What will happen if LED is getting more current than the max current?

pelagic · Mar 12, 2012

I am thinking to get a 1050 mA driver for the LEDs instead of 700mA, but then XT-E only allows 1000mA max.

so.. what will happen if I give it 1050mA for let say 10 seconds? will it burn?

There's always a brief moment that the dimmer doesn't have any power for 10 seconds when the controller is powered up, the driver will output 103% of the current when the dimmer is off.

Thank you all.

turbo21 · Mar 12, 2012

thats probably enough juice to blow the leds imo

bob

greg0385 · Mar 12, 2012

I think your okay with only 50mA over. I believe 1000mA is 1amp so your .05amps over. The life of the bulbs might be shorten by a small fraction but really a unnotice amount. As long as the volts are correct then you should be okay. IM NO ELECTRONICS GUY AND ITS BEEN 5YEARS SINCE I TOOK ANY CLASSES ON THIS SORT OF STUFF. SO HOPEFULLY SOMEONE WILL CHIME IN THAT MESSES WITH STUFF MORE.
good luck
greg

gmoney243 · Mar 12, 2012

Are you usong constannt current or dimmables? If dimmable you should b able to turn down the amps

pickupman66 · Mar 12, 2012

I would say ZAP and you are buying new LED's. but it will depend on the circuit.

1. what is the voltage on the driver?
2. how many LED's do you have on there?

for instance. for instance, lets say it is 48 volts at 1050ma. this is 50 watts. if you have 18 x 3 watt LED's, that is 2.7 watts each so you are safe. if you ahve 16 LED's on teh string, you will blow them at 100%

pelagic · Mar 12, 2012

I am thinking to build a new fixture, getting a 92V(96W) dimmable driver to power 36 XT-E/XP-E. I will not have the LED at the full power the whole time, it's just when the controller is powered up, there will be few seconds window the driver will be outputting 105% power because the controller is not giving the voltage to dim it.

What you think?

NeveSSL · Mar 13, 2012

10 seconds of 50mA over will likely not result in anything other than really bright LEDs. If it was for any actual length of time, heat would likely become an issue. 10 seconds? Not a chance that's going to cause heat issues at only 50mA over.

Also, its worth noting that the voltage is variable on most of these ballasts. That is how they're able to power a wide range of LEDs. For example, the Meanwell ELN-60-48 adjusts its voltage from 24v to 48v. It does this automatically so it can power from between 8 to 14 LEDs.

Brandon

gmoney243 · Mar 13, 2012

pelagic said:
I am thinking to build a new fixture, getting a 92V(96W) dimmable driver to power 36 XT-E/XP-E. I will not have the LED at the full power the whole time, it's just when the controller is powered up, there will be few seconds window the driver will be outputting 105% power because the controller is not giving the voltage to dim it.

What you think?

going by what lindsey is saying you should be fine then cause 96/36=2.666 watts

pickupman66 · Mar 13, 2012

Yup.. that math works...

Cheng,

what about powering up the controller 1 minute before the drivers come on?

Reef Breeders · Mar 13, 2012

The max I run my leds at is 700ma, and its plenty bright. Past that, you shorten. led life and lose efficiency. It will work, but it may cut 5 years off of your leds, not worth it at all

CJO · Mar 13, 2012

As Greg0835 said, it will shorten the LEDs life, but not enough that you would ever know. Going off memory, the 1A rating is based on the LED's L70- the lifespan at which the LED is as 70% bright as when it was new and is rated at 15,000 hours. The big caveat is that life is with proper thermal management.

anemonekeeper said:
The max I run my leds at is 700ma, and its plenty bright. Past that, you shorten. led life and lose efficiency. It will work, but it may cut 5 years off of your leds, not worth it at all

Technically, you decrease efficiency at pretty much anything above 350mA and lose life at anything over the forward current for the LED (the current needed for it to light).

CJ

greg0385 · Mar 13, 2012

watts=amps x volts, fill in the values

48volts x 1.05amps= 50.4 watts/3watt led=16.8 leds

NeveSSL · Mar 13, 2012

Greg, the amount of LEDs you run is determined by the forward voltage, not the wattage.

For example, some LEDs have a forward voltage of 3.3v, some 3.0v, others 2.8v. Even then it changes with the amount of current you're running. Check out page 4 here for the XT-E data, which we're discussing in this thread: http://www.cree.com/products/pdf/XLampXT-E_ROY.pdf

The math on calculating the current and voltage on these LEDs is not quite as simple as good ole PIV would lead you to believe. All of the values are relative.

Brandon

greg0385 · Mar 13, 2012

My point is if you have close to 16-17 leds then it be perfect. 12-15 leds you overdriving the leds. 17-20 leds you be underdriving the leds.
Seems like using a icecap 660 overdriving my t5s to 80watts instead of 54watts. I lose life of the bulb but i get more par from the bulb.

Remember i have no knowledge of leds and forgot almost everything about electronics, im at the office and im bored so im just speaking my opinion to kill some time. Guess its solitaire time!

NeveSSL · Mar 13, 2012

I understand what you're saying, but there's one important thing missing... these drivers automatically adjust their voltage to the amount of LEDs on the string. So if you have 10 or 14 LEDs, it drives them the same and auto-adjusts its voltage to make them work.

So you don't have to worry about overdriving your LEDs on voltage. These systems are a bit backwards compared to most things, which is where most people are use to voltage remaining the same and current changing (such as the outlets in your home). LEDs are constant current, so the current stays the same and the voltage changes. This is also why you need to use drivers and you can't just connect them to a power supply. Power supplies are the conventional constant voltage, variable current, just like house electricity.

I'm only mentioning these things so people can better understand how our DIY LEDs work. But now I need to get back to work. Haha!

Brandon