LED Rear Brake Lights

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If they are telling the truth about using a constant current IC, I like that assuming it is a switcher...using resistors is inherently wasteful, inaccurate, and offends my sensibilities. The power loss is not dramatic, but still...
Maybe they are even using one of the parts I designed a few years ago!
 
It's possible. Going from start of design to being in the production line, that's what, 2 to 5 years?

I think the resistors are not for ballast but rather to fool the (BCM?) into thinking that a valid load is present.

Switchers are pretty cool tech, wished I got to work with them more. Once in a while I dabble with them, but these days the chip is pretty well integrated, at least at the power levels I need. Monolithic caps are getting pretty big and making the design easier, and I think we are past the sourcing issues we had for the last couple of years (design and spec a cap, and it'd be NLA the following day).
 
Originally Posted by supton
It's possible. Going from start of design to being in the production line, that's what, 2 to 5 years?
I think the resistors are not for ballast but rather to fool the (BCM?) into thinking that a valid load is present.
Switchers are pretty cool tech, wished I got to work with them more. Once in a while I dabble with them, but these days the chip is pretty well integrated, at least at the power levels I need. Monolithic caps are getting pretty big and making the design easier, and I think we are past the sourcing issues we had for the last couple of years (design and spec a cap, and it'd be NLA the following day).

Ah, good info!
I assumed they were making a crude current source with the R (heavily dependent on the battery/alternator voltage and the LED forward drops), sounds like that may have been a poor assumption...I'll have to do some homework on the details of these LED modules.
Thanks!

BTW, if these aftermarket units are sourced from China, we're probably talking way less than 2-5 years from concept to production...maybe 2-5 months?
;^)
 
I personally am OK with what I have . The LED's would save a little electricity , but I doubt you would ever realize it at the fuel pump .

LED headlights would save more energy / fuel , I think . Still do not know if you could tell the difference at the pump .

But if that is the way you wish to spend YOUR money , knock yourself out . :)

Wyr
God bless
 
Originally Posted by WyrTwister
I personally am OK with what I have . The LED's would save a little electricity , but I doubt you would ever realize it at the fuel pump .

LED headlights would save more energy / fuel , I think . Still do not know if you could tell the difference at the pump .

But if that is the way you wish to spend YOUR money , knock yourself out . :)

Wyr
God bless

I like LED tailights, they turn on faster and thus might shave precious milliseconds off reaction times. OTOH less heat being made means possibly being coated in snow in bad weather. They certainly can be brighter and sharper.

Originally Posted by Virtus_Probi
BTW, if these aftermarket units are sourced from China, we're probably talking way less than 2-5 years from concept to production...maybe 2-5 months?
;^)

I was thinking more along the lines of your chips, if you were working a for a semi that in turn supplied an OEM (or one of their vendors), then it's a 2 to 5 year wait. China, that's more like 6 months I'm guessing, consumer products are much faster out the door, and wild guess here on these bulbs is that it's not OEM quality level.
wink.gif
 
Yes you wire the resistors in parallel with the LEDs to fool the car's bulb check circuit which measures the current flow. The resistors aren't involved at all in making light. They just sit there and burn extra current so the car doesn't report the low current of LEDs as a bad bulb. This isn't necessary on all cars of course.
 
Originally Posted by mk378
Yes you wire the resistors in parallel with the LEDs to fool the car's bulb check circuit which measures the current flow.


Don't you mean in series? In parallel would reduce the resistance/increase current. I've never used load resistors to wire in LED's so no first hand experience. It's been a long time since I've played with circuits...30 years?!
 
Here is my guess . If the resistance of the total LED circuit ( LED lamp + electronics ) is high , a second resister in parallel , of the proper value , would produce a combined resistance . Which , if done correctly , would be ~ to the resistance of a single , OEM incandescent lamp .

The current draw would be ~ to the OEM incandescent lamp . So the car computer / electronics are happy . But in this case , there would be little , if any , reduction in energy consumption .

Again , this is my guess . I have not done this . I have only installed LED lamps on 120 VAC circuits . And nothing monitors as to if a lamp has quit . Other than the humans occupying that space .

But Ohm's law is still Ohm's law , 12 VDC or 120 VAC .
 
Originally Posted by supton
Originally Posted by WyrTwister
I personally am OK with what I have . The LED's would save a little electricity , but I doubt you would ever realize it at the fuel pump .

LED headlights would save more energy / fuel , I think . Still do not know if you could tell the difference at the pump .

But if that is the way you wish to spend YOUR money , knock yourself out . :)

Wyr
God bless

I like LED tailights, they turn on faster and thus might shave precious milliseconds off reaction times. OTOH less heat being made means possibly being coated in snow in bad weather. They certainly can be brighter and sharper.


In my experience, LED taillamp bulbs are rarely worth bothering with. Major manufacturers don't give a [censored] about your safety. I find it riseable to expect a safety improvement from a no-name Amazon brand.

1) Philips Vision LED installed in place of incandescent bulb: killed the side-marker functionality of the taillamp. So now people are less able to see your car from the side. Second, the LED lit up fine when I turned on all the lights. But, when I had someone hit the brakes, the entire LED bulb shut off. The back of the car went completely dark (save for the CHSML). Neat function! And this is a "5-star" LED with the package saying it's "road legal" and it's all backed by a 12-year warranty. For some reason, brake light bulbs that shut off when you hit the brakes make me think that you won't be around long enough to cash in on the 12-year warranty
wink.gif
.

2) Sylvania LED installed in place of incandescent bulb: killed the side-marker functionality. The LEDs lit up fine with the lights on. But, when I had my helper hit the brakes, the brake light did not get any brighter, which is the expected/correct behavior for this car. So, again, people behind you don't realize that you've hit the brakes. The package says "lifetime warranty" but for some reason, I don't think that you'll have a particularly long lifetime with taillamps that don't work
wink.gif
.

These are products sold by Sylvania and Philips. Who do you think is more likely to be sued for selling crappy products--Sylvania and Philips, or some random factory in China pumping out LEDs that are only sold on Amazon.com? What are we going to do, extradite some poor chap from China for causing people to get rear-ended? The reality is that few people give a crap about whether you live, die, or end up paralyzed for life--not even Sylvania or Philips seem to care
smile.gif
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If we really want to improve our taillamps, there are several things we can do that are guaranteed improvements.

1) Swapping out blackened bulbs for fresh bulbs. The glass on taillamp bulbs turns black over time and reduces light output. Swapping out the bulbs for fresh incandescent bulbs isn't as sexy as buying LEDs, but new incandescent bulbs with clear glass, not black glass, is a guaranteed improvement
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2) Swapping to LED center high mount stop lamps if your car came with an incandescent CHMSL. There are legitimate aftermarket LED CHMSL units made by Hella.

3) Moving your CHMSL to the top of your vehicle. It's more visible and effective when it's higher up on your vehicle and less likely to be blocked from peoples' line-of-sight. No, this isn't as sexy as buying new LEDs, but it's basically a $0 improvement. All you really need is wiring and crimp connectors, and maybe some screws or double-sided tape.

Too many people have the "parts-hanger" or "throw parts at the issue" mentality when it comes to vehicle lighting. No, throwing random LEDs at your headlamps and taillamps isn't likely to solve anything. It's the equivalent of thinking "my car won't start, let's go throw a new battery, starter, MAF, fuses, battery cables, etc. at my car without doing any careful diagnostic work!"

If your car won't start, it would serve you well to sit down and think carefully about why it won't start and doing some careful diagnostic work instead of throwing parts at the issue. It would certainly save you money to sit down and think about what's going on instead of hanging parts.

Same with taillamps--instead of throwing parts at the taillamps, it would serve you well to think about what works and doesn't work. Those Amazon LEDs are a non-starter. They don't throw light back at the reflector; therefore, they are automatically disqualified from consideration in most modern vehicles. Thinking carefully about taillamps could save you money and possibly save your life
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Ah, I don't think I advocated one to change their bulbs--I like OEM solutions for LED's in the taillights.
 
Originally Posted by supton
Ah, I don't think I advocated one to change their bulbs--I like OEM solutions for LED's in the taillights.


A valid distinction, but one often lost on readers or purposely ignored
wink.gif
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My post was meant more as a response to the OP.
 
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I'd be happy if everyone checked now and then for burned out brake light bulbs.
When they stopped safety inspections in my area this problem predictably started cropping up.
 
I replaced all bulbs in my Pacifica (except for the HID headlamps of course) with LEDs and am impressed, they have been working solid for over a year now. I check the bulbs monthly as LED bulbs from China tend to be of dubious quality.

My experience with LED bulbs is that they work best in a housing where the bulb is not blocked by a diffuser or reflector. (basically meaning see-through plastic, lens color does not matter). I've found that in diffused housings the light simply isn't bright enough, and the transition from low intensity to high for brake lights is not as noticeable. For turn signals, most vehicles will require you wire a 6-ohm resistor in parallel so that the current draw is equivalent to a stock incandescent bulb. This negates any power savings but prevents hyper-flashing.

I prefer the ON-OFF LED light as opposed to the incandescent's inherent delay-- both for aesthetics and ability to grab attention.
 
Originally Posted by gathermewool
I purchase my LED's from reputable retailers. I might be over-paying, but I feel like you get what you pay for.

All of my LED's are from Diodedynamics.

RE: blinker rapid-flash fix: DD replaces a module instead of increasing the load on the circuit:

https://www.diodedynamics.com/led-flasher-for-2009-2018-subaru-forester.html


+1 for Diode Dynamics. Love my SL1 LED headlights.

Originally Posted by Deontologist


In my experience, LED taillamp bulbs are rarely worth bothering with. Major manufacturers don't give a [censored] about your safety. I find it riseable to expect a safety improvement from a no-name Amazon brand.

1) Philips Vision LED installed in place of incandescent bulb: killed the side-marker functionality of the taillamp. So now people are less able to see your car from the side. Second, the LED lit up fine when I turned on all the lights. But, when I had someone hit the brakes, the entire LED bulb shut off. The back of the car went completely dark (save for the CHSML). Neat function! And this is a "5-star" LED with the package saying it's "road legal" and it's all backed by a 12-year warranty. For some reason, brake light bulbs that shut off when you hit the brakes make me think that you won't be around long enough to cash in on the 12-year warranty
wink.gif
.

2) Sylvania LED installed in place of incandescent bulb: killed the side-marker functionality. The LEDs lit up fine with the lights on. But, when I had my helper hit the brakes, the brake light did not get any brighter, which is the expected/correct behavior for this car. So, again, people behind you don't realize that you've hit the brakes. The package says "lifetime warranty" but for some reason, I don't think that you'll have a particularly long lifetime with taillamps that don't work
wink.gif
.

These are products sold by Sylvania and Philips. Who do you think is more likely to be sued for selling crappy products--Sylvania and Philips, or some random factory in China pumping out LEDs that are only sold on Amazon.com? What are we going to do, extradite some poor chap from China for causing people to get rear-ended? The reality is that few people give a crap about whether you live, die, or end up paralyzed for life--not even Sylvania or Philips seem to care
smile.gif
.


I've found those Sylvania and Philips LED's are VERY application specific. I had the Sylvania ones in my Durango and they worked but needed a resistor to make them not hyper flash (the ultimate reason I removed them). Filled the brake/turn light perfectly, dim mode was similar to the regular bulb and the turn/brake mode was a little brighter. But the dinky little 194's for the tailgate lamps? Absolutely garbage.

I don't recommend switching to LED if you have to wire in resistors... if you put a resistor in and the LED fails, the car might not know the LED has failed and you won't know you don't have any brake lights unless you check them frequently.
 
Originally Posted by supton
Originally Posted by WyrTwister
I personally am OK with what I have . The LED's would save a little electricity , but I doubt you would ever realize it at the fuel pump .

LED headlights would save more energy / fuel , I think . Still do not know if you could tell the difference at the pump .

But if that is the way you wish to spend YOUR money , knock yourself out . :)

Wyr
God bless

I like LED tailights, they turn on faster and thus might shave precious milliseconds off reaction times. OTOH less heat being made means possibly being coated in snow in bad weather. They certainly can be brighter and sharper.

Originally Posted by Virtus_Probi
BTW, if these aftermarket units are sourced from China, we're probably talking way less than 2-5 years from concept to production...maybe 2-5 months?
;^)

I was thinking more along the lines of your chips, if you were working a for a semi that in turn supplied an OEM (or one of their vendors), then it's a 2 to 5 year wait. China, that's more like 6 months I'm guessing, consumer products are much faster out the door, and wild guess here on these bulbs is that it's not OEM quality level.
wink.gif




Interesting you mentioned the faster light up time....

Very true.

When I installed a led right tail light. . I noticed it came on faster than the old left side. I thought that was very peculiar. Well I got a led just yesterday for my left side .. now they both light up just has fast.
 
Originally Posted by LotI
Originally Posted by mk378
Yes you wire the resistors in parallel with the LEDs to fool the car's bulb check circuit which measures the current flow.


Don't you mean in series? In parallel would reduce the resistance/increase current. I've never used load resistors to wire in LED's so no first hand experience. It's been a long time since I've played with circuits...30 years?!

No, the proper way to wire them is in parallel. You're right that wiring the resistors in parallel would reduce the resistance and increase current. And that's exactly what you need to do to keep the bulb-check light from turning on. Think about it: if you have a burned-out incandescent bulb, how much resistance does it have? How much current is flowing through that circuit? The answers: infinite resistance and zero current. And that's what makes the bulb-check light turn on. An LED bulb has very HIGH resistance and draws a very LOW amount of current, just like a burned-out bulb. (low current = low power consumed = energy efficient) If you want the bulb check light to stay off, you need to decrease the amount of resistance and increase the amount of current in the circuit. The load resistors consume power (more power = more current flowing through the circuit) which keeps the bulb-check light off, but negates at least some (best case scenario) energy savings (negates ALL energy savings in worst case scenario).
 
Originally Posted by supton

Originally Posted by Virtus_Probi
BTW, if these aftermarket units are sourced from China, we're probably talking way less than 2-5 years from concept to production...maybe 2-5 months?
;^)

I was thinking more along the lines of your chips, if you were working a for a semi that in turn supplied an OEM (or one of their vendors), then it's a 2 to 5 year wait. China, that's more like 6 months I'm guessing, consumer products are much faster out the door, and wild guess here on these bulbs is that it's not OEM quality level.
wink.gif


I can see you've dealt with automotive qual in some capacity... ;^)
 
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