DiY LEDs - How to Power Them

[Banana444]

http://www.arcade-electronics.com/NTE-74-6SG3A-B-p/nte-74-6sg3a-b.htm


Im glad our dumb questions amuse you This fuse is what I want then?

 

[stardustsailor]

Any one know what that means. LOL

It means that when a single LPC-60-1400 driver switches 'ON' for a moment ,a 29 A (at 115 VAC ) inrush current "spike" will be drawn ,towards the driver ..
The driver itself is well protected from that inrush current .(With the use of a Negative coeff Thermistor ,usually ..) .
If you will put a fuse that trips fast ( marked with F in glass fuses ,D or Z or K on circuit breakers ) at 3 A ,the fuse will trip ,as the inrush current is ~x10 times (29 A ) the rated current of fuse ....

It will take a slow tripping fuse (marked T in glass fuses or B/C on circuit breakers ) that it will allow a short inrush
current current of x10 times the fuse's rated current (3 A ) to be drawn for a dt of a sec ,without the fuse to trip/burn ..

...

 

[stardustsailor]

http://www.arcade-electronics.com/NTE-74-6SG3A-B-p/nte-74-6sg3a-b.htm


Im glad our dumb questions amuse you This fuse is what I want then?

For 115 VAC ( like U.S.A ) ,yes .
That's the one ...

Note:
1) Your questions are not dumb .
2) It takes lot more than that ,for me to be 'amused' ..
Usually 3-4 full loaded bowls ,are enough ,though ...

Cheers .

 

[Dloomis514]

It means that when a single LPC-60-1400 driver switches 'ON' for a moment ,a 29 A (at 115 VAC ) inrush current "spike" will be drawn ,towards the driver ..
The driver itself is well protected from that inrush current .(With the use of a Negative coeff Thermistor ,usually ..) .
If you will put a fuse that trips fast ( marked with F in glass fuses ,D or K on circuit breakers ) at 3 A ,the fuse will trip ,as the inrush current is ~x10 times (29 A ) the rated current of fuse ....

It will take a slow tripping fuse (marked T in glass fuses or B/C on circuit breakers ) that it will allow a short inrush
current current of x10 times the fuse's rated current (3 A ) to be drawn for a dt of a sec ,without the fuse to trip/burn ..

...

Awesome, thank you

 

[Nc87]

So there's no point in putting a fuse on the DC side?

Sent from my SAMSUNG-SM-G900A using Rollitup mobile app

 

[Banana444]

Im really wishing I didnt experiment with X when I took electronics 1,2 and 3. I might actually remember something so for that I am dumb. That was along time ago. Most of this stuff make sense and I love learning. I am still awaiting the arival of my artic 11 plus (x2) so I can start assembling my first diy. I dissasembled my old p s 3 to fix a Y L O D. I feel like that was a good warm up to building one of these COBs and I still have half a tube of silver thermal paste.

 

[Banana444]

I have a question about led suppliers. My work has a company that they buy led components designed for in home lighting. They do not sell to the public. Does this compant just get it supplies from places like digikey, mouser, newegg etc. I feel like with my knowledge I could easily cut out a middle man when it comes to certain things like power supplies.

 

[tenthirty]

So there's no point in putting a fuse on the DC side?

Sent from my SAMSUNG-SM-G900A using Rollitup mobile app

Ya, I like to see the smoke escape from a $40.00 cob too!

 

[Tazbud]

I didn't bother with AC fusing on my AC driver, figuring that it's going to drive fine unless all cobs go. It seems to have a list of it's own protections as well. A fuse isn't hard to put in line though, should do it. A mate has his 9 cobs running each from a separate circuit breaker in an normal house style fuse box, neat job.

 

[guod]

a fuse on the AC side is not a bad idea, above 100W per Driver I start to thing about it.
for the rest,,, its build in

the cheap low power Meanwell LPC-20

Universal AC input / Full range
Withstand 300VAC surge input for 5 seconds
Protections: Short circuit / Over voltage*
Cooling by free air convection
Fully encapsulated with IP67 level
Class 2 power unit

wiki-------------------------------------------------------------------------
Class II

Class II symbol
A Class II or double insulated electrical appliance is one which has been designed in such a way that it does not require a safety connection to electrical earth (ground).

The basic requirement is that no single failure can result in dangerous voltage becoming exposed so that it might cause an electric shock and that this is achieved without relying on an earthed metal casing. This is usually achieved at least in part by having two layers of insulating material surrounding live parts or by using reinforced insulation.
-----------------------------------------------------------------------------wiki
*
blockdiagram LPC-20...


btw. no fuse is fast enough to protect a LED against over current.

 

[stardustsailor]

btw. no fuse is fast enough to protect a LED against over current.

..Except maybe ,from another diode used as 'fuse ' ,ain't that right ?

Cheers.

 

[salmonetin]

...or maybe something like this...

http://www.littelfuse.com/products/led-protectors.aspx

http://www.littelfuse.com/~/media/electronics_technical/application_notes/led/littelfuse_open_led_protection_for_led_strings_application_note.pdf

http://www.littelfuse.com/~/media/electronics_technical/application_notes/led/littelfuse_protecting_leds_in_product_designs_application_note.pdf

https://www.speed2design.com/reports/LED_Lighting_Design_Guide.pdf

...or...

http://www.littelfuse.com/products/tvs-diodes.aspx

http://www.littelfuse.com/~/media/electronics/product_catalogs/littelfuse_tvs_diode_catalog.pdf.pdf


http://www.littelfuse.com/~/media/electronics_technical/application_guides/littelfuse_circuit_protection_technology_application_matrix_application_guide.pdf



Saludos

 

[Abiqua]

@SupraSPL @stardustsailor

Wanted to get your guys thoughts, if you don't mind. I hesitate to post this, but I want to retrofit a sewing light with LED. I know I have talkedwith you Supra and that will happen at some point, but now to get in the game, no matter how little it is.

[The light will at least be used to sew some DIY smart pots and bubble bags too!!!! Association]

Light started life as a 13w PL-s...then burnt out and ballast [which has a hole in it] is easily discarded as it is the integrated AC plug as well.

• Want to run a single Vero 13 5000k @ 350 mA with this driver http://www.trcelectronics.com/Meanwell/led-driver-apc.shtml [@guod...but now I hesitate because it is a Class2 type....NG]
• I salvaged this heatsink from a PS2 and the fan is a 35mm12v .12A fan from a small car inverter. [Just a mock-up, most likely neither of these is good option for longer operation......
  • I would rather use an appropriate size passive sink, if it will fit, part of my problem is the mental dyslexia when it comes to calculating heat values and surface area of the sink, I am getting very lost...easy. I just need to be shown...ONCE.
    
  • Also would have to run a small power supply for the fan without a Passive sink.....much harder
• I would like to use the existing case by floating everything and using the pre existing switch.
  
• I need to fuse the switch too, 1A ok?
• Also have a bigger heatsink, that I can cut up for a passive sink?

Yes, the plastic casing is going to rough, but can I make it work? I have about 1-1.25" of depth and a surface area of 4" by 7" roughly. So a bigger passive sink would fit. Then I can mount and make a grill in the top of the light housing [drill]

I was hoping to tuck the single Vero and the Apc-12 into the same housing. Or I can remote mount the driver further along down the handle in a little project box.

Thoughts?

I am ready to buy everything I need online....$30-40 budget.

Hoping to run Molex connector and Wago 222's. The 221's which are smaller are supposed to released soon, so fingers crossed. Already have a power cord too.

THANK YOU!

 

[doctorflux]

Does anyone know how BML has the LEDs in their light engines configured? I am intrigued because they are using a single constant current supply, however are stringing LEDs of very different forward voltages within the fixture. This would typically result in unequal currents across each LED die, potentially overdriving some.

My thoughts are that they implemented some kind of current mirror to keep consistent current within each LED, or are using a small constant current driver IC behind each LED package and setting the drive current individually at each IC (the fixtures are pick and placed to order after all). Does anyone know for sure?

 

[FranJan]

Different forward voltages in a CC series is fine, see the BS240 and a hundred other panels made today in China, it's only a problem if the diodes have a different max amperage and the driver exceeds that. So having a group of 3 volt reds and a group 2.5 volt blues are OK you just have to make sure the driver offers a amperage both can handle plus the minimum voltage the series needs. Maybe they do run some bucks or boosts which justifies their BS prices a bit more but IDK dick about Bitches Makin' Lumens gear really so take my .02 as you will.

 

[nogod_]

How important is power factor correction when selecting a driver?

 

[doctorflux]

Power factor is becoming a big deal, with all lighting over 25W in Europe requiring it. Lots of quality grow lights will likely already have a power factor corrected power supply.

For the grower, power factor correction is important if you have lots of lights and equipment on a circuit, since many devices with bad power factor on a circuit will trip breakers and potentially incur fines with the power supplier.

If it is only a few lights (less than 1500W behind any one utility meter), I wouldn't be too worried. If you are doing DIY LEDs, I'd be more concerned with selecting an LED driver with the proper electrical isolation from mains to avoid potentially deadly shocks if something goes wrong.

 

[Greengenes707]

Is anyone familiar with the cree characterization tool (http://pct.cree.com/dt/index.html)?
I have been going over some specs lately, and a couple things are not quite matching up with the data sheet.
The tools 25*C numbers are right on but their 85*C isn't really matching up with the data sheet. Seems like the tool is based on just 25*C...but still makes me wonder why their figures are so low if the data sheet says it should hold it's efficiency better as temps increase.
Anyone know what's up?

 

[doctorflux]

I took a look at the Cree tool and found pretty good agreement between the tool and datasheet.

First I took the 25C / 350mA test flux from a white bin N4 LED from the XP-E datasheet and got 62 lumens.

Next, look at the 'relative luminous flux vs forward current' chart for white on page 10 of the datasheet. I chose a drive current of 700mA, and found a 175% increase in flux from the test current flux. Calculated to 700mA, I now get 62 * 1.75 = 108.5.

I now need to derate this number for the junction temperature derating curve, which is found at at the bottom of page 8. This chart shows that I will get only 85% of the 25C output of this LED at 85C. I then calculate the final flux (0.85 * 108.5) = 92.2.

Both of these numbers agree well with what I calculated with the tool (see image):

 

[Greengenes707]

I took a look at the Cree tool and found pretty good agreement between the tool and datasheet.

First I took the 25C / 350mA test flux from a white bin N4 LED from the XP-E datasheet and got 62 lumens.

Next, look at the 'relative luminous flux vs forward current' chart for white on page 10 of the datasheet. I chose a drive current of 700mA, and found a 175% increase in flux from the test current flux. Calculated to 700mA, I now get 62 * 1.75 = 108.5.

I now need to derate this number for the junction temperature derating curve, which is found at at the bottom of page 8. This chart shows that I will get only 85% of the 25C output of this LED at 85C. I then calculate the final flux (0.85 * 108.5) = 92.2.

Both of these numbers agree well with what I calculated with the tool (see image):View attachment 3274760

I am referring to the cxa3070 since it's spec sheet has min flux at both 85C and 25C under the bin group. It's the min flux@85*C in the bins that doesn't match up with what is calculated based on thermal droop chart from 25C, which is what I figured the tool was using...
The thing is...they are supposed to be hot binned at 85C...so the real output at 85C. And then the 25C is only calculated...so why is the actually hot binned min flux not being meet??


Using the AB bin and going off the test current of 1925ma...which isn't shown, but 1900ma and 1950ma are so use some imagination...
@25C should be 9130lm...And it is right on the target 9130lm
@85C should be 8500lm...It is well short of the 8500lm...some where between 772lm and 572.3lm of meeting the minimum it was supposed to be hot binned based off.