Thanks. That's everything I need to
know. If I can't find a decent 6.5V
supply I'll get a lead acid accumulator.
I bought one some time ago for another
application and its been working very
well for more than a year. I can charge
it in the other device. I'd forgotten
about this.
Don
Cory Papenfuss wrote:
For the guy who suggested the lead-acid, it would probably work
pretty well. I measured the current my -DS took under differen loading
conditions awhile back. The flash charging took the most (about 1.5A
peak), the AF motor took about 0.75A, and the rest of the system was
generally below 0.15A... even with the LCD screen on, etc. I seem to
recall that the camera considered 6.5V in "full." By the time it was
down to 6.0V, it was "half." By 5.5V or so, it shut down.
If you look at the discharge curve here:
http://www.homepower.com/files/battvoltandsoc.pdf
you'll see that a floating lead-acid 12V battery is 12.6V at 100%
state-of-charge (SOC). Halve everything, and that's 6.3V at 100% for a
6V battery. A sealed lead acid battery that's about the same volume as
the camera itself is probably about a 5Ah battery, so with camera loads
of <0.5A, it's C/10 or less. At that rate, the camera will think it's
dead about the time it actually is dead... should be fine.
I'd probably want to rig a fuse on it, too... in case you bump the
connector. If the camera faults, it's probably toast anyway.
YMMV,
-Cory
--
*************************************************************************
* Cory Papenfuss *
* Electrical Engineering candidate Ph.D. graduate student *
* Virginia Polytechnic Institute and State University *
*************************************************************************
--
Dr E D F Williams
_______________________________
http://personal.inet.fi/cool/don.williams
See feature: The Cement Company from Hell
Updated: Photomicro Link -- 18 05 2005
