A few headlight questions:

1. What's the voltage that headlights are rated at (I think it's 12.
2. Is there a chart somewhere that shows expected lifetime vs voltage (more voltage, how much shorter life; less voltage, how much longer life)
3. Similiar chart for light output vs voltage
4. A reasonable upper limit on voltage input to a headlight for max light output (assuming that you isolate the headlights from the rest of the electrical system)

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Ed
64 Valiant 225 / 904 / 42:1 manual steering / 9" drum brakes

Uhhhh.....I think Dan just left for Europe.

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Yeah....Im the one who destroyed this rare, vintage automobile.....

Dig around here until Dan gets back (He won't mind):

http://www.danielsternlighting.com/tech/tech.html

More than you ever wanted to know about automotive lighting.

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"When you find a big kettle of crazy, it's best not to stir it." - Pointy-haired Boss

1964 Valiant V200, 225/Pushbutton 904
BBD, CAI, HEI, LBP, AC, AM/FM/USB, EIEIO

Well, here I am. I just got home from eleven hours in the air back from France, where I was at a headlamp R&D congress (really cool nighttime test drives...LED headlamps are just around the corner, and I got to drive a brand-new €60,000 Citroën C6 with swivelling/autolevelling Xenon projector beams!)...so it will be nice to think about nice, simple glowing-filament ones that stay put for a change.
US automotive lighting devices are all rated at 12.8v, yes.
Output-

Fn = Fr (V'/V)^3.3

Life-

Ln = Lr (V'/V)^-13

where:

Fn = new output
Fr = rated output
Ln = new life
Lr = rated life
V' = new voltage
V = rated voltage

If you don't have Fr or Lr values, you can knock those variables out of the equation and just get a multiplier.
Depends on the type of headlamps you're running, which is a significant question because while you can make any filament lamp brighter or dimmer by varying voltage, this does not have an effect on the quality or focus of the beam itself.

What is your specific goal? You wanna see better, you wanna wring the highest possible intensity out of a particular pair of headlamp beam units, something else?

One of the nice things about owning an old car is that the standard-format headlamp buckets mean you have a fairly wide choice of beam units you can install...

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一期一会
Too many people who were born on third base actually believe they've hit a triple.

Equations, great..


This came from an expansion of the MOSFET idea..... Why not run a boost converter to the lights for more light. (or at least constant output so there's no voltage loss no matter what the rest of the system is doing)


I think upper limit is where the equations breakdown and the lights go 'poof' when you hit a bump. I was thinking the 15-16v range. (or even adjustable)

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Ed
64 Valiant 225 / 904 / 42:1 manual steering / 9" drum brakes

Been done—do a search for "Catz Zeta". Really poor idea. You get headlamp life measured in tens of hours. If better seeing is the goal, it's better to run more powerful bulbs fed losslessly at something somewhere near rated voltage.
Let's run some numbers:

Output % of rated flux, Life x rated hours

10.5V : 51.0%, 13x
11.0V : 59.7%, 7x
11.5V : 69.5%, 4x
12.0V : 80.3%, 2x
12.5V : 92.3% 1.3x
12.8V : 100%, 1x
13.0V : 105.4%, 0.8x
13.5V : 119.8%, 0.5x
14.0V : 135.6%, 0.3x
14.5V : 152.8%, 0.2x
15.0V : 171.5%, 0.1x
16.0V : 213.5%, 0.06x

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一期一会
Too many people who were born on third base actually believe they've hit a triple.

I thought the rated life was at 14volts...........


So you're better off doing the following:

1. Upgrading your wiring first.

then if that's not enough

2. Better bulbs. (why waste good bulbs on crappy wiring )


Thanks, I'll just work on the MOSFET relay idea with better wiring then.....

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Ed
64 Valiant 225 / 904 / 42:1 manual steering / 9" drum brakes

It shouldn't matter what side the relays are on if you protect the circuit with a fuse right??????

I was thinking alternator to right side light, run 3 wires to left side light (power and 2 grounds from right side light) then run the 2 ground wires to relays and from relays to battery ground.


The idea being that the lights get the higher output of the alternator before any other circuits, and both lights would have the same amount of total wire length so they would be identical brightness

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Ed
64 Valiant 225 / 904 / 42:1 manual steering / 9" drum brakes

Some small bulbs (signals and indicators) are life-rated at 14v. And, weirdly enough, dual-filament US-spec bulbs (e.g. the 1157) are output- and life-rated at 12.8 on the major filament, 14.0 on the minor!

Good idea.
Or look at it from the other end: Seems a shame to run good wiring to cruddy headlamps!

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一期一会
Too many people who were born on third base actually believe they've hit a triple.