RE: (ET) "42 volt systems"

["Elie, Larry (L.D.)" <lelie ford com>]

Neil, Steve, everyone:  I am very familiar with the 'coming' 42V systems.  
It was WAY oversold here at the automakers for about a decade but is still 
coming.  I say oversold because it was touted as a 'more efficient 
system'.  Well, the wiring harness will be lighter.  That's about it.  It 
really is just a way for some controls people to put in a bigger 
alternator.  Seriously, any magnetic-field delivering device is limited by 
the product of the current and the number of turns of wire.  If you have 
more voltage, you can use less current, but then you use more turns of 
wire.  It is a zero-sum gain to within a fraction of a percent.  That 
said, the wiring harness can be made lighter at a higher voltage, and the 
power electronics are lighter and cheaper.  Yes, it 'enables' electric 
valve train, etc.; but only in that we can now afford the electronics.  
Yes, you can make a cheaper starter-alternator; but if you want to pay for 
the tooling you could before.  Chrysler did it on a !
6V system in the 1930's.  Our alternators are 50-60% efficient because 
they are CHEAP TO MAKE that way.  My bet is our 42V alternators will still 
be 50-60% efficient because they will be CHEAP TO MAKE that way.  We can't 
go much beyond 130A at 14V because the wire is too heavy to bend at 
production levels.  THAT'S why we are upping the voltage.

That said, there will be 42V chargers on the market soon.

Cynically,

Larry Elie


-----Original Message-----
From: Neil Dennis [mailto:wombat RealNS com]
Sent: Thursday, June 06, 2002 5:10 PM
To: Elec-trak
Subject: (ET) "42 volt systems"


Just finished reading an article about the coming "42 volt" automotive
systems - sounded interesting.  Uses 36 volt battery and 12 volt battery
with all kinds of "dream' stuff.  Maybe automotive will catch up with us
and our antiques.  (;-')

wombat