stephenrwright
New member
A 10x - 30x Zoom Stereo Microscope is nice too, I got an old used one on eBay for $65, helpfull when trying to line up the smd parts. my old eyes dont see the small stuff very well anymore.
DIY LED driver for reef lighting
- Thread starter der_wille_zur_macht
- Start date
A 10x - 30x Zoom Stereo Microscope is nice too, I got an old used one on eBay for $65, helpfull when trying to line up the smd parts. my old eyes dont see the small stuff very well anymore.
der_wille_zur_macht
Team RC
I've used those Rebels many times and they definitely drop less than a typical Cree XR-E or XP-E, but the number you're seeing still seems a touch low.
Are you able to adjust the input voltage while you watch the output current? If so, make sure you're providing enough input voltage - start with it low, and adjust it upwards until the current stops increasing. Then you'll know the regulator is actually in it's proper operating range. The datasheet specs a .5v minimum drop, but iirc SpacedCowboy found it took a little more than that.
Are you able to adjust the input voltage while you watch the output current? If so, make sure you're providing enough input voltage - start with it low, and adjust it upwards until the current stops increasing. Then you'll know the regulator is actually in it's proper operating range. The datasheet specs a .5v minimum drop, but iirc SpacedCowboy found it took a little more than that.
TheFishMan65
New member
It pays to procrastinate - a little. Gold Phoenix has dropped the price to $89 for 1000 square inches - ten boards in my case. So my driver price just dropped 0.125. I plan to order a little later today, just a few final touch ups. I checked all my caps 
They were good but I did find a few small enhancements.
I am not sure since I am ordering for more than one board, but prices will be about $32.73 for one board, $4.09 per driver, or $0.68 per LED. This does not include a power supply, since I have not picked one yet. I am hoping mpja will restock the 8.3amp ate 24v. If I add $20 for a power supply I am up to $1.10 per LED.
They were good but I did find a few small enhancements.I am not sure since I am ordering for more than one board, but prices will be about $32.73 for one board, $4.09 per driver, or $0.68 per LED. This does not include a power supply, since I have not picked one yet. I am hoping mpja will restock the 8.3amp ate 24v. If I add $20 for a power supply I am up to $1.10 per LED.
der_wille_zur_macht
Team RC
Is that a typo? Their "normal" deal price is $89 for 100 square inches:
http://www.goldphoenixpcb.biz/special_price.php
TheFishMan65
New member
Yes that was a typo.
der_wille_zur_macht
Team RC
I'm disappointed. Somehow I was hoping you'd gotten them to give you an unbelievable price. 
TheFishMan65
New member
Still they did drop 10%. So I am happy
SpacedCowboy
New member
Actually that was a mistake on my part - I corrected myself in a later post
Once I was using the correct Vf for the LEDs in the calculation, I couldn't actually see *any* voltage drop from the chip. I was joking that we seemed to have found a perfect driver chip [grin], but presumably it was just beyond the resolution of my el-cheapo multimeter.
(I really need a new multimeter! I was trying to measure the resistance of some nichrome wire a couple of weekends ago. I wanted 5 ohms-worth (about 6 inches) of wire. Not 6 ohms, not 4 ohms. 5 ohms was needed. The meter was telling me it was somewhere-between-2-and-10. [Sigh])
Simon
shackscs
Super Premier Member
While waiting for my driver boards to arrive I need to hook up my array to my Meanwell 35-700 LPC driver. Connected the brown and blue wires to the white and black wires on the cord going to the wall outlet.
I then connected the red and black wires to a test LED and "Poof" fried it like an egg. It was an older LED but I am glad a tested before going live with my array. The driver will be used to run 12 3w Cree XPE LEDS.
I also tried to test a string of Solaris LEDS (5) and get the same result a Pop and then death to the string.
I did purchase a multimeter and am getting .69??? on the display. I need help with the multimeter but I am wondering what is going on with the driver.
I then connected the red and black wires to a test LED and "Poof" fried it like an egg. It was an older LED but I am glad a tested before going live with my array. The driver will be used to run 12 3w Cree XPE LEDS.
I also tried to test a string of Solaris LEDS (5) and get the same result a Pop and then death to the string.
I did purchase a multimeter and am getting .69??? on the display. I need help with the multimeter but I am wondering what is going on with the driver.
kcress
New member
TheFishMan65
New member
shachscs,
I have not uses the Meanwell, but some are set at the factory for 1.3 amps and need to be turned down before use. Also DO NOT connect the LEDs after power is applied to the meanwells.
What is your multimeter set to and how is it connected. You might try getting about 15-20 homs of power resistors. Use those instead of an LED string. You can measure the voltage and current and make sure things are set without risking damage to the LEDs.
Radioshack $1.99: 10 ohm power resistor 2 pack
I have not uses the Meanwell, but some are set at the factory for 1.3 amps and need to be turned down before use. Also DO NOT connect the LEDs after power is applied to the meanwells.
What is your multimeter set to and how is it connected. You might try getting about 15-20 homs of power resistors. Use those instead of an LED string. You can measure the voltage and current and make sure things are set without risking damage to the LEDs.
Radioshack $1.99: 10 ohm power resistor 2 pack
TheFishMan65
New member
As I said I have not worked with the meanwell and was only repeating what I think I read.
However, resistors are not a bad idea for people to start with. They are inexpensive and behave similiarly to LEDs. Measure the resistance before you start and wire them in the circuit instead of LEDs. Measure the voltage and calculate the current. Current = Voltage / Resistance (I = V/R). 20 ohms is like 6 LEDs with a drop of 3.33 volts, right about where we are running.
Since our designs are current controlled when the LEDs are switched for the resistors the current should stay the same. If you are trying to adjust your power supply for maximum effieiciency the you may need to make a small change to the voltage when the resistors are replace with LEDs.
However, resistors are not a bad idea for people to start with. They are inexpensive and behave similiarly to LEDs. Measure the resistance before you start and wire them in the circuit instead of LEDs. Measure the voltage and calculate the current. Current = Voltage / Resistance (I = V/R). 20 ohms is like 6 LEDs with a drop of 3.33 volts, right about where we are running.
Since our designs are current controlled when the LEDs are switched for the resistors the current should stay the same. If you are trying to adjust your power supply for maximum effieiciency the you may need to make a small change to the voltage when the resistors are replace with LEDs.
marspeed
Member
perikaruppan
Member
Friends,
i am not going the CAT way, but the ZXLD way as i had hurriedly purchased it.
All PCB work is done. Power supply is ready, 6 LEDS wired up
thinking of supplying 24V to the Drivers..
i have 3 drivers in 1 board with 24V/3A power supply...
to test, can i startup the Driver without LOADING the output with LEDs? so that even if the circuit gets blown, my LEDs will be alright? Thinking of just checking the output of the Driver to see what the output voltage is as it is a step down one
then once the PCB doesnt blow, then thinking of connecting the LEDs to the Output. Is this alright?
i am not going the CAT way, but the ZXLD way as i had hurriedly purchased it.
All PCB work is done. Power supply is ready, 6 LEDS wired up
thinking of supplying 24V to the Drivers..
i have 3 drivers in 1 board with 24V/3A power supply...
to test, can i startup the Driver without LOADING the output with LEDs? so that even if the circuit gets blown, my LEDs will be alright? Thinking of just checking the output of the Driver to see what the output voltage is as it is a step down one
then once the PCB doesnt blow, then thinking of connecting the LEDs to the Output. Is this alright?
der_wille_zur_macht
Team RC
Peri,
You CANNOT test the output without a load attached - the IC will basically just pass through the input voltage if there's no load to tell it otherwise. In most cases this will not be harmful to the circuit, but it surely won't give you any sort of indication about if it's working properly or not.
If you want to test without risking LEDs, get one or more power resistors of appropriate resistance to simulate the LED load and run the driver against those.
FWIW I bought a bunch of cheap no-name HP LEDs a few months ago (the ones you see on eBay and other places with questionable specs) and I now test against those instead of "valuable" LEDs.
You CANNOT test the output without a load attached - the IC will basically just pass through the input voltage if there's no load to tell it otherwise. In most cases this will not be harmful to the circuit, but it surely won't give you any sort of indication about if it's working properly or not.
If you want to test without risking LEDs, get one or more power resistors of appropriate resistance to simulate the LED load and run the driver against those.
FWIW I bought a bunch of cheap no-name HP LEDs a few months ago (the ones you see on eBay and other places with questionable specs) and I now test against those instead of "valuable" LEDs.
perikaruppan
Member
ok will go in that line then...
and just noted that the power supply that i a have is 48v/7A. when adjusted the min is 40.5v... and in the ZXLD XLS sheet it tells for 40.5V, i can have 1 to 10 LEDs.. so can i just wire up 6 ... all to minimize loss if things go wrong..
after reading a lot on LEDS i know this is not possible as 40.5V on 6 LEDs is a killer.. but what if the chip is capable of adjusting the output based on the load?
and just noted that the power supply that i a have is 48v/7A. when adjusted the min is 40.5v... and in the ZXLD XLS sheet it tells for 40.5V, i can have 1 to 10 LEDs.. so can i just wire up 6 ... all to minimize loss if things go wrong..
after reading a lot on LEDS i know this is not possible as 40.5V on 6 LEDs is a killer.. but what if the chip is capable of adjusting the output based on the load?
TheFishMan65
New member
perikaruppan,
The ZXLD is capable of input of 40.5 volts and driving 6 LEDs, but it is going to dissipate a lot of heat. 6 LEDs has a drop of about 21 volts. So the other 19.5 is dropped by the chip if you are driving at 1 amp then that is 19 watts. If you do that, I would add some power resistors in series with the LEDs to drop some of that voltage.
The ZXLD is capable of input of 40.5 volts and driving 6 LEDs, but it is going to dissipate a lot of heat. 6 LEDs has a drop of about 21 volts. So the other 19.5 is dropped by the chip if you are driving at 1 amp then that is 19 watts. If you do that, I would add some power resistors in series with the LEDs to drop some of that voltage.
