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Replacing incandescent bulbs with cool LED alternatives?

Discussion in 'Roadster' started by S-2000 Roadster, Jul 28, 2011.

  1. S-2000 Roadster

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    Has anyone seen replacement LED lights that will fit in a standard, incandescent auto bulb socket?

    Both the trunk light and the interior light get extremely hot to the touch. I realize that this probably isn't really that significant compared to the capacity of the ESS, but I still have the urge to replace these bulbs with white LED circuits that would remain cool. I could certainly design something like this, either with a custom PCB or maybe even just hand-wiring something, but I have a hunch that there is probably something on the market already.
     
  2. doug

    doug Administrator / Head Moderator

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    In years past I've bought automotive LEDs (for plug and play replacement) from these folks: LED Lights Accessories - SUPER BRIGHT LEDS

    See also Scott's homebrew solution here: Trunk light LED upgrade
     
  3. NigelM

    NigelM Recovering Member

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    I've used them for bulbs for my boat - worth taking a look at the 12v bulbs in the marine section, there may be something the right shape in there.
     
  4. TEG

    TEG TMC Moderator

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    I swapped out most of the incan bulbs on my cars with LEDs too.
    I have had good luck just going on ebay and buying from Hong Kong based suppliers.
    Try this:
    Auto SMD | eBay
     
  5. TEG

    TEG TMC Moderator

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    By the way, be careful about turn signal indicator bulbs. On many cars, the flasher mechanism expects a certain current draw, and the lower powered LED bulbs may cause it to go into "fast flash mode" which is supposed to let you know that one of the "bulbs" may be burned out. Some LED providers offer a ballast resistor to fool the flasher, but then it somewhat defeats the point as you are using the same power as the incandescent bulb. In some cases you can swap out the flasher relay with one designed to expect LEDs.
     
  6. shark2k

    shark2k Member

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  7. roblab

    roblab Active Member

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    Darell Dickey, EVnut.com wires his own LEDs and replaces all his interior lights. He has picture and print information at

    Rav Modifications
     
  8. S-2000 Roadster

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  9. vfx

    vfx Well-Known Member

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    Let us know how it works.
     
  10. S-2000 Roadster

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    #10 S-2000 Roadster, Aug 13, 2011
    Last edited: Aug 13, 2011
    I will, as soon as the shipments arrive.

    For the interior lamp, the LED replacement specifications are slightly larger than the actual bulb, at least in height (not diameter). I'll have to see whether it fits in the fixture without any clearance problems. Sometimes these dimensions are maximums, not actual, so I have a hunch the actual part will fit just fine.

    Meanwhile, the truck/boot lamp measures 37.15 mm, but that does not match any of the parts from the Super Bright LEDs site. I've ordered the 36 mm festoon, 3610-x4, since its seems that the solder on the ends might be responsible for measuring larger. The strange thing is that it's difficult to get an idea of the 'standard' lengths that should be available. JKL Components has a festoon that is 43 mm max, where Super Bright LEDs has 42 mm and 44 mm lengths. Maybe it's just the difference between nominal length and maximum length. I'll report on the fit of the 36 mm festoon, or perhaps someone else here has already replaced their truck/boot lamp and can say which LED part they used.

    EDIT: Looks like the Super Bright LEDs site does have a 37 mm festoon, the 3710-xHP3. They're $7.95 (7 times brighter) or $14.95 (13 times brighter), which seems expensive compared to the $2.84 3610-x4, but I guess you pay for the brightness. I'll have to make a second order with one of these brighter models just to see whether it's necessary.

    Next, I'm planning on looking at the parking lamps and license plate illumination to see whether those are incandescent or LED. The license plate illumination is actually responsible for creating glare in the backup camera lens, so I am hoping that a different lamp will work around that problem. Another option is to fabricate a shield for the camera that prevents the license plate illumination (which comes on when the parking lights are on) from ruining the image. The backup lights themselves are fine, because they are aimed straight back and do not cause lens glare, but the license plate illumination is seriously problematic.
     
  11. S-2000 Roadster

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    I just received the shipment from SuperBrightLEDs, but it will be Monday before the parts from Mouser arrive. What follows is my report so far.


    INTERIOR "DOME" LIGHT: (turns on when you open the doors or manually switch it to On)

    This light has a holder with a twist lock. Standard wedge base bulbs plug straight into the holder and then the holder is twisted into the fixture. The fixture itself can be disassembled, but that's only for the very brave and adept.

    So far, my recommendation is the $4.95 WLED-WHP. Its 120° beam covers just as much area as the original incandescent. I would have preferred natural white, but the only available white is "cool white." It puts out a healthy 15 candles (15000 mcd) of brightness, which is at least as bright as the original. I noticed that the original 5 W incandescent is too hot to touch after it's been on long enough for you to remove the socket, but this replacement is only 0.3 W - quite a bit less wasted energy (94% less waste!). Note that both times I installed it, I got the polarity backwards, and it did not light up. If that happens to you, then quickly remove the base, rotate 180° and reinstall. I cannot remember whether this LED is protected against reverse polarity power, but it did not burn out after two brief instances of reverse voltage. Thankfully, you don't even have to unplug and replug the wedge base bulb itself, because the twist lock holder fits two ways.

    I tried the $3.94 WLED-NW5, which is supposed to have a 220° beam, but it just barely did not fit into the fixture using the normal procedure for replacing the bulb. It's theoretically possible to fit it in there by disassembling the fixture further (see below) and plugging in the bulb after the holder has been twisted in, but I did not bother since the brightness is only 2 candles and I don't think that the wider beam would be of any use.

    I disassembled the fixture with the hopes of fitting in the $11.95 WLEDB-CWHP4-DAC, but ran into a couple of problems. First of all, the killer is that the ring into which the four LEDs are mounted is literally too big in diameter to fit behind the bezel. A second problem is that I would not recommend disassembling the fixture for most people. It takes a rather delicate hand to take this thing apart without breaking it, and the real challenge is getting the it back together. You can see why I did not go back and try to fit the 2-cd bulb.


    TRUNK LIGHT

    The standard festoon bulb that comes stock is 37 mm, so the best replacements will be 37 mm, too.

    Here I recommend the $14.95 3710-CWHP6. It's the brightest they offer, at 66 lumens, and the over-sized package actually fits just fine. Here, you drop from 5 W to 1.632 W, an energy savings of 67%. Again, the original bulb gets very hot and that really seems like a waste to me. Some of you who actually like the warm color of incandescent bulbs might prefer the 3710-WWHP6. Unfortunately, you still have the original problem that if one piece of luggage covers the tiny light you can't see the rest of the trunk. For me, the convenience of replacement far outweighed the potential advantage of installing something completely different. Besides, every trunk has a single light that can easily be obscured.

    I also tried the $7.95 3710-CWHP3 and it seemed fine. It's half as bright as the HP6, but still plenty bright compared to the original. Power is about 0.6 W, or 87% less than incandescent. Also available in warm white as 3710-WWHP3.

    I tried a couple of the 3610-xW4 bulbs, but here you have a slight problem. After removing a 37 mm bulb from the socket, these 36 mm bulbs fit loosely and flicker on and off. They're also rather dim for the trunk at only 5 lumens (4 lumens for warm white).


    LICENSE PLATE ILLUMINATION

    There are two bulbs and holders here, with the same 37 mm festoon bulb.

    All of the same LED bulbs fit, but I notice that they're all much brighter than the OEM incandescent bulbs. Since I have an ongoing problem with the license plate lights causing glare in my backup camera lens, I chose the dimmest LEDs available. I wouldn't call it lens flare - what actually happens is that the light coming in at a 90° angle from above just makes the cheap plastic lens look fogged. With all the fogging in the headlights, I assumed for a while that the backup camera lens was fogged on the inside, too, but it turned out to be the license plate lights.

    It's possible to fit the 3610-xW4 festoon bulbs into the license plate light holders by squeezing the metal springs slightly closed before fitting the new bulbs. You only need to make them 1 mm smaller, which is not too difficult. So far, I don't think that my license plate lights are flickering due to the undersized bulbs, but that may not last. I hesitate to recommend this option since they're technically not to spec. Anyway, once installed, but before screwing on the plastic lens covers, I rotated the directional LED while looking through my rear window at the Alpine in backup camera mode, until the lens looked completely clear. This reduced the brightness quite a bit, but considering that the LEDs are already ridiculously brighter than the incandescent bulbs I think it ended up about the same. On the side opposite the backup camera, I just aimed the LED straight out for full brightness.

    These bulbs are only $2.84, so I guess I'm not too picky that they aren't perfect matches.
     
  12. SByer

    SByer '08 #383

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    On the interior dome light, how is it handling the fade-out dimming when the light goes off? Many LED packages don't deal with dimming circuits well, and I'd worry about that.
     
  13. S-2000 Roadster

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    #13 S-2000 Roadster, Aug 28, 2011
    Last edited: Aug 28, 2011
    Wow, I don't think the Roadster 2.5 has fade-out dimming. But I'm willing to put the original bulb back in there to compare.

    I assume your 2008 must be a Roadster 1.5, so maybe you can tell me how many minutes it takes for the dome light to begin it's fade out (does it start immediately?) and how long the fade itself takes. Also, does this have anything to do with whether the key is on and/or the charge port door is open? Since I've never caught mine dimming the dome light, maybe I can make sure I stick around long enough for the process to start and finish.

    The WLED-WHP is spec'd to operate with anything from 9 VDC to 14.5 VDC, and I suppose it just shuts off below 9 V. If my Roadster 2.5 actually has this dimming feature then I can test whether the LED replacement dims or just maintains until it completely shuts off.

    NOTE: I believe that the "trouble with dimming" should be isolated to 120 VAC light circuits where the sine wave is chopped up with an SCR to achieve dimming. There are certainly LED power supplies that expect a 120 VAC sine wave and really start buzzing or hyperventilating (not literally) when square wave edges come through at up to 120 V peak-to-peak. On the Roadsters that dim the dome light, my first assumption is that the nominal 12 VDC supply is slowly lowered, and that should not pose anywhere near the same problem as you've heard about with 120 VAC incandescent replacements.
     
  14. doug

    doug Administrator / Head Moderator

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    They're not just using some pulse width modulation for that?
     
  15. S-2000 Roadster

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    For 120 VAC systems, you can't reduce the voltage without dissipating a significant amount of wattage and therefore heat, so there the 120 VAC sine wave is chopped with an SCR that allows either the full sine voltage (which varies) or 0.
    For 12 VDC systems, reducing the voltage is probably a cheaper circuit, especially assuming incandescent lamps. If you were to implement PWM for 12 VDC, you'd need a circuit to boost a CPU pin to 12 VDC with 5 W power capabilities, and that's not a cheap circuit. It's possible without a CPU, but the circuit is more elaborate than a simple DC voltage fade.

    That said, I don't know what Tesla Motors is doing. Alas, I think the Roadster 2.5 doesn't have the dimming feature anyway (that I've noticed), so I can't just hook up a 'scope and see what's happening. Anyone have word on whether all Roadster have the same dimming feature (and I just missed it), or is this just a Roadster 1.5 feature?
     
  16. Doug_G

    Doug_G Lead Moderator

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    I doubt they would adjust the voltage, because that presents a heat dissipation problem with the driver transistor. More likely they pulse-width-modulate (PWM) the 12VDC. That's much more efficient, simpler, and cheaper.

    I don't think my 2.0 fades. If it does I've certainly never noticed.
     
  17. SByer

    SByer '08 #383

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    Yes, a 1.5. When I close the door and lock the car, it's about a 1~1.5 second fade, starts close to immediately (as soon as the beep is done?). I'll pay attention a bit more as to the circumstances (I think I would notice the lack of fade, but human memory and perception and all...). I notice it because it seems enough slower than just normal incandescent fade-out to not be accidental.

    I'm aware of fading issues with 120v circuits - and the varying qualities of LED drivers in handling it (a couple of non-dimming circuits are now hosting the 'failures'). Not familiar enough with what 12v circuits would use, thus the question. Certainly intriguing enough to send for the bulb and try it out...
     
  18. Doug_G

    Doug_G Lead Moderator

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    Well, okay, I made a point of looking at it this evening. It didn't exactly clear it up in my mind. It faded out in less than a second; perhaps half a second. That seems a little long for the filament to simply be cooling down, but why would they bother fading it that quickly???
     
  19. doug

    doug Administrator / Head Moderator

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    Agreed. For what it's worth, I happened to use a portable scope on the instrument illumination of my '94 Miata some years ago and even that was pulse width modulated.
     
  20. S-2000 Roadster

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    I just received the $1.28 JKL Components LE-0503-03W on Monday, and finally tried it out. Unless you inspect closely, it looks almost exactly like an incandescent bulb until you plug it in.

    It uses 60% as much current but is not nearly as bright at 0.70 lumens as the $4.95 Super Brights LED product at 15 cd. This being my first attempt to convert candles to lumens, I believe that 15 cd is equivalent to 62.83 lumens, assuming the 120° beam angle of the 15 cd product is accurate. It doesn't appear to be 90 times brighter, but perhaps the dome bezel is limiting that 120° beam.

    Those of you who want plenty of light should try the Super Bright LED, but the cool white color might seem unnatural.
    If you prefer a more subtle light that still fills the cabin and provides plenty of light, the cheaper JKL Components part will certainly suffice. It has the same color temperature, but that seems to be less of an issue when the brightness is of such a lower intensity.

    By the way, I did finally notice the very quick fade, and I didn't even have to restore the incandescent bulb (which I'm thankful of, since that thing gets too hot to touch almost instantly) for comparison. Both of these LED bulbs exhibit that quick ~1 second fade. I'm now curious whether the filament in the incandescent would make the fade appear slightly longer, but not curious enough to keep swapping bulbs. In any event, turning the bulb on and off with the rocker switch is verifiably instantaneous, so the fade is clearly something purposeful.
     

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