280Z LED Conversion Part 1

My 280Z isn’t what you could call “modern” in the electrical department. Originally, it came with an externally regulated alternator, fusible links, incandescent bulbs, and very few relays. The design inhereted a few things from Lucas eletronics, which is not a good thing. Regardless, it was fairly normal for the time. I’m glad there are no vacuum operated things, like some makes. The most electrically obtuse part of the design is the lack of relays. So, all the current for the headlights, parking lights, turn signals, and brakes goes through the individual switches for each. So, not only is there a significant voltage drop by the time the bulbs actually see any current, the switches are very prone to corrosion and failure. Sourcing a replacement column switch is getting harder and harder.

Solutions to this problem? Add in new relays for the lights to significantly reduce the load on the switches, and/or add LED lights to reduce the current draw of the lighting system altogether.

I’m opting to do the latter for now. The power savings are calculated as:

1977 280Z

  • 2 50W/40W headlights
  • 4 Type 97 (1156) 8W bulb side markers (2 amber, 2 red)
  • 2 Type 89 7.5W license plate bulbs
  • 2 Type 1157 23W/8W Stop/Tail lights
  • 2 Type 1157 23W/8W Front Park/Turn signal lights
  • 2 Type 67 8W Rear tail lights
  • 2 Type 1156 23W Rear turn signal lights
  • 2 Type 1156 23W Reverse lights

Incandescent bulbs:

  • 1156 – 23W * 4 = 92W
  • 1157 – 31W * 4 = 124W
  • 67 – 8W * 2 = 16W
  • 89 – 7.5W * 2 = 15W
  • 97 – 8W * 4 = 32W

279W total (not including headlamps). Granted, that’s with the brake lights depressed, in reverse, with the lights and hazards on. A more typical wattage would be 95W.

LED Bulbs

Sidemarkers:

  • 97 (9 LED 67-x9 Amber) – 0.5W * 2 = 1W
  • 97 (9 LED 67-x9 Red) – 0.5W * 2 = 1W
  • 89 (15 LED 67-x15 Red) – 0.5W * 2 = 1W
  • 1156 (45 LED 1156-x45-T Red) 0.14W * 4 = 0.56W
  • 1156 (45 LED 1156-x45-T Amber) 0.16W * 2 = 0.32W
  • 1156 (45 LED 1156-x45-T White) 0.16W * 2 = 0.32W
  • 1157 (45 LED 1157-x45-T Red) 0.165W * 2 = 0.33W
  • 1157 (45 LED 1157-x45-T Amber) 0.195W * 2 = 0.39W

4.92 Watts, and that’s at full load. That’s two orders of magnitude less. Again, that’s with everything on at once. A realistic value is 4.16W. Not a big difference than all of them on, mostly due to the clearance and license plate LEDs taking most of the power in the first place. So, all the parking and operating lamps on the car illuminated for about half the power of a single incandescent clearance lamp. That’s a huge improvement:

4.92 W / 279W = 1.76% of the power with everything on, 4% with just the parking lights.

The catch? LEDs are expensive. Most of the cost is with the 1156 and 1157 replacements, at $20-30 per bulb. Also, digital flasher units are required rather than the heated element type in use (this also has a significant power drop, not calculated here). The total comes out to around $250. Ouch. Cheaper LEDs can be had, but they will not be as bright, and won’t last as long as quality units.

Continued here.

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