DIY LED driver for reef lighting
- Thread starter der_wille_zur_macht
- Start date
Not bright eh? Have you verified how much current they're being driven at? Maybe it's less than you assume?
The diodes were sold to me as XPE2. The spec says they should have a forward voltage of 3.15 @ 1000 mA. I have 7 in a string and the drop is 15.3v. The actual part they told me it was is XPEBWT-L1-0000-00BE7.
They came on a star pcb but the print doesn't look legit... What do you think?
I bought the CAT4101 back when I had a reef but moved across provinces and left all the hardware sitting in a box for 3 years. I recently decided to try it out just for fun. That's why the lights are white, I don't really have a use for the other colors right now.
They came on a star pcb but the print doesn't look legit... What do you think?
I bought the CAT4101 back when I had a reef but moved across provinces and left all the hardware sitting in a box for 3 years. I recently decided to try it out just for fun. That's why the lights are white, I don't really have a use for the other colors right now.
As O2Srplus said, test the current. If they are being driven on a low current, you'd see a lower voltage across them and less light.
Cree only supply the actual emitter - the star is usually supplied by whoever reflows the emitter on to it, so the lettering could be done by anyone and still a genuine cree LED.
Tim
Cree only supply the actual emitter - the star is usually supplied by whoever reflows the emitter on to it, so the lettering could be done by anyone and still a genuine cree LED.
Tim
Hi Tim,
How do I test the current?
I've set the power supply to 24v using the trim pot on it. The PWM on the CAT4101 is connected to 5v. If I recall correctly, the CAT4101 board as designed here, is 700mA so the voltage drop on the xpe2 should be 3.05.
Now 15.3 / 7 = 2.19 so I'm pretty far from what I should see right?
How do I test the current?
I've set the power supply to 24v using the trim pot on it. The PWM on the CAT4101 is connected to 5v. If I recall correctly, the CAT4101 board as designed here, is 700mA so the voltage drop on the xpe2 should be 3.05.
Now 15.3 / 7 = 2.19 so I'm pretty far from what I should see right?
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Using a multimeter on the ammeter setting. It needs to be part of the circuit (ie the +ve supply goes the the ammeter and then the ammeter connects to the +ve in on your LEDs).
Or, just drop a 9V battery across three of them and see if they look brighter then when normslly powered up. A 3V source across one is easier, if you have one...
2.19 is about riht for XPE at 700mA. For XPE2, it would be more like 10mA!!!!
Tim
Another simple method to use if your meter can't handle amps (some only measure mA) you would need a meter with a 10amp setting(usually a separate plug for the positive lead.
you can use a resistor wired in series with the string. a 1ohm resistor works fine for this you will want at least a 1 or two watt resistor so it doesn't burn up during the test. you then set the meter to measure milivolts or volts and measure across the two ends of the resistor. using a 1ohm resistor the voltage reading equals the current. I.E. 700mA current would give a voltage of either 0.7volts or 700mV depending on the setting on your meter.
