Technology gone too far?

[P T]

Everytime I actuate my Forester headlights I hear the 'pop' of a relay
somewhere under the right side dashboard. I question the use of a relay.
Is this technology simply because you can?

Now, I remember when headlights were turned on by pulling out a knob two
clicks. (I also remember a time when Americans would have been outraged
to pay for water, one of the slickest scams every perpetrated on people,
but I digress.) How is the newer system an improvement? Only 2 possible
ways: one, the modern system prevents dead-battery by turning off your
lights, and two, the daytime running-light safety feature.

Everyone suffered from the dead battery syndrome from time to time, but
only really stupid people were afflicted often, so it wasn't a huge
problem. Also, the warning buzzers that began in the 80s or so modified
the system so that you had to be really really stupid to get stung.

As for a safety feature, I wonder if it couldn't be done more simply
without a relay. I remember when daytime running lights were a trick
mostly only used by motorcycles. One wonders if the safety effect will
be lost when all cars have the feature.

At any rate, I think the headlight relay is another unnecessary
sophistication that can break down. I guess I have sufficient affluence
that it will be someone else's problem, as I will trade in 5 years or
less.

Okay, lay on boys, that's my rant, and damned be him who first cries,
"Hold! Enough!"

Old fashioned Pete

 

[mulder]

There are actually multiple relays. The one you hear is inside the car,
but there are others under the hood. The one inside (by the glovebox)
does have to do with the DRL system, it switches the low beam ground
circuit between normal mode(regular switched ground) and DRL mode
(grounded through the DRL dropping resistor for reduced intensity). When
you turn on the headlight switch the relay activates and you hear the
click.
There are also two relays under the hood for the headlight common power,
one for each side, that are activated when you turn the lights on. \
The use of relays in modern cars is not an inherently bad idea, as it
allows for the heavy electrical load to be carried by the relay and not
the switch in the car, which means that the switches and their
associated wiring can be lighter since they don't need to carry all that
current. This actually increases the reliability of the switches,
although Subaru's switched ground system does actually run the headlight
ground current directly through the switch so only the positive side has
the benefit of relays taking the load. If you are electrically inclined,
it is possible to add ground-side relays(yes, more relays) to eliminate
the voltage drop that occurs as a result of this arrangement and make
the lights brighter.
It is true in general that there is far more complexity in electrical
systems now, and while much of it is good, it may be overdone in some
cars and certain areas. Current BMWs and MBs are a prime example of too
much technology causing both reliability problems and techno-overload
for the driver. Subaru is nowhere near as guilty of adding unnecessary
gadgets and circuitry as many other manufacturers.
Personally I'm not afraid of the electronics and electrical stuff in
modern vehicles, but then again I understand it and how to work with it,
the average owner generally doesn't. Unfortunately many old-school
mechanics can't deal with it either.

 

[Bonehenge]

Everytime I actuate my Forester headlights I hear the 'pop' of a relay
somewhere under the right side dashboard. I question the use of a relay.
Is this technology simply because you can?

Now, I remember when headlights were turned on by pulling out a knob two
clicks.

I can remember when that knob actuated a relay. <G>

Many new headlights draw more current than older models. The wiring
to support that current, along with the proper switch contacts
probably wouldn't fit well in a control stalk.

Relays aren't new technology, and are plenty reliable when spec'ed
properly.

Barry

 

[David]

I can remember when that knob actuated a relay. <G>

I'm remembering that too, in 60s cars. Knob, relay, headlight.

 

[Hallraker]

I can remember when that knob actuated a relay. <G>

Many new headlights draw more current than older models. The wiring
to support that current, along with the proper switch contacts
probably wouldn't fit well in a control stalk.

Relays aren't new technology, and are plenty reliable when spec'ed
properly.

I was reading that too, and while I agree on the topic of overteched cars, I
had to pause and ask myself, "Relays?" I'm sure that there are some pretty
high tech relays by now, but the core concept of the relay is definitely old
school.

Also, I haven't priced relays lately - but I'm sure that a relay is cheaper
than a proprietary switch, even if the relay itself was proprietary.

-Matt

 

[T]

It's a good idea to run the power of headlights through a relay and not
through the dash mounted switch.

In fact it's a great idea to retrofit older cars that _don't_ have such
a feature, generally improved lighting is the result.

Google is your friend:

<http://www.danielsternlighting.com/tech/relays/relays.html>


Now, if you want to talk about tech going too far you could have chosen
sooo many other and better examples:

(Not Subaru specific)
Not having a dipstick to check the oil.
Having a big plastic cover over the motor to keep the DIYer from doing
anything.
Having to drop the motor out to get at.... (any number of things).
And so one.


TBerk

 

[Juan Otero]

daytime running daylights saved me 90 dollars on my insurance. The hell with
going back to the 80's

 

[EQ Shaman]

Everytime I actuate my Forester headlights I hear the 'pop' of a relay
somewhere under the right side dashboard. I question the use of a relay.
Is this technology simply because you can?

Now, I remember when headlights were turned on by pulling out a knob two
clicks. (I also remember a time when Americans would have been outraged
to pay for water, one of the slickest scams every perpetrated on people,
but I digress.) How is the newer system an improvement? Only 2 possible
ways: one, the modern system prevents dead-battery by turning off your
lights, and two, the daytime running-light safety feature.

Everyone suffered from the dead battery syndrome from time to time, but
only really stupid people were afflicted often, so it wasn't a huge
problem. Also, the warning buzzers that began in the 80s or so modified
the system so that you had to be really really stupid to get stung.

As for a safety feature, I wonder if it couldn't be done more simply
without a relay. I remember when daytime running lights were a trick
mostly only used by motorcycles. One wonders if the safety effect will
be lost when all cars have the feature.

At any rate, I think the headlight relay is another unnecessary
sophistication that can break down. I guess I have sufficient affluence
that it will be someone else's problem, as I will trade in 5 years or
less.

Okay, lay on boys, that's my rant, and damned be him who first cries,
"Hold! Enough!"

Old fashioned Pete

In many ways it is actually a weight reduction issue as well. If you run
thin wires to a relay that is closer to the headlights and then thicker
gauge wire to the headlights, you can save a few ounces and, more
importantly (for the manufacturer), a few cents on each vehicle you produce
since thin gauge wire is less expensive than thicker gauge wire. Relays are
cheap, I can buy them for under $1.25...so imagine how cheap FHI must be
able to buy them.

I imagine that relays will go away over time by use of FET's or some other
CPU based function.

 

[Rick Courtright]

I imagine that relays will go away over time by use of FET's or some other
CPU based function.

I can see how FETs or the CPU can handle the switching jobs, but can
they take the place of relays for pure current flow?

Rick

 

[EQ Shaman]

I can see how FETs or the CPU can handle the switching jobs, but can
they take the place of relays for pure current flow?

Rick

In theory, certainly. If FET can be used to switch power in a 2500+ Watt
RMS Amplifier, they should be able to handle headlights, door lock, etc....

 

[mikey]

In theory, certainly. If FET can be used to switch power in a 2500+ Watt
RMS Amplifier, they should be able to handle headlights, door lock, etc....

This is from http://www.edn.com/article/CA484489.html
"High-power IGBTs combine the easy drive and
current-sharing characteristics of MOSFETs with 1-µsec
switching times...Devices such as Eupec's FZ600R65KF1
turn on in less than 1 µsec and off in about 6 µsec to
control 1.2 kA at 6 kV; lower voltage devices such as
the company's FZ3600R12KE3 switch 3.6 kA at 1.2 kV."


mikey