RE: (ET) charger

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

My GUESS (as I wasn't there...)...

I think they feared that some people would be using the ET on a plug in 
the garage or barn that had 
other 'issues'.  For example, voltage drop due to other loads, or droop 
from a long cord.  The 
scenario would have gone like this...

Joe plugs in the ET at 6:00 in off a 50' extension cord.  Although his 
garage is 115V, the voltage 
at the end of his cord under load is about 100V.  He charges for 2 hours, 
and then... he plugs 
something in on the other leg of the 230V going into the garage.  The 
neutral shifts.  The charge 
rate changes a LOT.  Then he plugs in his saw, same line, it changes 
AGAIN.  Yes, they wanted 
constant (or more likely CONSISTENT) voltage.  They knew the current 
changes would change the 
voltage, but they knew that Joe would be plenty mad when his batteries 
that charged in 5 hours on 
Tuesday didn't charge in 5 hours on Thursday.  The customer is ALWAYS 
right, and Joe now 'knows' he 
needs new batteries before the warranty ends.  I believe battery life (or 
better... charging) was 
what killed the ET.  Dealers replacing things that weren't 'broke' to keep 
their customers happy.  
Next time the dealer sold them a John Deere or Bolens.

Again, that's just a guess; there may be other reasons to use the charger. 
 I work for a big company 
(Ford) and sometimes we use a ridiculously expensive (more likely 
ridiculously cheap...) part just 
because of packaging, availability or some deal cut with a vendor.  Those 
are probably just as likely.

Larry Elie


-----Original Message-----
From: Bob Murcek [mailto:rmurcek geisinger edu]
Sent: Monday, April 28, 2003 5:09 PM
To: elec-trak cosmos phy tufts edu; lelie ford com; nagidog starband net
Subject: RE: (ET) charger


Larry,
The transformer in the charger is ferroresonant for voltage stability, 
right?  What's your take on why GE went to that extra expense?

>>> "Elie, Larry (L.D.)" <lelie ford com> 4/28/2003 10:51:02 AM >>>
Engineering is basically the art of compromise.
 
GE knew that fast charging was a selling point.  The charger they designed 
was OVER 1000W (it varies with how low the batteries are) because most 
people in 1970 had 15 Amp outlets.  The timer is all there is... BUT... 
remember, this is not a constant-current charger.  Nor is it even really 
constant voltage, because the load is a major part of the circuit.  The 
current is the limiting factor with low batteries, but eventually as the 
voltage goes to 42 or 44V, the current going into each battery has 
dropped, and the drain at the 120V outlet has gone down from 1000W.  You 
can check this with a Hall-Effect current meter at the batteries, and at 
your plug.
 
It isn't bad for the application, and very good for a 1970 'cheap fix'.
 
Larry Elie
 
-----Original Message-----
From: Jeremy [mailto:nagidog starband net] 
Sent: Sunday, April 27, 2003 3:28 PM
To: elec trak yahoo group
Subject: (ET) charger


I finally got my e-12 in working order and just mowed about an acre of 
hilly, very bumpy ground.  It did great, really a tough machine.  I have 
noticed that the charger really sucks the juice, about a 1000 watts when 
charging.  This seems great if you just want a quick charge and get back 
to mowing, but must be very hard on the batteries and is too much of a 
load for my solar system. . . I can do it, but would bring down my 
available solar power 20% for just one hour of charging.  Spread over time 
the load is not to big for my solar.  I think a DC to DC converter putting 
out 200 or 300 watts would charge more efficiently and put less strain on 
my solar system.  Also, my charging switch-dial has letters from a to G on 
it, but I have not noticed a difference in amperage depending on where the 
dial is set.  Is this dial strictly a timer.  What is the preferred method 
of charging using the onboard charger.  Short spurts over time, one big 
long charge.  Basically looking for the !
 low down on charging technique.
 
Jeremy