led driver question

[oreo54]

The more LED's you run in series the higher the forward voltage is and the more chance at shorts, solder breaks, thermal inrush and other issues. This is how you increase the chance of burning out LEDs.

Multiple Parallel runs help keep the voltage low. While you have the issue of possible parallel leg failover sending too much current to the working legs just don't design it that way and leave yourself some breathing room. If one leg fails and sends all the current to 2 or 3 other legs there should be enough current head room so those legs can handle it for awhile. This is the biggest reason you don't drive LEDs at max.

High voltage + DC + DIY = bad. 50volts of Cree XPG3s in a single series driven hard will knock you on your butt before the driver cuts it off. Been there - done that. Those 50volts of LED distributed across several parallel legs of ~18 volts are much safer and will yield less chance of solder jumps and shorts. MeanWell has any possible voltage and current combination of driver out there, so that part is a non issue.

Thing is, unless you need 10v analog or pot dimming might as well go LDD-HW's and a power supply.
Last times I priced it using monolithic a/dc drivers vs multiple LDDs and a power supply, the cost is fairly equivalent.

As to cheap ldd dimming a modified $3 dimmer and a wall wart (or not if the power supply you need is between 9-24V)
$5 and a wire from the gate of the internal mosfet for a 5V PWM signal.
USUALLY can find them for like $2 each from China inc. shipping

Manual Dimmer Switch for LED Strip Light, 12V 8A Mountable with Terminals | eBay

Max Load: 8A (96W).

www.ebay.com

 

[Steven Garland]

So guys,I got 2 of these Osram drivers from work. These would work for a small fixture right ?

 

[oreo54]

50 Watts worth each.

 

[Steven Garland]

50 Watts worth each.

I thought so,I just wanted to make sure. Since they are 400-1400mah,I know I can barely crank them up before things go pop lol.

 

[oreo54]

I thought so,I just wanted to make sure. Since they are 400-1400mah,I know I can barely crank them up before things go pop lol.

Well there is the catch.. They are programmed using an Osram "tool" and Windows..
400-1400mA is in the programming range.
you may need to do some VOM-ing on expendable diodes..
Not sure what their startup default is set at.

https://media.osram.info/media/img/osram-dam-2310558//User_manual_OT_Programmer.pdf

 

[Steven Garland]

@oreo5457 so some old diodes and a volt meter see whereabouts I am on current then ?

 

[oreo54]

Well it's probably in the manual.
30w ones factory default is 700mA.

Do you know it was programmed at work?
The mA out is really the important part.

 

[Steven Garland]

Well it's probably in the manual.
30w ones factory default is 700mA.

Do you know it was programmed at work?
The mA out is really the important part.

I do not,it was powering a bank of SMD's about 4ft long,they were used as temp lighting in new construction.

 

[oreo54]

I do not,it was powering a bank of SMD's about 4ft long,they were used as temp lighting in new construction.

Sounds like it's time to get the ampmeter out. 2A minimum range. Probably do need a diode load I THINK. Enough cheap chips to get to minimum voltage. Or a cob that can take 1400 mA.
10v minimum 55max

Use led plus minus think the other one is for programming see writing on driver. A guess but should be right.

 

[Steven Garland]

So I have some aluminum flat bar 1/8" thick to be exact,about how many leds could this handle ? I need to mount 4-5 to supplement my prime 16hd and really dont wanna get any more.

I have about 4ft of it,could I cut 2 pieces and glue them together to get it more efficent ?

 

[oreo54]

So I have some aluminum flat bar 1/8" thick to be exact,about how many leds could this handle ? I need to mount 4-5 to supplement my prime 16hd and really don't wanna get any more.

I have about 4ft of it,could I cut 2 pieces and glue them together to get it more efficient ?

Well heat sinks are figured on surface area mostly.
Putting 2 together doesn't accomplish much relatively speaking..

Frames like this have run for years w/ drive currents from 700 -1000mA.
Does depend on the diodes though. Cheap flea bay ones can die relatively easy after about a year or so.
That said, mostly white ones.

Bars may reach 120F max.
Heat transfer from diode to star to aluminum bar is important.
I've known some to just glue "eggs" to the bars (no star board) and have better long term success w/ cheap diodes.
Need to watch the wires though..

 

[Steven Garland]

Well heat sinks are figured on surface area mostly.
Putting 2 together doesn't accomplish much relatively speaking..

Frames like this have run for years w/ drive currents from 700 -1000mA.
Does depend on the diodes though. Cheap flea bay ones can die relatively easy after about a year or so.
That said, mostly white ones.

Bars may reach 120F max.
Heat transfer from diode to star to aluminum bar is important.
I've known some to just glue "eggs" to the bars (no star board) and have better long term success w/ cheap diodes.
Need to watch the wires though..

Well I have 500mah drivers,so they current won't be too high. Its 1.5x 1/8" so do you think 4-5 diodes (Semi violets and sunplus royals) would get too hot at .5 amp or is that good enough to run ?

 

[oreo54]

Well I have 500mah drivers,so they current won't be too high. Its 1.5x 1/8" so do you think 4-5 diodes (Semi violets and sunplus royals) would get too hot at .5 amp or is that good enough to run ?

I'd be fine w/ it ....but that's me
Semis have a shorter lifespan anyways, regardless if cooling.
Diodes > 2" in center run at 1.5-2w don't seem problematic. That said 2-10 SQ " / watt is the "standard" for passive cooling
But what fun is that

 

[amirk48]

hi guys
the LEDS are in (royal blues for now)
these are all 3-up, can anyone tell me what is the correct way to solder them in a series?

thanks!

 

[Steven Garland]

simple,since there are jumpers for the other 2 leds these will be solder your positive and negative in corresponding order and all 3 leds will power up.

Example: positive from the driver to the positive on the led then start. Negative to positive,positive to negative ect ect. Then your last led negative goes to your neg on your driver.

Did you get the 3ups from LedSupply for $20 ? StevesLeds would have been cheaper at I think $9.99 or $10.99 each for Luxeon Rebel ES 3ups.

 

[amirk48]

so like this?

yes leds from ledsupply but i paid 9.97$ per one not 20$

 

[stefanm]

so like this?

yes leds from ledsupply but i paid 9.97$ per one not 20$

Correct on the series wiring.

 

[amirk48]

thanks!

 

[amirk48]

hello again everyone

royal blues are done and working, now off to the cool whites
i want to use 12X cree XT-E2 cool white leds

Cree XLamp XP-E2 White LED

www.ledsupply.com

the HLG-C driver i used for the royal blue only go down to 60W, way more than what i need.
i was thinking maybe i could save some money and space going with a smaller one

can anyone direct me to a driver thats a good size for the whites?

i am running them with this pot so it needs to be compatible with 1-10v dimming

Cased Potentiometer with Knob

.

rapidled.com

thanks!

 

[enocorecom]

To give you an idea of the size these are my lights I built. They are 6in by 6in with 5 dimmable channels

Is that a Mean Well LRS-350 power supply?