Lighting Comparison

[Hilldweller]

More about cross-eyed mounting:

The idea with cross-eyeing "driving" (aux high beam) lamps, especially narrow beam pencil/spot ones, is to adjust the effective composite beam reach and width to match your needs. If you have an intense spot beam and you point it straight ahead, that's great for throwing tons of light straight ahead, which is perfect for long, straight roads and very high speeds. Most of us drive at less-than-supersonic speeds on roads that have curves, so it can be beneficial to trade off some straight-ahead seeing distance to gain some seeing width. Very little cross-eye is needed, but how much is best determined methodically, with trigonometry, not by guessing or random placement. Determine how far ahead of the vehicle you want the beams to cross. This should be decided based on the intended travel speeds, convert miles per hour into feet per second using simple units cancellation (1 mi/1hr = 5280 ft/3600 sec = 1.47 ft/sec, so multiply 1.47 times the MPH travel speed to get feet per second...or just take the lazy way and use one of those online unit converters!). Allow a 3- to 4-second preview, so if you want a 4-second preview and you'll be going 60 mph = 88 feet/second, you need 88 x 4 = 352 feet of beam reach.

OK, so you want the beams to cross at ~350 feet in front of the car. Then all you need is the separation between the two lamps as mounted on the vehicle, and that sets up a right triangle to resolve. Suppose the lamps are 20" apart. That means the Opposite of your right triangle is 10" = 0.833 ft, and the Adjacent of your right triangle is 350 ft. You need to find the angle between the Hypotenuse and the Opposite. This is done by using the formula Tangent = Opposite/Adjacent. So divide 0.833/350 and you get 0.002371428571. Now take the arctangent (inverse tangent) of that, using your own calculator or one like this, and you get 0.1358°. That's how much "toe-in" each driving lamp should have, relative to straight ahead. As I said...not a lot! At a distance of 25 feet from an aiming screen, that's going to move the beam about 2cm from straight-ahead. Difficult to discern that little movement unless you have a really good aiming screen or a visual aimer. It gets easier if you're calculating for slower road speeds.

 

[Ozarker]

Hilldweller,

What models from Pilot would you say are cheap but still a "decent" light for offroad?

If you have dual battery set ups, check out aircraft landing lights on ebay, used, most are 24 volt, you might find one at 12 or 18V and you can figure out a power source. A small one from a Cesna or Piper would be all you need.

 

[Hilldweller]

http://www.candlepowerforums.com/vb...rcraft-landing-lights-ACLs-yes-another-thread

 

[verdesardog]

Here's my truck with 2 no name "driving" lights on the outside that do a decent job of lighting the edges of the road and two eagle eye 100W spots that do a good job of long distance illumination. All 4 of those lights cost less then $200 to install with one relay for each pair and covered switches.

BTW the Eagle eye lights seem comparable to KC's at a much more affordable price.

 

[Big_Geek]

Thanks for the additional cross-eye information. This is actually the way I ended up mounting these. I did a little "guessing" at the cross-over distance, but then used a shake-out run to validate. On a positive note, I am DONE with all of the wiring projects on my vehicle for a bit, so I can finally get back to just enjoying the driving. I'm going to leave the adjustment allen wrenches in the glove box in case the aim of the Hellas needs a bit of fine tuning.

BTW, my wife told me the truck looks "Hella good". Wait until she drives it at night!

 

[SoCalMonty]

I tested the cheapo lights I have this past weekend for a few seconds (had to connect power manually, didn't get the switch wired in).

http://www.amazon.com/Pilot-Performance-Lighting-PL-193C-Driving/dp/B00062YUU8

I also put in 100w bulbs. About $42 shipped/installed for the whole she-bang (lights and bulbs).

It's a lot of light...I definitely wouldn't find myself needing more of a spot than this, as long as I'm not "Jeepspeeding" at 100+mph at night off road (which I don't do anyway). While it's cool to have lights bright enough to blind a bat and blister the skin of animals 100 yards out, it really isn't necessary. You can have more light than you'll ever really need for a couple hundred bucks.

I still find myself teasing myself on Amazon, looking at LED light bars...but I talk myself out of it. I'll probably give in one of these days.