Replacing old 6v headlight bulb w/modern brighter bulb - Page 2

 
The power is the point.

I used to work on luxury cars, and I presently do work with CAN.

A few points ...

As of several years ago, many vehicles were approaching a 2kW electrical
system (maybe they're already there).  The issue with higher voltage is that
one can use less copper and transmit the same power because the wire sizing
is related to the current rather than the voltage.  The upper limit on the
voltage is:

a)Insulation breakdown.

b)Human safety.

(a) isn't a concern at all with modern insulations.  (b) I think led to the
adoption of 48V as the standard.  It was as high as they could go without
endangering the people who service the vehicles, both professionally and
recreationally.

As far as CAN ...

CAN (and vehicle networks in general have led to two trends).

First, when all the electronics can talk to each other, you can have
features that you couldn't have otherwise, or at least couldn't have without
a lot of extra wire.

Second, the tendency is towards "zonal" electronics.  If the vehicle horn is
closer to the engine controller than the instrument cluster, it makes sense
to wire it to the engine controller.  Driver presses the horn switch, is
sensed by instrument cluster, message is transmitted via CAN to the engine
controller, horn relay is closed, etc.

Some of the older luxury cars are good example.  Due to the complexity of
power windows, there were some wiring harnesses going into doors where there
were about 50 conductors.  CAN can get it down to 4 (power, ground, and two
network wires).  The fact that the power windows are all controllable from
the driver's door can be done via network messages.

 

Holy shit!

Otoh, I can understand that. My BMW has a 750 W alternator to run the
ABS, extra lights, heated vests, and so forth.


You explained it better than I did. Thanks. :-)

--
Timberwoof <me at timberwoof dot com>
faq:  http://www.timberwoof.com/motorcycle/faq.shtml
Ten Steps to Fascism: http://www.guardian.co.uk/usa/story/0,,2064157,00.html

 
The other element of the equation that makes the "zonal" approach attractive
is that microcontroller-based modules (i.e. electronic black boxes) have
really come down in price relative to wire harnesses.  So, if you can do
away with 46 of the wires going into the driver's door and use an electronic
box in the driver's door, this decision only makes sense if that electronic
box is cheap enough.

If the electronic boxes are expensive enough, it is still cheaper to have 50
wires going into the driver's door ...

 

... and it becomes a question of a massively parallel "computer" with
dead-stupid 1-bit switching components and one data line for every bit
(a fancy way of saying old-school wiring harness), or a multi-bit
computer with 1-bit serial i/o and each device with its own i/o device
to talk to the data bus.

--
Timberwoof <me at timberwoof dot com>
faq:  http://www.timberwoof.com/motorcycle/faq.shtml
Ten Steps to Fascism: http://www.guardian.co.uk/usa/story/0,,2064157,00.html

 


Well, 6V and modern bulb don't quite go together but.........
You might do better going to a major auto parts outlet armed with the number
off the original bulb.
They should have a cross-reference book with specs.  Look for something with
the same base but higher cp or lumens.  As long as you stay with 6V, you
shouldn't need to change anything else.

Good luck.  I think you're gonna need it.

PS Might try GE or Sylvania or Chicago Miniature ONLINE for cross-ref
listings.