Need help troubleshooting LED build

CliftonArbogast · 01/01/2012, 11:02 AM

Got it powered up yesterday and works well. . . almost. Whites, are flawless and work like i want.

The blue strands ( all separate with independant drivers) only pull half the max amps when i have 10 VDC in. I have same wireing on Blues as the whites and ALL LIGHTS work when each strand is fired individually or with all on. no shorts nothing funny just not at full power.

the drivers im having trouble with are LPF-40D-48 Meanwell one is bad and wont put up the correct voltage ( he is going back) The other two only put up ~400 mA at full. and i tried different drivers on different strings of LEDs and they are the same no matter what strand of LED they are on. ( including broken Driver)

Details on blue strands i have 16 LEDs all XTE-RB. Each strand is independant and has a one ohm resistor.

I can vary the blue and the white the 10V DC in POTs and they go up and down in amps and brightness so i think thats working fine. any Suggestions, Clues or Questions. I cant think of any reason the driver would put up correct voltage but only half max amps

I NEED MORE POWER!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

BIG SHARK · 01/01/2012, 11:21 AM

Clifton you said your blue strands are independent does that mean the are all home runs back to the block because form my experince with leds (not to much lol) they have a wire lenght max that will cause a drop in power from the drive say only 10' of total wire can be used from the driver to lamps. just like head height on pumps. Try putting your lamps in series and one home run back to the driver see what that does. i had the same problem when we installled led strip lights for a guy at work i could only run so many feet of wire form my driver to my lts and watch wire size voltage drop is big when talkling dc current . go to the next wire gauge hire see if that helps. hope i helped you out with this info and good luck

CliftonArbogast · 01/01/2012, 02:02 PM

Big Shark, each curcuit is five feet up to first LED, 6 feet through all then five more back to negative side. in total about 16 feet. Im not totally sure about electricity but i would think what your talking about would max the powersupply without max light since the losses due to the wire size would be more than allowable.

On a hunch ( and since both curcuits are 48 volt) i hooked a blue power supply up to a white run of LEDs. Measured 48 volts and 800 mA so the power supply can do it. ( i am guessing the LEDs are not asking for that much draw which i am confused maybe I missed something with the draw of the XTEs but thought i did the math right can anyone confirm correct amps and volts for 16 XTE RBs for me. I got 48 volt and 1000mV, the 800 i bought is for safety and longer life.

radicaltimes · 01/01/2012, 06:33 PM

Rapid Led told me that you could run 15 of these leds on the 48 driver. Also what is the resister installed for

BIG SHARK · 01/01/2012, 10:07 PM

Did you hook up the blue leds to the driver that was running the white leds and ge the same output from the blue leds. then hook the white one up to the blue driver and see if the light is the same for the white one on bothe drivers that will rule out the drivers. then you can concentrate on the blue leds themselves. can you take a picture of the specs on the driver that will help me determine alot about the led install. bigger wire gauge will not boost voltage it just has more area for the power to run without "line loss" bigger is better when it comes to electricity. leds typicaly only draw between 1-3 watts which at 120 volts is .025 amp draw. its not the draw somethings wrong with A- the drive do test to rule this out B- wire size to leds. hope this helps let me know what you find more info better i can narrow down

CliftonArbogast · 01/02/2012, 04:34 PM

Ok i tried running the blues off a white driver. . . strand wont pull more than 400mA even when the white strand was pulling more, so I know its not the driver, so i used 12 AWG and ran the lengthe up to the plug with aligator clips that are thinner but short. Still wont pull more amps???

These are what i have http://www.cree.com/products/pdf/XLampXT-E_ROY.pdf

Driver Details are here
http://www.meanwell.com/search/LPF-40D/default.htm
I have the -48 model.

The resistor is for checking the amps without unwireing. I have 16 on these series, do i have one too many?

CliftonArbogast · 01/02/2012, 05:37 PM

We figured it out. One too many LEDs. . . not enough forward voltage to get up to full amp draw. I can jumper around one, and the rest of the LEDS go to full power. And are brighter than the 16. Thanks for your help Big Shark and RadicalTimes, i gotta do more soldering!

BIG SHARK · 01/02/2012, 06:15 PM

Glad you got it fixed

01/02/2012, 04:34 PM	#6
CliftonArbogast Registered Member Join Date: Dec 2010 Location: Houston TX (south side) Posts: 165	Ok i tried running the blues off a white driver. . . strand wont pull more than 400mA even when the white strand was pulling more, so I know its not the driver, so i used 12 AWG and ran the lengthe up to the plug with aligator clips that are thinner but short. Still wont pull more amps??? These are what i have http://www.cree.com/products/pdf/XLampXT-E_ROY.pdf Driver Details are here http://www.meanwell.com/search/LPF-40D/default.htm I have the -48 model. The resistor is for checking the amps without unwireing. I have 16 on these series, do i have one too many? Last edited by geo; 03/22/2012 at 06:32 PM.

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01/01/2012, 11:21 AM	#2
BIG SHARK Registered Member Join Date: Dec 2011 Location: YORK, PA Posts: 6	Clifton you said your blue strands are independent does that mean the are all home runs back to the block because form my experince with leds (not to much lol) they have a wire lenght max that will cause a drop in power from the drive say only 10' of total wire can be used from the driver to lamps. just like head height on pumps. Try putting your lamps in series and one home run back to the driver see what that does. i had the same problem when we installled led strip lights for a guy at work i could only run so many feet of wire form my driver to my lts and watch wire size voltage drop is big when talkling dc current . go to the next wire gauge hire see if that helps. hope i helped you out with this info and good luck

01/01/2012, 02:02 PM	#3
CliftonArbogast Registered Member Join Date: Dec 2010 Location: Houston TX (south side) Posts: 165	Big Shark, each curcuit is five feet up to first LED, 6 feet through all then five more back to negative side. in total about 16 feet. Im not totally sure about electricity but i would think what your talking about would max the powersupply without max light since the losses due to the wire size would be more than allowable. On a hunch ( and since both curcuits are 48 volt) i hooked a blue power supply up to a white run of LEDs. Measured 48 volts and 800 mA so the power supply can do it. ( i am guessing the LEDs are not asking for that much draw which i am confused maybe I missed something with the draw of the XTEs but thought i did the math right can anyone confirm correct amps and volts for 16 XTE RBs for me. I got 48 volt and 1000mV, the 800 i bought is for safety and longer life.

01/01/2012, 06:33 PM	#4
radicaltimes Registered Member Join Date: Sep 2008 Location: Columbus, Oh Posts: 274	Rapid Led told me that you could run 15 of these leds on the 48 driver. Also what is the resister installed for

01/01/2012, 10:07 PM	#5
BIG SHARK Registered Member Join Date: Dec 2011 Location: YORK, PA Posts: 6	Did you hook up the blue leds to the driver that was running the white leds and ge the same output from the blue leds. then hook the white one up to the blue driver and see if the light is the same for the white one on bothe drivers that will rule out the drivers. then you can concentrate on the blue leds themselves. can you take a picture of the specs on the driver that will help me determine alot about the led install. bigger wire gauge will not boost voltage it just has more area for the power to run without "line loss" bigger is better when it comes to electricity. leds typicaly only draw between 1-3 watts which at 120 volts is .025 amp draw. its not the draw somethings wrong with A- the drive do test to rule this out B- wire size to leds. hope this helps let me know what you find more info better i can narrow down

01/02/2012, 05:37 PM	#7
CliftonArbogast Registered Member Join Date: Dec 2010 Location: Houston TX (south side) Posts: 165	We figured it out. One too many LEDs. . . not enough forward voltage to get up to full amp draw. I can jumper around one, and the rest of the LEDS go to full power. And are brighter than the 16. Thanks for your help Big Shark and RadicalTimes, i gotta do more soldering!

01/02/2012, 06:15 PM	#8
BIG SHARK Registered Member Join Date: Dec 2011 Location: YORK, PA Posts: 6	Glad you got it fixed