Koito Headlamp Voltage Rating ~ electrical gurus please help!

[redzedsled]

Hello all! Purchased a pair of brand new Koito Headlamp Sealed Beams from my Nissan dealer and they are marked on the back 6024LH and rated at 24V 75/55W. My original headlamps are marked 6012 and are rated at 12V 50/40W. Could someone in the know please explain what the difference is and any compatibility issues there may be whatwith the different voltage rating. The microfiche suggests that this new pair is compatible with its former number, part number 26705-89905. Any input would greatly be appreciated.

Edited November 6, 2013 by redzedsled

[redzedsled]

Well it's been at least 2 hours now, so I thought I would respond to my own post. I scoured all Factory Service Manuals from 70-78 Z cars and all FSM's indicate that the correct replacement bulb is in fact the 6012. Apparently the 6014 bulb replaced the 6012 with a rating of 60/50W at some point, but not sure on that one.

Aftermarket bulbs now use the H6024, but all seem to be rated at 12V. I kind of expected an "Ohm's Law" beatdown with this thread, but no one has chimed in as of yet. Getting more confused by the minute...

Edited November 6, 2013 by redzedsled

[SteveJ]

Well, you could go over to Nissan : Datsun ZCar forum :Nissan Z Forum: 240Z to 370Z and look up user h4lights. He will be able to address your questions.

Searching a little bit more, it looks like if the bulbs were designed for a 24VDC circuit, you probably will get little light output on a 12VDC system.

Edited November 6, 2013 by SteveJ

[Jetaway]

Hello all! Purchased a pair of brand new Koito Headlamp Sealed Beams from my Nissan dealer and they are marked on the back 6024LH and rated at 24V 75/55W. My original headlamps are marked 6012 and are rated at 12V 50/40W. Could someone in the know please explain what the difference is and any compatibility issues there may be whatwith the different voltage rating. The microfiche suggests that this new pair is compatible with its former number, part number 26705-89905. Any input would greatly be appreciated.

No real help here redzedsled, but I am curious if you tried the 6024LHs. Plugging them in wouldn't hurt the electrical system, but you shouldn't get much light out of them. I calculated down and dirty 18 to 20 watts, which wouldn't produce much of a glow.

The other thing that puzzles me is the 24V rating. I remember reading four or five years ago that 24V was the 'next thing' for automobiles because of less power loss due to resistant and weight savings because thinner wire can be used for conduits and in motors. Plans were apparently abandoned in mass because 24V is much, much, more likely to arc -- painfully or dangerously or both.

Chris

[Mikes Z car]

Thanks Chris, I had heard about the 24V idea for cars being looked at and then it never materialized.

I wonder if the box was made in anticipation of selling 24 volt headlights? The 6024 bulbs I see on the net are rated for 12 volts. The LH after the 6024 just means low beam high beam I assume.

[AZ-240z]

I just noticed this thread for the first time. I have a pair of "new-in-the-box" Koito bulbs marked 6024LH, as well. But, the important

information is on the boxes. The part number on the boxes is "02260-231KO". Checking this part number on my trusty parts CD shows

this number to be good up to 07/73 for our cars.

Hope this helps.

Dan