LED lights

_QQ_ · Jan 23, 2017

@fuzzy1, since that rather rude dude from Luxemburg is simply not responding properly:

In all of Yurp DRLs are sufficient in case any daytime light is mandatory (like in Poland, Italy and more). Low beams in stead when not equipped with DRL.
In quite a few countries the use of DRL (or low beams) is not (yet) compulsary. (Including, btw, the OP's country and Germany, unlike his suggestion; in those countries it is 'recommended')

All new cars sold since 2011 are required to have DRL. Since 2015 also red ones on the back of the vehicle.

Just thought I'd straighten this thing, since he seems to advocate 'alternative facts'

Cheers

fuzzy1 · Jan 24, 2017

Piotrus Pan said: ↑

It has "forthcame" about 10 posts ago.
LED lights | PriusChat

Again, if companies can make LED's more efficient by pulsing, companies will do it and there nothing you can say that will change that.
Also, when you talk about graphs and not present them, then natural reaction is that you are pulling them out of your nice person.
If you would stop being such a douche, maybe people would try to listen to you.
Smugness is not helpful, feel free to mute/ban me or what ever, you are not a helpful person.
Click to expand...

My old databooks from the 1970s and 80s are long gone or deeply buried in my closest. I will not waste any effort digging up the retained copies for someone with the above attitude.

From an old website I used to follow: Pulsing LEDs to make them look brighter?

Most LEDs have maximum efficiency at currents near or somewhat over 20 mA. There are some exceptions - gallium phosphide red (low current red or "697 nm" red), old type silicon carbide blue, and most InGaN/GaN blue, blue-green, green, and white LEDs. These specific types are most efficient at lower currents.

So back to why pulsing an LED can increase its efficiency?

... But those old fashioned deep red gallium arsenide phosphide LED dice have efficiency varying with current and have efficiency maximized somewhere around 40-100 mA per die. The LED die will make a lot more light if it gets 50 mA pulsed at a 4 percent duty cycle than with steady DC of 2 mA.
Click to expand...

Note that back then, most LEDs were thermally limited to around 20 mA DC. Higher currents required pulsing to use their best operating point without overheating.

Now, move up to more modern times, where luminosity and overall efficiency have vastly increased, but efficiency droops at higher currents.
The amazing progress of LEDs, in one chart - Vox
Proved: Why LED efficiency drops at high current
Light-emitting diode - Wikipedia
http://www.digikey.com/en/articles/techzone/2011/oct/identifying-the-causes-of-led-efficiency-droop
Pulsing is still a valid method for control and dimming, but it no longer improves luminous efficiency.

Piotrus Pan · Feb 6, 2017

fuzzy1 said: ↑

My old databooks from the 1970s and 80s are long gone or deeply buried in my closest. I will not waste any effort digging up the retained copies for someone with the above attitude.
Click to expand...

You barge in to the conversation absolutely not knowing why I showed him the circuit in the first place asking for information already given and playing the all knowing ...
Like I said, you can shove your help up yours sorry, self unaware person.

QuantumFireball · Feb 7, 2017

fuzzy1 said: ↑

But DRLs have been around since before white LEDs were developed. On most North American cars with DRLs, the function was originally (and usually still is) produced by normal high beams operated at reduced voltage (and power). Some DRLs may be true low beams.

Do your country's laws very specifically and narrowly require low beams? Or is the language broad enough to merely require a certain level of daytime visibility, giving designers flexibility in how this is achieved and allowing for new innovations to be introduced? The later ought to allow you to use any of the DRL varieties commonly used in other countries.
Click to expand...

In the EU since 2011, new cars are required to be fitted with DRLs that are functionally separate from any other lights and need to be compliant with UNECE Regulation 87: https://www.unece.org/fileadmin/DAM/trans/main/wp29/wp29regs/2013/R087r3e.pdf
Daytime running lamp - Wikipedia

Requirements for usage differ between countries in the EU though. The US is one of the few countries that does not comply with UNECE automotive lighting standards, so lights often differ significantly on US versions of cars. The DRLs on mine (2012 post facelift) look like a square grid of LEDs above the indicators on the front bumper.

Tideland Prius · Feb 7, 2017

What the hell happened to this thread? You guys were talking nicely until the end of page 1.

Robert Santana · Feb 12, 2017

I'm considering these as well. I'm still trying to source the parts for the upgrade though. The ballast seems to be an issue

LED lights

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