Homemade LED DRL

[2009Prius]

I am slowly gathering info and parts to make a pair of small LED DRLs for my Prius. I am not aiming for very high brightness so I figure a cluster of narrow angle 5mm LEDs would do - something similar to this (a lousy product by the way)
http://www.dealextreme.com/details.dx/sku.5150
but more LEDs and cleaner lens. In this way I avoid having to deal with drivers, optics and heatsinks associated with high power LEDs and also minimize power consumption.

I am tapping into the washer motor 12V source and wondering about the back EMF and other voltage spikes. I also don't want bad things happen if the power cables were connected backwards. So I am thinking

1. Connect a fast diode in series with the LEDs
2. Connect a bidirectional TVS diode in parallel with the LEDs

Is this OK? Overkill? Not enough? Please comment. Thanks very much! 🙂

 

[Alaric Darconville]

The Prius already HAS DRLs, right?

If you want to move away from a headlamp based DRL, try a turn signal DRL module instead.

Trying to make your own DRLs will result in a non-functioning product. Sure, it may light up, but it most likely won't meet the requirements for DRLs.

 

[2009Prius]

The Prius already HAS DRLs, right?

Canada maybe, not in the US.

If you want to move away from a headlamp based DRL, try a turn signal DRL module instead.

LEDs look better though.

Trying to make your own DRLs will result in a non-functioning product. Sure, it may light up, but it most likely won't meet the requirements for DRLs.

There is no requirements on DRLs in the US that I know of.

Any comments on my original question?

 

[Diesel_Bomber]

There is no requirement to have DRL's in the US, but if implemented there most certainly are legal requirements they must meet. Cobbled together home-built DRL's will be no more legal than cobbled together home-built headlights.

Answering your original question, I would buy a ready made off-the-shelf LED driver and be done with it.

 

[-Virgil-]

There is no requirements on DRLs in the US that I know of.

Right. If they're installed, however, they must conform with the design, construction, and performance requirements contained in Federal Motor Vehicle Safety Standard 108. See SAE J2087 (expensive...contains the design, construction, & performance requirements for DRLs in North America), CMVSS 108 s.44 -- free, Canadian DRL regulatory text. Refers to SAE J2087, so it's not a workaround for the costly SAE document. US FMVSS 108 is substantially identical; differences are that fog lamps are not allowed as DRLs, and DRLs are permitted rather than required (if installed they must conform; the fact they're not required does not mean they're unregulated and does not mean it's OK to use any ol' lamp you decide is a DRL) -- and ECE R87 (free; contains the design, construction, & performance requirements for DRLs everywhere else in the world except North America. Substantial overlap with NA DRL specs; axial intensity range is 400 to 1200 cd in ECE, 500 to 3000 cd in NA except high beam DRLs can have up to 7000 cd. ECE DRL must be white, NA DRL can be white, yellow, or amber.) This is not E-Z kid stuff; the design/construction/performance requirements are stringent and specific for the same reason that is true of headlamp requirements, turn signal requirements, brake light requirements, etc.: these are safety devices, not toys or fashion accessories.

Perhaps you'd like to put on a set of these or these.

 

[Alaric Darconville]

Is this OK? Overkill? Not enough? Please comment. Thanks very much! 🙂

Comment: It's not OK. You're welcome.

Perhaps you'd like to put on a set of these or these.

Wowsers... 144 Pounds Sterling (currently about $218 USD) for one, $377 USD for the other.

... try a turn signal DRL module...

$42 USD....

That DRL turn signal module looks better all the time 🙂

Now that I think about it, Toyota makes a telling gesture about their belief in the effectiveness of DRLs as safety items-- they don't equip them on the Prius because the fuel savings seems to outweigh any safety benefit of DRLs. (Also, when you note that GM has received dispensation from the EPA to disable DRLs for the purpose of fuel economy testing, you'll see even GM doesn't believe they have a negligeable impact on fuel economy, despite them telling consumers that.)

 

[Diesel_Bomber]

I equipped all of my vehicles with something similar to the turn signal DRL that Mr. Darconville mentioned and received an insurance discount. I don't remember how big the discount was, but it paid for the DRL modules within a year. You might check with your insurance company and see if something similar is available for you.

 

[2009Prius]

Thanks everyone! I learned a lot. 🙂

 

[2009Prius]

What if I don't call it a DRL? Say just call it decoration lighting. Are there regulations for decorations? even bumper stickers?

 

[Art]

What if I don't call it a DRL? Say just call it decoration lighting. Are there regulations for decorations? even bumper stickers?

Day Running Lights.

Funny thing is that in my country you are not allowed to have DRLs unless your car comes from factory with it. :ironic:

 

[-Virgil-]

What if I don't call it a DRL? Say just call it decoration lighting. Are there regulations for decorations? even bumper stickers?

It does not matter what you call it, and it does not matter if you (or a manufacturer) labels it "For Off-Road Use Only". Non-mandatory lighting equipment must still conform to applicable regulations (e.g., if it faces front it may only produce white, yellow, or amber light), and is prohibited from interfering in any way with the effective function of mandatory lighting equipment. That last bit is not so easily dismissed as it might sound; obviously if you mount an accessory light so it blocks part of the turn signal, that's interference, but interference can also be caused by lights causing glare or creating an ambiguous signal image or otherwise screwing with the visual presentation of the car's mandatory lights.

 

[2009Prius]

Right. If they're installed, however, they must conform with the design, construction, and performance requirements contained in Federal Motor Vehicle Safety Standard 108. See SAE J2087 (expensive...contains the design, construction, & performance requirements for DRLs in North America), CMVSS 108 s.44 -- free, Canadian DRL regulatory text. Refers to SAE J2087, so it's not a workaround for the costly SAE document. US FMVSS 108 is substantially identical; differences are that fog lamps are not allowed as DRLs, and DRLs are permitted rather than required (if installed they must conform; the fact they're not required does not mean they're unregulated and does not mean it's OK to use any ol' lamp you decide is a DRL) -- and ECE R87 (free; contains the design, construction, & performance requirements for DRLs everywhere else in the world except North America. Substantial overlap with NA DRL specs; axial intensity range is 400 to 1200 cd in ECE, 500 to 3000 cd in NA except high beam DRLs can have up to 7000 cd. ECE DRL must be white, NA DRL can be white, yellow, or amber.) This is not E-Z kid stuff; the design/construction/performance requirements are stringent and specific for the same reason that is true of headlamp requirements, turn signal requirements, brake light requirements, etc.: these are safety devices, not toys or fashion accessories.

Perhaps you'd like to put on a set of these or these.

Thanks for pointing out the references. SAE J2087 specifies the light intensity distribution which is indeed "not E-Z kid stuff" especially if I want to make them out of 5mm LEDs. However the actual regulation 571.108 does not reference SAE J2087 and all it asks for is

Has a luminous intensity not less than 500 candela at test point H-V, nor more than 3,000 candela at any location in the beam

Looks like I am home free on this one. 🙂

 

[Alaric Darconville]

Wouldn't that also need to pass certain chemical resistance tests, exposure tests, abrasion resistance tests, ec?

 

[-Virgil-]

Thanks for pointing out the references. SAE J2087 specifies the light intensity distribution which is indeed "not E-Z kid stuff" especially if I want to make them out of 5mm LEDs. However the actual regulation 571.108 does not reference SAE J2087

You are assuming that FMVSS 108 is clearly written and easily understood. Unfortunately for everyone, that is not a good assumption. What the statute actually says, in S5.5.11(a), inter alia, is:

****
Any pair of lamps on the front of a passenger car, multipurpose passenger vehicle, truck, or bus, whether or not required by this standard, other than parking lamps or fog lamps, may be wired to be automatically activated, as determined by the manufacturer of the vehicle, in a steady burning state as daytime running lamps (DRLs) and to be automatically deactivated when the headlamp control is in any "on" position, and as otherwise determined by the manufacturer of the vehicle, provided that each such lamp has a luminous intensity not less than 500 candela at test point H-V, nor more than 3,000 candela at any location in the beam when tested in accordance with Section S11 of this standard (and) is permanently marked "DRL" on its lens in letters not less than 3 mm high (...)
****

Portions of the text are bolded to give you some pointers to aspects that call for design and testing a great deal more specific and stringent than just "Yeah, that's about the right intensity range".

Furthermore, S5.1.2 states, inter alia:

****
S5.1.2 Plastic materials used for optical parts such as lenses and reflectors shall conform to SAE Recommended Practice J576 JUL91 (...) After the outdoor exposure test, the haze and loss of surface luster of plastic materials (other than those incorporating reflex
reflectors) used for outer lenses shall not be greater than 30 percent haze as measured by ASTM D 1003-92, Haze and Luminous Transmittance of Transparent Plastic (...) After exposure to the heat test as specified in subparagraph (f) of this paragraph, and after cooling to room ambient temperature, a test specimen shall show no change in shape and general appearance discernable to the naked eye when compared with an unexposed specimen. The trichromatic coefficients of the samples shall conform to the requirements of SAE J578c, Color Specification for Electric Signal Lighting Devices, February 1977.
****

That's a materials durability and environmental performance standard that must be met by all plastic lighting devices on a car, not just those specifically required.

There are additional provisions of FMVSS 108 that apply to non-required lights, but this ought to be enough to give you the idea that "Nope, I don't see a ref to J2087, so I'm all set!" is not correct.