TrailBeast
AKA Mopars4us on Youtube
Post removed for possible safety issues, sorry.
Incandescent to LED rear lights
- Thread starter TrailBeast
- Start date
-
slantsixdan
=..=
I hate to throw a wet blanket, but this what you have done is not a safety upgrade at all -- it's a downgrade. To make a safe, good-performing LED lamp for an older vehicle application is not an impossible task by any means, but it is not a simple or trivial one, and "LED bulbs" like the ones you installed don't (ever) result in a lamp that gives adequate safety performance. Not even when measured according to the standards that were in place in 1971. There are critical safety performance issues involved with a car's brake/tail/turn lights; they need to work in specific ways to do their job effectively and keep you safe on the road. Just looking at a homemade or aftermarket brake light and saying "Yup, looks nice and bright" isn't good enough. Before anyone spends money or time on this, see here and here and (more technical stuff) here. See also here and here.
The '71-'73 Dart brake/tail lights are not very strong performers in stock form, but there are various ways of (genuinely) improving them substantially. It has been done, and I understand Spaghetti Engineering has (or will soon have) a good LED conversion for this application. Simple basic maintenance (see here) including cleanup and assuring proper ground will go a long way. Better bulbs are readily available. My own upgrade on a '71 is described here — although US regulations still permit rear turn signals to be red, the US DOT's latest research shows you're up to 28% less likely to be struck from behind if they're amber, and UMTRI research shows following drivers react faster and more accurately to your brake lights if your rear signals are amber rather than red.
The '71-'73 Dart brake/tail lights are not very strong performers in stock form, but there are various ways of (genuinely) improving them substantially. It has been done, and I understand Spaghetti Engineering has (or will soon have) a good LED conversion for this application. Simple basic maintenance (see here) including cleanup and assuring proper ground will go a long way. Better bulbs are readily available. My own upgrade on a '71 is described here — although US regulations still permit rear turn signals to be red, the US DOT's latest research shows you're up to 28% less likely to be struck from behind if they're amber, and UMTRI research shows following drivers react faster and more accurately to your brake lights if your rear signals are amber rather than red.
TrailBeast
AKA Mopars4us on Youtube
I see that you are, and have been for some time a lighting aficionado.
That's cool, and I respect it.
But,,, I dont want ambers on the rear (personal thing I guess) even though yours do look very nice and I could see how some might like them better.
Both times I got rearended I was sitting with my foot on the brakes.
My main point here was just to show anyone interested how it can be done cheaply with an angled socket and not hurt the original equip.
The results were very likable for the 14 bucks and an hour of time.
MUCH brighter from straight behind, and the lens disperses the light to the sides but not as much as incandescants. (you are right about that)
slantsixdan
=..=
Professional, actually. I am an appointed member of the National Academy of Sciences Transportation Research Board Visibility Committee, the Society of Automotive Engineers' Lighting Committee, and several other relevant bodies. I'm also the Global Editor of the automotive lighting industry's trade journal.
And that's the problem — you have reduced the safety performance of your brake lights, which is not a wise or smart thing to have done, because it increases the likelihood of you getting injured and your car getting damaged.
HawaiiDuster
Well-Known Member
Hey Slantsixdan, are you the "Daniel Stern" Dan? If you are, I've been using info off your site for years. Just thought I'd ask cause it only now started to click in my head :tongue3:
TrailBeast
AKA Mopars4us on Youtube
Damn dude, I hope you have that typed somewhere that you can copy and past it when you need it.
Seriously though, I guess I don't really understand your insistance about it, since they are so obviously so much more noticable now than they were.
I'm open to the posibility that I'm ignorant on the subjects of illumination engineering, photon physics, and molded plastic refraction characteristics, but I'm no noob either.
"40+ years automotive and heavy equipment mechanic, 20 year owner/mechanic automotive repair facility, ATRA certified, BMW, Mercedes, Volvo, and stickshift trans certified, complete 4x4 drivetrain certified through ASA, ex forman trans builder for Aamco, own/tech a computer service and repair business.
DAMN I need to have that where I can copy and paste it!
Point is I don't doubt your knowledge or abilities Dan, just didn't realize that I was going to open a can of worms about it with anyone.
In your honest oppinion I'm sure you would rather I removed the post for safety purposes then?
Never mind, I know the answer to that.
I "assume" he is too, but we'll see (pun intended) LOL
slantsixdan
=..=
Yep, that's me. Glad you like the site!
abodyjoe
Well-Known Member
hemitheus
19? Plymouth Scampenstein
slantsixdan
=..=
Naw. I almost never trot-out my affiliations like that. Probably shouldn't have this time, either. But I type over 110 words/minute!
Because the lights and reflectors on every car, including yours, are there for my safety as much as yours. They're interactive safety devices; they are the means by which drivers communicate to other drivers so those other drivers can adjust accordingly. If this were something that affected only you, I wouldn't be so insistent about it, since your choice wouldn't degrade my safety. ("my" means everyone else on the road in your vicinity)
From straight behind, subjectively they may be more conspicuous, but:
1. You and I both agree they're less noticeable off-axis, and that translates directly to a greater likelihood of being hit and knocked out of lane because the guy in the next lane didn't see your brake lights.
2. You're not wrong, in one sense, when you say they're more noticeable. LEDs come to full intensity faster than filament bulbs, especially when there's voltage drop in the circuit to the filament bulbs. The brake lights come on quicker, is what that means, and that's undoubtedly good. BUT, the intensity is nowhere near high enough. I've (formally) tested a fair number of brake lights that have been retrofitted with these kinds of "LED bulbs" you used, and not a single one of them has ever come close to meeting the minimum requirements for the brake light function -- not even the old 1971 standard. Most of them even fail the much dimmer tail light function; central intensity on axis is okeh but angle of distribution isn't even near adequate.
That's all it is. I don't mean to mock, deride, belittle or dismiss you. Most people think of a car's lights as "they work" or "they don't work" if they think about them at all. Most mechanics are better than that, but this just isn't your field of knowledge so you'd have no reason to know all this stuff. It happens to be mine. There aren't many of us, but we do manage to get about 500 at the major automotive lighting technical conferences.
All of which means there are enormous areas of knowledge you have that I don't. If one of those subjects comes up and you give a technical explanation, I hope I will have the wisdom and presence of mind to learn what I'm being taught.
No, not at all. Just that people be aware that what works physically doesn't always necessarily work all the way as well as it needs to for reasons that may not be immediately obvious, is all.
slantsixdan
=..=
Oh, sorry! It's here. The site's a klunker; I'll get a new one after I move across the country and buy a house across the international border from where we're moving. :shock: (it's complicated)
TrailBeast
AKA Mopars4us on Youtube
Naw. I almost never trot-out my affiliations like that. Probably shouldn't have this time, either. But I type over 110 words/minute!
Because the lights and reflectors on every car, including yours, are there for my safety as much as yours. They're interactive safety devices; they are the means by which drivers communicate to other drivers so those other drivers can adjust accordingly. If this were something that affected only you, I wouldn't be so insistent about it, since your choice wouldn't degrade my safety. ("my" means everyone else on the road in your vicinity)
From straight behind, subjectively they may be more conspicuous, but:
1. You and I both agree they're less noticeable off-axis, and that translates directly to a greater likelihood of being hit and knocked out of lane because the guy in the next lane didn't see your brake lights.
2. You're not wrong, in one sense, when you say they're more noticeable. LEDs come to full intensity faster than filament bulbs, especially when there's voltage drop in the circuit to the filament bulbs. The brake lights come on quicker, is what that means, and that's undoubtedly good. BUT, the intensity is nowhere near high enough. I've (formally) tested a fair number of brake lights that have been retrofitted with these kinds of "LED bulbs" you used, and not a single one of them has ever come close to meeting the minimum requirements for the brake light function -- not even the old 1971 standard. Most of them even fail the much dimmer tail light function; central intensity on axis is okeh but angle of distribution isn't even near adequate.
That's all it is. I don't mean to mock, deride, belittle or dismiss you. Most people think of a car's lights as "they work" or "they don't work" if they think about them at all. Most mechanics are better than that, but this just isn't your field of knowledge so you'd have no reason to know all this stuff. It happens to be mine. There aren't many of us, but we do manage to get about 500 at the major automotive lighting technical conferences.
All of which means there are enormous areas of knowledge you have that I don't. If one of those subjects comes up and you give a technical explanation, I hope I will have the wisdom and presence of mind to learn what I'm being taught.
No, not at all. Just that people be aware that what works physically doesn't always necessarily work all the way as well as it needs to for reasons that may not be immediately obvious, is all.
Understood, but I think it's probably best just to leave it off the site unless someone specifically asks for the info.
And if someone does, they will get it along with your explanation as to why it may not be the best thing to do, safety wise if that would be good with you.
PS. Where I live people don't even use thier turn signals and drive right through stop signs at most every intersection you come to, so interactive devices designed to notify the other drivers what they are doing or intend to do are totally ignored here by most. (Sucks)
slantsixdan
=..=
Well, yeah, there is that: the best brake light or turn signal in the world doesn't do a particle of good if people won't frackin' use them!
1968FormulaS340
Well-Known Member
1 post from Dan is more useful than 90% of the posts I make.
His posts are important in threads like this because........ Future people may search for "LED rear lights".
Information from all sides helps in making an informed decision.
His posts are important in threads like this because........ Future people may search for "LED rear lights".
Information from all sides helps in making an informed decision.
TrailBeast
AKA Mopars4us on Youtube
Agreed, very good information some of which never crossed my mind.
And I too believe that all info is better than one side or the other.
One that note, can we finish this conversation to conclusion please.
For my info and other that may get here later on the same train of thought.
I support a 4 person houshold with one income so I don't have a lot of money available for my car but would really like to upgrade my rear lighting to make it more noticable in daytime traffic.
Is there an icandescant replacement bulb I am unaware of that is not too costly and uses the OEM socket and lens but will not put a large drain on the charging circuit (Dim other light or slow my signals down at idle)?
I know 1156 bulbs are brighter than 1157's but other than that anything other than LED's cause a big power drain at idle. (as far as I know anyway).
slantsixdan
=..=
Yup! Number 3496. It's described in this previously-linked post. You can get the required bulbs (which have nice nickel-plate bases that will not corrode and seize in the sockets) from your local Honda dealer. Part number for the single-filament variety (replacing 1141, 1156, 1073, 7508, or P21W) is 34903-SF1-A01. Part number for the dual-filament variety (replacing 1016, 1034, 1157, 2057, 2357, 7528, or P21/5W in brake/tail or park/turn lights) is 34906-SL0-A01. Don't try to buy these bulbs in the aftermarket, and don't let the dealer sell you anything but a genuine Stanley-made Honda bulb; everything but the genuine Honda product is junk. The Honda (Stanley) items are ultrapremium bulbs with very long lifespan, corrosionproof nickelplate base, etc.
No, that's not correct. 1156 is a single-filament, 32-candlepower bulb. 1157 is a two-filament, 32/3-candlepower bulb. 3496 is a two-filament, 43/3.5-candlepower bulb.
If your brake lights are causing a "big" drain at idle, there's something the matter with your alternator. Yes, the early Chrysler charging systems are weak at idle, but not that weak!
TrailBeast
AKA Mopars4us on Youtube
Sorry, it's been awhile since I had to remember bulb numbers, but I know there is a different number than the 1157 that was brighter (but drew more amps too)
Not a big drain in my case but I have seen the headlight on some cars get dimmer with the brakelights on. (Mine is a brand new dual field 65 amp with all new grounds)
I don't run amplifiers or any non stock stuff except a CD/FM stereo
Dangit, now you have me curious Dan.
I'm going to have to go get two of 3496 those bulbs and chk out the difference between them and the LED's as far as amp draw and off axis refraction.
If I end up with amber lights in place of my backups I may never forgive you.
slantsixdan
=..=
You're thinking of 2357. Brighter, but higher current draw and much shorter life. The 3496 is way better.
TrailBeast
AKA Mopars4us on Youtube
The LED's made a nice bright spot, but mostly just in the center of the lenses about 3 inches round.
The 3496 bulbs fill the entire lens area with light due to the design of the lenses and off axis reflection assistance of the internal housing of the light assembly.
The 3496 bulbs that Dan suggested are very much brighter than the original 1157 bulbs by about 140 lumens and draw about an amp less power than the original 1157's. (who woulda thunk?)
End result is brighter brake, tail and turns with less power draw on your electrical reserves.
Also ended up being cheaper by about 12 bucks than the LED's
I'm keeping the 3496 bulbs.
Thanks for all the info and help with bulb selection Dan.
One more thing if you dont mind.
I'm going to make my original backup lights into brake and turns also, by wiring them into the brake/turn circuit only of the outer lights.
(All four on with brakes on, and two at a time for the left and right signals) and only the two outer lights on for tail lights.
Since these backup light sockets are a single pole contact, what bulb should I use in those to match the 3496 bulbs Brake and turn performance?
Also I will of course change both lenses to match the brake, tail, turn lenses.
The 3496 bulbs fill the entire lens area with light due to the design of the lenses and off axis reflection assistance of the internal housing of the light assembly.
The 3496 bulbs that Dan suggested are very much brighter than the original 1157 bulbs by about 140 lumens and draw about an amp less power than the original 1157's. (who woulda thunk?)
End result is brighter brake, tail and turns with less power draw on your electrical reserves.
Also ended up being cheaper by about 12 bucks than the LED's
I'm keeping the 3496 bulbs.
Thanks for all the info and help with bulb selection Dan.
One more thing if you dont mind.
I'm going to make my original backup lights into brake and turns also, by wiring them into the brake/turn circuit only of the outer lights.
(All four on with brakes on, and two at a time for the left and right signals) and only the two outer lights on for tail lights.
Since these backup light sockets are a single pole contact, what bulb should I use in those to match the 3496 bulbs Brake and turn performance?
Also I will of course change both lenses to match the brake, tail, turn lenses.
slantsixdan
=..=
Glad to help out. Photo illustration of this what you found is here.
Can't recommend this unless you are planning on running new, heavier-gauge wire to the brake light switch, from the brake light switch to the turn signal switch, and from the turn signal switch out to the back of the car. Otherwise you are overloading the entire circuit by 100%. You probably won't have a fire, but you will starve the bulbs which will drop their output considerably. Of greater concern, you will significantly slow down their rise time to full intensity.
Better idea: separate the brake and turn functions so you have two brake/tail lights inboard, and two turn/tail lights outboard. Use two pairs of stock outboard lenses. This way you also have four tail lamps, doubling your conspicuity while just driving around at night and in the rain. Use two pairs of 3496 bulbs. You'll have to move the rear retroreflector and reversing light functions whether you do it my way or your way. You can use '62 Valiant (+67 Barracuda + numerous other applications) reversing lights, which mount to the rear valance under the bumper. The rear reflector function can be handled by opening the trunk, finding the vertical "wall" that hides under the lip of the trunk lid (but is visible with the lid closed) and applying red peel-and-stick retroreflective tape such as this.
Get a pair of 3497 bulbs (Honda dealer, p/n 34903-SF1-A01). Pick up a pair of these dual-function converters to operate the single-filament bulbs at two intensities, dim for tail and bright for brake or turn. They are not make/model-specific; the seller puts up a bunch of auctions with different makes and models to appeal to different searchers. Easy 3-wire hookup. These operate the single-filament bulb at a dim intensity when the taillights are on, and shoot full voltage to the filament when you step on the brake (or put on the turn signal, depending on how it's hooked up). The original intent of the module is to operate a single-filament front turn signal as a park/turn; they think this is nifty and cool in Europe because American-type amber parking lights aren't legal there, they have to be white. But the module has no way of knowing whether it's operating a front turn(/park) or a rear brake(/tail). If you are smart you wire up this module to make the brake light (not the turn signal) into the single-filament/dual-function lamp. This is because by operating the filament at the low intensity, it preheats the filament, so the brake light comes up to full intensity much faster at night. Better safety.
-DS (posting live from the Society of Automotive Engineers Lighting Committee meetings...)
TrailBeast
AKA Mopars4us on Youtube
For all the info.
I don't have time at the moment to sort out everything you said right now, but I will.
I have two Tail, brake and turn lenses on the way already.
Appreciate it Dan.
I don't have time at the moment to sort out everything you said right now, but I will.
I have two Tail, brake and turn lenses on the way already.
Appreciate it Dan.
-
