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Recently morimoto / aftermarket ballasts started having issues. No idea if morimoto ballast is the cause or bulbs got older, but buying x2 new ballasts and possibly 4x new Osram CBI bulbs seemed too expensive so I decided to do a little experiment.
(they would fail to ignite, but eventually would light up when driving / even without cycling the power on and off)
There seems so be different styles of "D2S LEDs":
The "HID LED" plugs into the existing ballast, so it requires functioning ballast to work. This feels weird for me, but hey, I said it's an experiment. Ballast outputs 20-25kV only during startup to strike an arc, but normally they output ~80V AC or so (don't quote me on that, but even OEM ballast says that it outputs 80V. Different sources list different voltages and I have no equipment to measure in kV range. I guess it's possible to make power supply for LED that runs off ~80V AC. I wonder if they would work if I plugged them into the wall outlet lol).
The "12V LED" simply runs on 12 volts and doesn't require ballast. If your ballast / igniter went out and you don't want to replace them this might be a workaround. Those are plugged (with some adapters) into the relay harness that was used for Morimoto ballasts.
All following photos are taken with "proper" camera in manual mode, so ISO, F, shutter time, etc. should be constant. The "left / right" label means that I'm aligning the headlight to left or right hinge to see the output at the edges. All photos are taken on the same headlight housing. If you're confused why there's a "OEM projector" and "Second projector", refer to the elrifas' thread.
Here, LED seems to have a dark spot in the center, but overall more even light distribution and seems to be better at lighting up corners, which was counter intuitive. I was certain that I will have trouble with getting a more evenly light output than HID.
Now the second / Morimoto projector:
The second / Morimoto projector is smaller than OEM so that might be the reason for different beam pattern. I lost nice blue line cutoff and there's a hot spot in the center and there's more light to the ground than the same projector with HID bulb.
I'm not a big fan of center hot spot on the second projector with LED bulb.
Some close ups (previous photos were taken with headlight as far as I have room in the garage) :
Harder to see details when headlight is closer. The second projector 12V led makes a moth-like pattern. And hot spot is slightly below the cutoff line, while same projector with HID bulb has hot spot right in the center and right at the cutoff line.
I don't have the outside before and after pictures. 4x LEDs are brighter than 4x HIDs. There seems to be more glare too, but glare was always there so it might be more noticeable due to increase in brightness.
The OEM and Morimoto ballasts with "HID LED" connected seem to draw around 42W or power, very close to what they would draw with HID bulb. The "12V LED" draws 55W.
The 35W + 35W HID system should output less light than 35W + 55W LED system, considering slightly better efficiency of typical HID vs LED bulb.
The actual feeling on the road confirms that. I might try some other LED bulb in second / Morimoto projector as there's more light in front of the car than I'd like. The corner visibility didn't change, except that it's brighter, but the cutoff line / angle on the sides wasn't impacted by LEDs.
Seems like converting HID -> LED can work. I would advise against doing that before, now I can understand it could work, I'll see for how long...
Right. Now the biggest concern is reliability. OEM ballasts are going strong for 18 years and Morimoto lasted ~5.5 years. Before, both OEM and Morimoto were running with Osram CBI D2S that were bought at the same time. LEDs are more finicky - they require cooling. The "HID LED" is closed inside the housing so there's little air flow. The "12V LED" is sticking outside, so assuming ambient temp is lower and they don't "breathe" hot air from the engine bay, they should have easier life, but they get hotter (42W at the ballast vs 55W right at the bulb). If something fails or I make some changes I might come back to update the thread.
