What’s a headlight amplifier?
Some years back there was an outfit selling a box called something like that, which was basically just a step-up transformer feeding ~15 volts to the headlamps. With filament bulbs (plain or halogen), output changes exponentially to about the power 3.4 with voltage change, so if you take a bulb rated 1,000 lumens at 12.8 volts and feed it 15 volts, you'll get 1,715 lumens out of it at 15 volts. But lifespan changes exponentially to the power -13 (
negative 13), so if that bulb is rated 500 hours at 12.8 volts, you'll get sixty-four whole, entire hours out of it at 15 volts. Oh yeah, that was the other thing: the chuckleheads selling this "amplifier" also sold expensive, fraudulent headlight bulbs. Gee…!
This is why you want to stay within slapping distance of rated voltage. By all means put in relays to eliminate voltage drop in the headlamp circuit; you'll see significantly better with 'em fed at 13.5 volts than at 11 volts, but try to push it beyond line voltage with an "amplifier" and you'd better own stock in a bulb company.
(Fraudulent headlight bulbs? Yeah, any halogen bulb claiming to produce "extra white" light (or super white, hyper white, platinum white, metal white, xenon white, high "kelvin rating", etc) as its main promotional benefit is best avoided. It doesn't matter whose name is on the bulb—Sylvania SilverStar/Ultra or ZxE, Philips BlueVision or CrystalVision, Wagner TruView, anything from PIAA or Hoen,, Nokya, Polarg, etc—all the same scam. They have blue- or purple-tinted glass, which changes the light color a little, but blocks light that would reach the road if the glass weren't tinted, so they put
less light on the road than ordinary bulbs, not more as the ads claim. To get legal-minimum levels of light through the blue glass, the filament has to be driven very hard so these bulbs have a very short lifespan, and there's nothing about the tinted light that improves your ability to see; the opposite is true (less light = less seeing, no matter about the tint). Sylvania got spanked to the tune of thirty million(!) dollars for false and misleading "upgrade" claims for Silver Star bulbs (see
here)—and those are among the least-bad of an overall bad product category, so the math kind of does itself.)
