headlights just a bit brighter than their daytime running lights?

[stavy]

Has anyone noticed that their headlights are just a little brighter than their daytime running lights?

[MATR6]

I think the DRLs run at 80%.
I always thought the DRLs were at 100%, but they're not.
Disabled mine anyways.

[greywolf]

A little brighter means noticibly brighter. That is normal. It takes a decent percentage increase to be noticibly brighter.

[stavy]

since when does "a little" brighter mean "noticably"?

I mean a little brighter......thanks

[greywolf]

I mean you didn't need test instruments. You could see the difference.

[stavy]

yes you are right, I didn't need or use test instruments. What I am saying is that from my old car the day time running lights are on and when you turn on the head lights, you really notice that they are on. On my Matrix, the difference my be 5 or 10 percent brighter. It kinda makes you say "what is the point in that? might as well just have the headlights on all the time"

anyway, I think we have beaten this one up enough,

thanks to everyone who responded.

[ksbrace]

Reducing the light output slightly helps the headlights last much longer. Here is some content from the Wikipedia entry on light bulbs:
http://en.wikipedia.org/wiki/Lightbu...and_efficiency

Light output is approximately proportional to V3.4
Life is approximately inversely proportional to V16
This means that 5% reduction in operating voltage will double the life of the bulb, at the expense of reducing its light output by 20%.

Taken to a greater extreme than the example above, if the lights are run at 80% voltage, that would be 1/2 brightness and 35x life extension!
A drop to 1/2 brightness corresponds to a single f-stop in camera exposure, a clearly noticeable but not extreme difference, and this is about what I see when I get in my car at night (I don't turn on my lights, but rather wait a few seconds for the car to switch from DRL to normal headlights). So the short answer is, they run the DRLs at slightly lower voltage and 1/2 brightness so the bulbs don't burn out disturbingly quickly.

[mikes_matrix]

the lights are in series ...not parallel like most lights......when you switch to low beam they are in parallel........

that means they are 50% of the bolbs brightness.........using only 6 volts each when the DRL are in use

100% low beams....12volt each

MIKE

[ksbrace]

Looking more closely, I see that the Toyota Matrix Reference Manual for 2003 says that it reduces the "intensity" of the lights to 80% using "duty control" (complete with a little drawing of a square wave on he DRL controller), which means that they have a switch that cycles on and off very quickly, which effectively lowers the voltage to the lamps. The manual doesn't say exactly what the on/off duty cycle is, but to get 80% of the light the duty cycle would be a little above 90%.
My old Saturn used the trick of putting the headlights in series for the DRL function, but this makes for a much dimmer DRL, since at 6 volts the light output is MUCH lower than half. Those 1/2 voltage DRLs were not usable for night driving, and there was no risk that I would accidentally think I had my headlights on and forget to turn them on. The Matrix DRLs put out much more light than that.

[MatrixXRS]

If you want to maximized the brightness of your headlights but do not want to spend on HID's then you should invest in a heavy duty headlights wire harness .



I have that, also upgraded my lows to 80w and highs to 100w .

[trdbryan]

It's the same on my 99 Tercel, that's just how toyota does their DRL.