using the Sperry DM-4100 Multi-Meter. It is set to the diode mode and the positive lead is placed on the + side of the LED and the negative on the – side of the LED. We took this one step further and tested the solder connections by starting at the previous LEDs – and the next LEDs +. This test will tell you if you have a good LED. (Click Photo for Full Image)
This shows way too much solder. All it takes is a little to spill over the edge to cause the LED not to light. The next two photos are how to test for this using a Multi-Meter.(Click Photo for Full Image)
In the above photo the current is traveling through the Heatsink then up the spilled solder to light the LEDs. The below photo shows a simple continuity test. Both show a bad solder.(Click Photo for Full Image)
The solution is rather simple. Clean up the solder and re do it. Its not a bad idea to do these tests as you assemble your fixture. It only takes a second and will save you time in the future. This particular fixture worked fine with 48Vdc drivers but when it was upgraded to a single 150 Watt Inventronice the soldering errors became quite apparent at the higher voltage.
Here you can see the wire touching the star and grounding out the connection, the stars are made of metal!
Cold Solder, wire not pretinned
Here you can see that the wire was not heated up and tinned. The wire was not heated up so the solder only cooled on the outside of the strands rather than flowing thru it.
Cold solder pad
Here you can see that the Pad on the star was not heated up to receive the solder. You need to heat up the pad to attract the solder, its best to pre tin the stars with solder so when you attach the wires its easier.
Proper Solder Points
Here you can see the stripped part of the wire is in the solder over the pads of the star. The sheathing is protecting the rest of the wire from contacting the star.
Why is my driver Blinking?
When you go too low with your forward voltage the driver begins to blink to alert you that its going below its minimum operating range.
The voltage requirement of the LEDs goes down as you supply less current to it (dimming it)
the 60-48d driver has a minimum of 24v to run.
Cree XP-* LEDs can run between 2.8-3.7v
Lets say 3.7 is at 1000mA
as you dim the driver down the voltage goes down.
|How many LEDs||mA applied to string||Foward Voltage per LED||Total Voltage|
|Cree XP-*s||8 LEDs||100mA||2.8v||22.4v|
|Cree XP-*s||8 LEDs||350mA||3.1v||24.8v|
|Cree XP-*s||9 LEDs||100mA||2.8v||25.2v|
The 60-48d driver can only dim down to 10%
Below 10% the driver simply shuts off.
Cree XR-E optic ripped off
Burnt out LED