[ausev] No-phantom-load: quick Zilla question

[Brian Lasseter]

n Thu, Jan 1, 2009 at 10:57 AM,  <tomsmail at wtez.net> wrote:
> Regarding the first two of the three 12V inputs to the Zilla hairball, does anyone know WHY the "SLI" input must be on an "always on" circuit?  As I understand it the parameters are placed in eeprom.  If not, then what have been the observed consequences of tying the SLI and KEY inputs to the same "run" circuit?

I was confused by this too... however I can confirm what Ken says
about the current draw being tiny in comparison to other things (like
the car security computer or the car stereo) which draw power all of
the time.  (I have not measured the Zilla power draw yet.)

In fact... I left my car sitting in my garage unplugged for the last
18 days while I was on Christmas vacation just to see what the idle
power draw was with my DC-DC, car stereo, Zilla, and the original car
security computers all doing their "car is off" thing.  I can now see
that my traction pack lost 14% (3.2 kwh) of it's charge sitting around
for that long.  That is an idle loss of about 180wh per day.  This
also explains why my 216wh SLI (12V accessory) battery would die in
one day before I changed my DC-DC converter to be on all of the time.
(Previously my DC-DC was only on when my car was in "run".)

Back to your original question... Why does the Zilla want to be on all
of the time?  From the way I understand it, the Zilla has to "boot up"
when power is connected to it, and that takes 10-20 seconds.  So you
would not be able to apply power to the Zilla and then immediately
start your car in the next instant (by shorting the SLI and KEY inputs
to the Zilla).  You would need a time delay... and since most people
find a time delay while waiting for their car computer to "boot up"
unacceptable... it's easier to just leave it on all of the time.


-- 
TTFN,
Brian "Lasso" Lasseter

"No Sane man will dance."   -Cicero (106-43 B.C.)