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Edit: Scroll down to post 7 for an LED H3 that is virtually a perfect match for the stock halogen!!!
There are a couple of other threads out there on LED retrofits but here are my experiences on my 1983 S.
I upgraded to LED headlight H4 bulbs using Ed Scherer’s cap system some time ago, and have been very happy. However the LED H4s really make the original fog and driving lights look pale and yellow. So I decided to replace the original H3 halogens and the standard driving light bulbs with LED equivalents.
The trick on our cars is to find an H3 LED bulb that is short enough and bright enough. Most bulbs on the market now protrude too far inside the reflector and will hit the internal shield. The max length from mounting plate to tip of bulb seems to be about 32 mm to not interfere with the internal shield, and there is not a lot of space behind the reflector either (though I haven’t measured). Another Rennlist member found this particular bulb, one of the few that seems to fit, and it’s rated at 1000 lumens.
The driving light, on the other hand, uses a standard BA15s bayonet mount. I found the below bulb on Amazon, rated at 900 lumens. And I wanted all bulbs to have a color temp about 6000 K to match the headlights.
So far the h3 bulbs look great, but it's not quite identical to stock. The beam pattern is just slightly different, and it would be nice to have an even brighter bulb (1500-2000 lumens rather than 1000) but this seems to be the best available. I spent hours looking for alternatives and there doesn't seem to be anything better right now. As you can see, the original H3 element is located about 18mm above the plate and is very small, whereas the big LED chip starts at about 13mm above and extends to about 23mm above. That likely explains the difference in beam pattern (the stock beam pattern is on the right and is more horizontally focused). Having said that, the upper cutoff is in the same place with the LED bulbs -- which is really the most important part -- and the lower cutoff is lower than with the halogens, which if anything may improve road lighting near the car. I did not adjust the aiming of the H3 assemblies at all.
I'm still in the middle of changing out my radiator so haven't had a chance to get this on the road yet and will report back after driving.
Here's the bayonet bulb I used to replace the driving light. The bulbs were of surprisingly high quality and came in their own box, very well packaged. I like how there are both a ring of emitters as well as a floodlight lens and emitters facing straight ahead. You can't really tell any particular hot spots once installed, so the one-two punch of emitter directions seems to do a great job. Not bad for twelve bucks! The H3s were only twenty, so for $32 and no tax or shipping on Amazon I think it's a great upgrade!!
Thanks for the post. However, the H3 LED does not look much brighter than stock from your pic with the white card. I have been thinking about the H4 LED and fog conversion.
Steve
They seem to be just about right now: Virtually identical beam pattern and brightness compared to the original H3 halogen, very compact LED chip, and of course temp matching with the LED headlights and driving lights. WOOHOO!!
Here are some pic comparing the new bulb (on the left) with both the Calais LED bulb and, separately, with the original H3 bulb.
These new LED bulbs are rated at 1600 lumens per bulb, much better than the 1000 lumens of the Calais bulb, and even better, you can see that the emitters are much smaller in area and are very very close to matching the location and size of the original halogen bulb's filament. I think that's why these new bulbs match the original beam pattern so well now. I'm set!
EDIT 12/19: I’ve had these for some time now and love them. Definitely an upgrade from the originals in terms of visibility AND maintains the original beam pattern. Matches perfectly with the other LEDs in color, the lights together to oncoming cars look like they are all original, also matches well in terms of relative light output with driving lights and headlights. I wouldn’t change a thing.
New H3 LED bulb on left; old H3 LED bulb on the right New H3 LED bulb on left; original H3 halogen on right Old LED on left versus new LED on the right - very compact
I merely pushed the shield up slightly to clear, since they are longer but for fog or DRLs. they are perfect, plus only 20 bucks Canadian from Amazon.ca
Repositioning the shield will alter the cutoff. Yeah, there are a million LEDs available labelled as H3 but very few will fit much less preserve the beam pattern. Also, most if not all of the “too long”’ bulbs place the LED emitter way too far above the mounting plate and therefore not where the reflector lens was designed to work properly, i.e. about 18 mm above the mount which is where the halogen bulb filament is. So the original pattern will not be preserved at all. Look at the pics with the first LED bulbs compared to stock to see how the pattern changed - and that was without altering the shield. That’s why I’m so excited about these new bulbs - they’re a drop in fit, they’re inexpensive and virtually a perfect replacement for the original halogen!
928sg - afaik nobody has posted about these specific bulbs, but it should be pretty straightforward to measure. It will definitely fit inside the shield properly, the only question is back clearance. You can see the exact dimensions in the pic. You could be the first to try on the later model fogs!! 👍
Those look great, how did you do the ground hookup with the two wire harness?
Hey Moose! Thanks for posting. It was your posts that got me started down this path, and it’s really paid off! On my car there are two wires for each bulb already, hot and ground, so just connected appropriately. The ground originally connected to the metal base of the lens assembly.
Hey Moose! Thanks for posting. It was your posts that got me started down this path, and it’s really paid off! On my car there are two wires for each bulb already, hot and ground, so just connected appropriately. The ground originally connected to the metal base of the lens assembly.
No problem, and thanks for finding an even better bulb
Ah yes, I forgot about the ground connection to the base.
12-25-2018, 09:31 PM
H3 and driving light LED retrofit, 1983 US model
