Was curious to see what experts say about LEDs and their life span. Now, from what I know about sound systems, when you turn up the volume on a set of speakers, let’s say; you’re increasing the current. Does the same thing apply for lights?
Do LED lights differ in this regard? And if you were to use LED lights at a more dim setting, does it have an impact on their longevity at all?
Some additional context would help. An LED can light up a stadium or a smart watch and apples do not equal apples.
Should I assume this is related to the G910, or something else?
Driving an LED at rated voltage and current (typically for white LEDs: 3.2V, 20mA), their expected life is >20k hours.
Overdriving an LED with overcurrent makes them go dimm rather quickly, overvoltage makes them blink once and then they are DEDs (Dark Emitting Diods).
Yeah, I was sort of thinking about how I used my G910. I was super conservative with the LEDs. Only used them when my room was dark. And all my profiles had their lighting at approximately 50%, give or take. Maybe a little more, usually a little less. I didn’t want to run them too high. And honestly, I think it looks better. And it really fucks with my eyes less. When I really focus on them, they can make me dizzy… Seriously. Even in my periph.
Yeah, I was just thinking about the G910 keyboard and how long LEDs would last on something like that, and if you lower brightness of LEDs on said device, would it even make a difference in their longevity?
And was I correct in what I said. I just took what I knew of how the volume works on sound systems. Higher volume = higher current. Is that the case when turning up brightness of LEDs/other lights?
And on another note… is it even possible to REPLACE and install new LEDs in a device like that?
In theory, it would. As most RGB(W) in consumer electronics is done via PWM, it reduces the time the LEDs are at full power.
Picture from the web to show how it works:
More or less, yes. Higher voltage at the same current results in higher power wich translates to volume. Keep in mind current makes it smell and voltage makes it pop.
When you can source 3mm or SMD LEDs that somewhat match the ones in the keyboard, yes. However the mechanical endurance of the switches is much lower than the electrical lifetime of the LEDs.
Well, I wish I understood the diagram. But you said >20K hours. Meaning GREATER than? It doesn’t seem like it’s a whole lot of time. I mean, it’s a LONG time. But on average I would say that I use the lights on my G910 for around 30-40% of the time i’m taking. Most of the time probably less. 20K hours is nearly 2.3 years of running non-stop. Also, almost forgot. The key switches supposedly have a life of 70,000,000 key presses. 50M is approximated at 97 years of usage…
I read that LEDs in industrial applications from the 70s are still in use to this day. Impressive. What makes them so much more burly than what’s used in something like the electronics we use with LEDs?
More than 20 thousand hours.
I trust Vishay’s / Cree’s Datasheets more than I trust Logitech’s marketing department
Lifetime of an LED depends on operating condition and technology (the semi conductor that makes the thing work).
GaAs based LEDs will last forever when driven at spec and not getting hit be reverse voltage.
GaP LEDs are dimm, and that is all I know about them.
Afaik GaN based LEDs are super efficent and fucking bright (allthough, don´t overdo it for too long with them)
Edit:
Big Clive video I have not watched in ages:
I can’t believe there isn’t some keyboard freak that would find out things like this. What exact LEDs were used. But I thought Vishay and Cree make their own LED designs? Or are you talking about their universal LED guidelines for all LEDs?
1 million key presses alone on a single switch is A LOT. That equates to years.
LEDs in a keyboard are more likely to fail because of mechanical issues (using the keyboard) rather than old age. I don’t think I’ve ever seen a failed LED that didn’t fail because of power issues.
I don`t think Logitech makes their own LEDs, they buy them from someone (Vishay or Cree, for example).
Yep
I have!
led’s don’t like too much ripple current
and generators without voltage conditioning circuitry (smaller portable ones) can make led’s go pop quickly.
we set up isolation transformers with our surge suppression gear.
in case the generator is running the electronics and led lighting in the house is safe
what you are looking at in the diagram is the time span that the led remains energized
notice how much wider the peak of the pulse is, at 90% as compared to 10%
the shorter the time span between one on peak and the next the brighter it will be until the pn junction reaches the cascade point and fails
and if its messing with your eyes that badly check into the color temperature and frequency they are driven at.
color temperature has nothing to do with thermal temperature but how the visible light is perceived and usually you need a quality light meter to read it.
too high a temperature can hurt your eyes even if the led’s are dimmed.
Interesting … From my testing LEDs (in my case for room lighting purposes) died either from thermal failure or form voltage spikes, never from ripple current. In fact, I tested OSRAM LEDs with absurd ripple and they did not care as long as voltage was in check. I would like to know more about that failure mode!
I agree with @MazeFrame here. The dimming is eithere done with PWM or by reducing the target current of a constant current source (like on many LED driver chips). Either way lower current increases lifespan but only up to a point. With higher power LEDs you can sometimes increase lifespan by double or more by running them at around 95% -90% of their current rating after that you have diminishing returns (essentially no difference). With lower power LEDs I never could run a test (whithin spec) long enough to make them fail, so you are probably fine either way. (Obviously that depends on the LEDs used and the quality of the power source)
yes, I agree there, not sure however if you can change the driver frequency on the keyboard. Anyway, the driving frequency should be high enough to not be perceptible by the human eye. From my experience a perceptible flickering that strains the eyes can happen from a badly implemented power source. Depending on the design error it can help to either add a small load right after the LED power source or to add a reasonably big, low ESR capacitor.
Source?
They don´t care unless you expose them to reverse voltage or overcurrent or overvoltage. Frequency is a non-issue.
i should rephrase that not so much ripple current but too much of a ripple in the current flow .
an led is a diode and has a reverse and forward bias.
if the current and voltage spike exceeds the reverse bias then you have a cascade failure of a pn junction and they will fail.
unconditioned power can fluctuate dramatically in amplitude. and for an instant can exceed the threshold.
you can often find these issues with power supplies that have taken a surge
while it may not do enough damage to destroy the power supply none the less there may be damage to the electrolytic’s and even if its not visible to the naked eye the power could be slightly unstable.
suspected power supplies should be monitored under load with an oscilloscope. and this will rapidly point out a failing unit long before you get the burnt s#!t in a stick smell
while for a normal computer user it may not cause an issue, But with a power user, gamer, graphics intense programmer unstable power is seriously detrimental.
no power supply ever leaves my shop without a scope and test report!
even those going in the scrap bin are documented.
and reverse voltage! providing that it doesn’t exceed the maximum voltage rating led’s don’t care about that one bit they light or they don’t (dc)
with ac they just rectify the voltage.
here’s a cute experiment.
look up a bridge rectifier and how its constructed
you can make one out of 4 diodes (even led’s)
they will convert ac to dc and its funny to watch low frequency ac converted as the led’s will blink under the forward bias pulse
but you must remember to keep the voltage slightly below the led’s maximum or they go poof.
I guess the catch is, that when you have too high of an inductance, ripple results in voltage spikes, which then causes part failure.
right on the money!
I want to take the time here and summarize for @Prenihility . It can be a bit daunting when we argue about every single edgecase of how LEDs can fail.
TL;DR: Don’t worry about it too much. Quite possibly your LEDs will outlast your keyboard. When you are concerned about longevity before you buy any product, I would recommend to look at user reports that have been using a product for a year or so. There are many factors that influence the lifetime of any electronics product.
LEDs become slightly dimmer over time but they are quite robust and can even be overdriven for short timespans. The number of @MazeFrame of >20k hours is an often found number, but you can commonly find lifespans anywhere from 20k to 50k hours.
About increasing Lifespan (“And all my profiles had their lighting at approximately 50%, give or take.”) Your settings are very conservative. My own testing and the very few parts that show numbers on aging indicate that running much lower than 90% (rule of thumb) of spec does not increase lifetime noticably but lowering from 100% to 90% of spec can more than double it’s lifetime. Keep in mind, that I am talking about LEDs for lighting purposes, so it is possible that you won’t see a difference at all but the the rule of thumb probably still applyes to your keyboard. If it looks better with a dimmer setting then just do what looks best to you.
It is possible that this is caused by high frequency flickering in turn caused by a badly implemented and/or aging components on the LED current source. Was this behaviour always there? Colour temperature could also be the reason, see @Gnuuser s answer.
You can refer to MazeFrames answer. You are correct that higher current means more brightness. These variables are even almost perfectly proportional to each other over wide current ranges (only lower on veeeery low current). There are a few factors that get multiplied in there (quantum efficiency, absorbtion coefficent, leakage current).
Yes, depends on your soldering skills. There are even Keyboards out there with through hole LEDs, those are easier to replace for someone without soldering expirience. SMD components are also manageable, they are just very small, might take a few trys. When it comes to that we can find replacement parts together and give you a soldering crash course 
.
Yes, those are relatively low power signal LEDs with a single colour (single bandgap, without phosphorescent layer). You can find those still and they last essentially forever, slightly different technology. However, when you run modern style LEDs at lower currents/temperatures those can also last essentially forever in the right conditions.
Sorry for the wall of text. 
That was an accident, I swear!
For another point relating to LEDs and keyboards…
The inky time I have personally seen an led die in a keyboard, or several actually, was corsair keyboards. They managed to messed it up so badly that the resulting claim was static discharge from fingers on caps killed the LEDs.
And those cases were extreme. Like 3-4 months and they started to die all over the place and seemingly at random too. Like my F row, numpad and macro pad were some of the first to go while also being the least and in some cases never touched keys.
Other than that I have not heard of LEDs dying in keyboards at all. They usually have staggeringly impressive life times. Even the dodgy cast offs you get on aliexpress live long, if not slightly varied brightness to each other, lives.
This does not sound like LEDs dying but like the transistors/mosfets getting too much gate current.
Would have to take a look at the keyboard (= tear it to bits).