Letter regarding Headlights (long)

Typrus · Post by **Typrus** » Fri Jan 12, 2007 6:18 am

I dunno (shrug). I've always seen the standard bulbs burn in half the time in our dimmer-equipped fixtures at home versus dimmer-ready bulbs. However, whos to say that headlights aren't "dimmer" ready for that very purpose.
No, them having a high and a low beam does not make them a dimmer bulb. It makes them a 2-stage bulb.

The longer the wire you run for a given current, the heavier guage it needs to be for clean power transmission as loss-free as possible.

Lets go with the Cibie H4 high-efficiency bulb Mr. Stern listed. 70/65 watt. Thats for one bulb.
Here's one gauge chart... Shiny. lol. I was actually looking for a stereo wiring guide...
http://www.powerstream.com/Wire_Size.htm
According to it, 18 gauge (our factory headlight wiring) is capable of a max of 16 amps transmission in "chassis wiring" which might not actually be car-chassis, I dunno. Didn't look at the fine print if there is any.
So between the 2 bulbs, 140/130 watts. Thats 11.6667~ and 10.83333~ amps. Within the "safe" limit. But this wiring also has a resistance of 0.006385Ohms per foot. It would be fairly safe to venture to say there is 20 feet of wiring past the single relay in our systems, right? 0.1277Ohms is what the resistance of the wiring would be. Doesn't sound like much, butits enough to lose voltage. Why does a higher Ohm rating make it lose voltage? Because the more resistance (Ohms) there is to the travel of the electricity, the more heat is formed inside the cable/wiring. I guess the best why to phrase it is that the more resistance there is, the more "friction" the electrical molecules have to get past. The harder they have to push, the hotter it gets.
Which brings to the next point. If you are pushing 12 amps through a wire that has a safe limit of 18 (by safe meaning it will just be under the temp where it bursts into flame) you are at 2/3 capacity. This creates a "bottleneck" for the electricity trying to make it push through quicker. What happens when you rub your hands together slowly? Nothing. What about quickly? You get heat. So thats another contributor.
So what about 12 gauge wiring? 41 Amps max chassis wiring. 0.001588 Ohms per foot. Thats more or less a quarter the resistance, and 2.28 times the load capacity. Thats already a huge bonus for us. Also, 12 amps out of 41 is just 29% of capacity. So you really aren't pushing the limit at all. In fact, you could stand to see nearly twice the power output before the wiring gets too inefficient.

Think of wiring as a road. Electricity is the cars. If you have 200 cars per minute needing to pass you, whats the best way to do it? If you try to push 200 cars a minute through a single lane road, they will have to be traveling very fast and very close together. Is this a safe condition? Hardly. Now, take that same 200 cars per minute, and pass it through 3 lanes, and what happens? It becomes much easier to slow the cars down a bit and get them further spaced. Is the condition much safer than the narrower road? Yes.
Its a good analogy, just instead of car crashes from a "road" overload, you're talking wiring bundles bursting into flames and destroying the car.
Not to say our cars would do that. The relay and fusing should keep you well within the safe limit, but you'll still see a strong drop in efficiency. How useful is it to put 15 of something in, and only get 12 out?

I don't know the specific voltage drop for our cars. I'll have to figure out on the back of the headlight which plug is which (if anyone knows, please tell me!) so I can test and post the results.

FOUND IT!
http://www.crutchfieldadvisor.com/learn ... chart.html

Thats for powered amplifiers, but the idea is the same. Just that with power amps, the cleanest power is desired, so a guide like this is perfect.

keith · Post by **keith** » Fri Jan 12, 2007 6:00 pm

Dimmers in your house are a unique situation, they use an SCR to control them which is a little harder on the bulb, when its at max output. At any lower setting, he bulbs will last much longer than at the highest setting.

As for the head lights, larger wire will allow the bulbs to burn brighter, they will have more current supplied to them. But how significant will it be? The bulb offers about 2 ohms of resistance when the filament is glowing. Thats about 6 amps of current flow. 6 amps x .12 ohms = .72 volts dropped by the wire. Your larger wire will drop a fourth of that according to your calculations, or about .18 volts. That yields about an extra half volt for the bulb to use. Considering the non linearity of a filament, that is, at its rated voltage, light output increases at a greater rate than the increase in voltage applied, and its life gets considerably shorter, the bulb could be significantly brighter, but not last as long.

waynehoc · Post by **waynehoc** » Sun Jan 14, 2007 8:24 am

Found an interesting site while googling for lighting info http://faqlight.carpassion.info/index.html

waynehoc · Post by **waynehoc** » Thu Jan 18, 2007 11:58 pm

Typrus wrote:

I don't know the specific voltage drop for our cars. I'll have to figure out on the back of the headlight which plug is which (if anyone knows, please tell me!) so I can test and post the results.

Curiosity got the better of me, so I probed my passenger side composite headlights ('87 2WD wagon) tonight. Total voltage drop due to the wiring, relay and switches was 1.52 volts. 0.5 volts on the feed side to the 9004 bulb, and 1.02 volts on the ground side of the bulb. The total high beam voltage drop was over 2 volts. I only tested with the engine off, so battery voltage was a bit over 12 volts; initial voltage would be higher with engine running, but likely voltage drops would be slightly more as well.

Looking at the rear of the 9004 bulb socket, the drivers side connection to either bulb is fed thru a relay from the battery positive. The center connection is to the low beam filament, and the passenger side connection is to the high beam filament.

The high and low beam filaments are switched to ground by means of our headlight hi/low beam selector/dimmer switch setup, accounting for the fact that our headlights are a 'ground-switched system'.

I don't know what my overall system voltage is with the wagon running at speed at approx 2000 rpm or more, but the FSM states 13.5 to 15.1 volts "from idling to 2000 rpm" when testing the alternator.

So, with 1.5 volts dropped in the lighting circuit on low beam (2+ volts on high beam), it would seem that the headlamps would be starved at idle, and I've known that for a long time, based on how they dim when I'm at a light or stop sign, with the engine idling. On high beam and at 2000 rpm, they might be just getting the "100% rated" 12.8 volts as mentioned on the Daniel Stern site.

Here is the table from the Daniel Stern site:

In many cases, the thin factory wires are inadequate even for the stock headlamp equipment. Headlamp bulb light output is severely compromised with decreased voltage. The drop in light output is not linear, it is exponential with the power 3.4. For example, let's consider a 9006 low beam bulb rated 1000 lumens at 12.8 Volts and plug in different voltages:

10.5V : 510 lumens
11.0V : 597 lumens
11.5V : 695 lumens
12.0V : 803 lumens
12.5V : 923 lumens
12.8V : 1000 lumens ←Rated output voltage
13.0V : 1054 lumens
13.5V : 1198 lumens
14.0V : 1356 lumens ←Rated life voltage
14.5V : 1528 lumens

The Europeans take a slightly more realistic with their voltage ratings; they consider output at 13.2v to be "100%". The loss curve is the same, though. When operating voltage drops to 95 percent (12.54v), headlamp bulbs produce only 83 percent of their rated light output. When voltage drops to 90 percent (11.88v), bulb output is only 67 percent of what it should be. And when voltage drops to 85 percent (11.22v), bulb output is a paltry 53 percent of normal! It is much more common than you might think for factory headlamp wiring/switch setups to produce this kind of voltage drop, especially once they're no longer brand new and the connections have accumulated some corrosion and dirt.

Overal, it looks like it would be good idea to reduce the voltage drop as much as possible. I wonder how low one could reduce voltage drop by installing the (Daniel Stern) recommended relay type setup.

waynehoc · Post by **waynehoc** » Sat Jan 20, 2007 8:39 am

Typrus wrote:
Quote:
I don't know the specific voltage drop for our cars. I'll have to figure out on the back of the headlight which plug is which (if anyone knows, please tell me!) so I can test and post the results.

Did some more googling on this, and there is a site here http://www.4crawler.com/4x4/CheapTricks ... ghts.shtml that gives the pinouts you are looking for and has a lot of good info Toyota specific to headlights wiring upgrade. They also have for sale a relatively inexpensive plug and play upgrade wiring harness for our headlights.

Post by **ARCHINSTL** » Sat Jan 20, 2007 9:06 am

On the back of the H6054 Sealed lamp (Viewed from the BACK of the unit):
..................... ____
....................|......|

The vertical left prong is for GROUND;
The horizontal middle top prong is for LOW;
The vertical right prong is for HIGH.

Tom M.

Typrus · Post by **Typrus** » Sat Jan 20, 2007 3:26 pm

84 high-idling. Battery read 14.15Volts throughout test.
Passenger Side- High=12.40V read Low=12.95V read Common=13.10V read
Drivers Side- High=12.62V read Low=13.08V read Common=13.05V read

So, if I am calculating this right....
PH=1.74V drop PL=1.20V drop PC=1.05V drop
DH=1.53V drop DL=1.07V drop DC=1.10V drop

Take the highest from both sides, Pass. circuit= 2.79V drop Drivers circuit=2.63V drop.... Jeeze..

Holy crap. Wow. So to transpose from DS chart, thats a drop from ~1356 Lumens to between 597-695 Lumens.
My wiring stinks >.<
I just don't look forward to having to pull the loom apart to get at the wiring.

Typrus · Post by **Typrus** » Sat Jan 20, 2007 3:30 pm

Unless I switched Common and High.... According to the diagram you guys gave I was right though....

Gasoline Fumes · Post by **Gasoline Fumes** » Sun Jan 21, 2007 3:36 am

Typrus wrote:I just don't look forward to having to pull the loom apart to get at the wiring.

You shouldn't have to. You just need to build a mini harness with two relays. It will connect to one of your factory headlight plugs to pick up the low/high signal. No screwing with the factory wiring (unless your lights don't work at all).

I can make a diagram if you need it.

Gasoline Fumes · Post by **Gasoline Fumes** » Sun Jan 21, 2007 4:11 am

Gasoline Fumes wrote:I can make a diagram if you need it.

I guess I don't really need to make one. Just follow Mr. Stern's with one minor difference.

See how the relay coil terminals (#85 & #86) are grounded on one side and get +12v from the headlamp switch? If the Tercel is a switched-ground setup, that won't work. You will still connect the low and high signals from the switch to the relays, you'll just need to connect the other side of the coils to +12v instead of ground. Either use the same wire as #30, or even better, hook it up to the ignition so you won't drain your battery as quickly if you leave the headlamp switch on (parking lights will still stay on).

waynehoc · Post by **waynehoc** » Thu Feb 08, 2007 11:01 pm

Curiosity got me again... I ordered the wiring harness from 4crawler.com and installed it last night. Was a quick and easy install - most of the time spent was figuring out where to route the harness and where to attach the relays, etc., in the engine compartment.

Tonight, I measured the voltage drops with the 'new' wiring harness setup. I measured both driver's and passenger's sides, but for comparison, here is the passenger side. Low beam, stock wiring, total voltage drop was 1.5 volts; 'new' harness the total voltage drop was only 0.35 volts. High beam, stock wiring, total voltage drop was 2.3 volts; 'new' harness the total voltage drop was only 0.5 volts.

Measurements were all taken with engine off.

So, the gain in voltage to the low beam with the new harness was 1.15 volts on low beam and 1.8 volts on high beam.

Referring to the Stern light output vs voltage table in my earlier post above, it looks to be a worthwhile improvement overall.

Post by **ARCHINSTL** » Fri Feb 09, 2007 1:05 am

Pardon my math if faulty, but does this mean that you are getting an increase in lighting output of about 62% on the low beams and 68% on highs?
I presume this is really noticeable - seems like a quite worthwhile investment.
Tom M.

Iain · Post by **Iain** » Fri Feb 09, 2007 7:12 am

It is, I used to run a PIAA upgrade harness on my 87 Corolla GT-S, I measured similar gains in output. Plus, I ran Osram H4 80/100w bulbs. Passengers in my car would comment that it looked like daylight in front of my car at night on the highway, and that was on low beam! I would then switch to high beam, tripple the distance of the beam! My lighting set up on that car was better than and after market or OEM HID out there. It would overpower the HID beams from BMW on the freeway!!!

Mac · Post by **Mac** » Fri Feb 09, 2007 6:14 pm

my 80/100W lights are like regular H4's i bet there is a ton of resistance in my 20 year old wiring harness.

I want to do HID's, but i might sell the car before that. It also depends on if i can set up an account with a wholesaler, but it seems wholesalers are the most business-unprofessionals out there.

One bonehead actually thought we wen't through the process of paying a lawer to make our corporation and setting up a website for the company just to scam them, I don't think they grasped that a corp is alot more work/money than a $60 business licence.

waynehoc · Post by **waynehoc** » Fri Feb 09, 2007 7:20 pm

Pardon my math if faulty, but does this mean that you are getting an increase in lighting output of about 62% on the low beams and 68% on highs?
I presume this is really noticeable - seems like a quite worthwhile investment.

Well, this is all highly subjective on my part, but they do seem somewhat brighter to me. I just finished checking my charging voltage at 2000 rpm and it is 14.6 volts across the battery terminals. The total voltage drop for the pass side hi and lo beams are virtually the same (with the engine running) as when measured with the engine off.

Bottom line, I am now getting 14+ volts at the headlights, which is the 'rated life voltage' according to the D Stern table.

The other thing I just noticed tonight after a 15km drive home from work, is that the lenses on my ('87 wagon) composite headlights are both warm to the touch. This was not the case before, and I wonder if this is the reason I always noticed a bit of condensation lower down on the inside of the lenses.

To summarize, very approximately, with the factory wiring harness, I would infer that I was getting 14.6V - 1.5V = 13.1 useable volts to the low beams = approx 1075 lumens; now I am getting 14.6V - .4 volts = 14.2 useable volts = approx 1400 lumens. This is a gain of approx 30%.

For high beams I was getting 14.6 - 2.3 = 12.3 useable volts = approx 900 lumens; now I am getting 14.6 - .5 = 14.1 useable volts = approx 1375 lumens. This is a gain of approx 53%.

Definitely a much bigger gain with high beams than with low beams.

A final thought - to get an approx 30% increase in headlight output without any headlight conversion, you can just go out and buy a pair of GE NightHawk bulbs or sealed beams, which will eventually burn out and have to be replaced. The wiring harness upgrade does the same or better, and doesn't 'burn out' ...

An afterthought - the bulbs in my wagon are 9004, not 9006, and rated at 1195 lumens hi beam/690 lumens lo beam, so the numbers above and in the D Stern table would have to be changed proportionally to give the numbers for 9004 bulbs. The % change/increase by installing the wiring harness with relays remains the same.