Good, old fashioned, head light data

stouchton

stouchton

Senior Member
Well, not old fashioned exactly.....

Decided to upgrade my head lights, and compared perception to actual measurement in lux.

Head lights were refocused between changes.

I measured 4 feet from headlamp, and hunted around for maximum intensity.

For starters, my 67 Camaro's low beams measured 3300 lux. They are GEH6024 halogen bulbs, very bright, never need to use high beams.

So here we go with the Model A data!!!

For starters, my silver plated shiny original reflectors scored 500 Lux with a 32 CP bulb. :(

Changing to Bratton's aluminized reflector scored the 32CP bulb up to 1500 Lux. :) So much for me thinking I did a good silver plating job. :rolleyes:

As a side note, the new Bratton reflectors focused just fine.

50 CP bulb in the Bratton reflector scored 2000 lux.

35W Halogen bulb scored 2000 lux also.

Now, for visual perception the 35w halogen just looks brighter. Hard to explain, seems like a sharper, crisper light. In fact, you can't look at the headlight - it hurts.

Disclaimer details.... engine was not running, battery voltage was about 5.95 (as measured feeding headlight circuit). Lux values are for comparison only. Meter does bare a current calibration certification. Meter uses a "human eye" filter.
 
That's great! Thanks!

First real "data" I've seen.

I plan to try a set of the new Bratton's reflectors here shortly with 32/50 bulbs. You give me hope.

The halogen bulbs are a slightly higher color temperature than regular tungsten bulbs, so your eye sees them as brighter for the same watts.

:cool:
 
Yes nice job. I would not worry about the absolute number of your non calibrated meter gave you but rather the difference between the different components.
 
When I took out the 50cp bulbs and put in the 35watt quartz halogen bulbs the first thing I noticed is that there was not change in light between idle (no + charging) and driving (generator charging) ---the second was that I could reduce the charging rate with the halogen bulbs as compared to the 50cp bulbs.

Since you have a working meter how about doing the same test at 50 feet ----another of the big changes I found with the 35 watt halogen bulbs was that reflectors lit up much further down the road. --about .3 mile
 
Hi stouchton,

Great information -- and thanks.

Light meters are wonderful devices to measure what one can see at different distances with different types of light fixtures & bulbs.

Similar to Kurt's request in response #4, LUX metric readings at about 100 feet, (about 6 car lengths) would be helpful to see how well the highway is illuminated 100 feet out front with different reflectors & bulbs.

It may appear confusing; however:

A. With the metric system, one (1) LUX indicates the amount of lumens detected per square meter of a surface.

B. Then, with the English system, one (1) lumen indicates one (1) foot candle falling on one (1) square foot of area.

C. Again with the English system, one foot candle indicates the amount of light one (1) candle produces one (1) foot away from one (1) candle.

D. One candle power, (CP) or one (1) Candela = 12.57 lumens.

If Bill's Buster-T reads this message, he could add a reply & enlighten all of us & maybe explain it far better in more Hi-Tech scientific terms such as something like:

1. Place a cat in the middle of the road at 100 feet away.

2. Change different reflectors & light bulbs from 32 CP to 50 CP etc., plus halogens.

3. For the best illumination combination, choose which ever bulb/reflector allows one to see the cat more distinctly at 100 feet away.

What a smart dog!
 
As mentioned above, I noticed that the 35 watt halogen bulbs didn't dim at idle like the 50 candle power bulbs. I run 12 volt with the original generator with maximum charge rate at 8-10 amps. I had to run the generator with the third brush all the way down with 6 volt 50 candle power bulbs on six volt and the lights were very dim at idle. The 35 watt halogen bulbs are bright but I can't focus them because the aluminized reflectors that I bought a few years back won't allow them to focus.
 
I too had to crank the 3rd brush all the way to get the 50cp bulbs bright enough---the generator survived many night drives at 18 amps ---with the cover band off for cooling ---I always worried it would loose the rest of it's smoke, the bad optional fuse let some out on the first drive. ---the halogen bulbs have been trouble free for about 15 years so far
 
Glad the data was useful. I can definitely repeat at a further distance - stayed close because I could not back the Camaro out of the garage - my son was asleep in the room right above the car. 10X the horsies is 10X as loud :)

I did shine the Model A lights into the woods about 100 feet away. Halogens did let me see more details in the trees than the 32/50CP.

Though, I was really impressed with the 32/50CP when combined with Bratton's reflectors. Halogens win, but not sure worth the $54 spent.

I live in a state with some strict lighting requirements for antique vehicles to be driven at night. My goal was to obtain proper head lights to be legal, especially with the days getting shorter. With that in mind, I think the 35W halogens would give the police a little less to complain about.
 
Does anyone have a way to accurately measure the current draw (amps) pulled by each of the various bulb options out there?

It sounds like the 12 volt halogen bulbs draw less than the 32/50 bulbs on high beam, but light up better.

I seldom use the high beams, so I'd be interested in the 32 cp current draw, compared to the halogens.

I don't consider the ammeter on the car's instrument panel to be accurate enough to really tell you what the current draw of a bulb is.
 
Jim/TX/GA said:
Does anyone have a way to accurately measure the current draw (amps) pulled by each of the various bulb options out there?
Click to expand...

This was actually on my list to do tonight or tomorrow. Found some conflicting data on the internet, so figured I would just measure my self.

I'll post back as soon as I have it.
 
Ok - here is what I got. Keep in mind I removed the tail light bulbs, and only did one headlight bulb at a time. Engine was not running, so current would go up as the voltage goes up. I could mathematically correct, but these readings should be close enough for comparison:

35W Halogen 5.25A
50CP 4.30A
32CP 3.50A

These are single bulb amperages.
 
Interesting!

These current draw numbers are about what I would have expected at 12 volts.

I currently have 35W halogens and original silver reflectors that are pretty tarnished. They are OK but not great.

I am going to try the new Bratton's reflectors with the 32/50 bulbs to see if the better reflector material can make up for the lower wattage bulb. I'd like to reduce my total current draw at night and this is one thing I identified to do it.

If I don't like it, I can always put the halogen bulbs back in.

Thanks for the data.
 
You need to Double the current for both headlights. My numbers were for a single headlight. That's probably why it looks like 12v numbers. :)
 
How did you focus the various bulbs. Several years ago we did a similar test going to the halogen bulbs and used a modern headlight testing set up and was able to duplicate the image that is in the owner's manual. when you installed halogen were these the kind that fit the original bulb socket and are adjustable?
 
Yes - they were the halogen bulbs that fit into the original sockets.

The filaments were closer to the bayonets, so I had to loosen the adjusting screws almost all the way to get proper focus.

To focus them I simply observed the pattern shining on a wall - I did one light at a time, covering the other with a rag. I left the aim the same, and simply adjusted the focus.
 
I don't know 'bout all that LUM and photo-meter talk but I used Marco's aiming and adjusting directions and my 77 year old eyes can see where I'm going just fine.Try 'em.
 
I did not have time to make additional measurements this weekend, but I did make good use of the headlights.

Final car show for Pottstown was this past Saturday, and instead of scrambling home prior to sunset, I stayed until dark.

Noticed my headlights were as bright, or even brighter, than several late 50's cars. No lack of light driving home - very easy to see cruising at 35-40mph. It was a very dark night, also.

So - I am very, very pleased with the 35W halogen and the new Bratton reflectors.

I have my generator set for 12A. I converted my tail light to LED, and my ammeter was hovering around "0" on the ride home - might have been an amp or 2 discharge.
 
Sounds good.

12A out of the genny is a lot. I recommend you put in a hidden voltage regulator or you will boil your battery running during the day.
 
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