My first impressions - and some info...

Started Jul 28, 2001 | Discussions thread
OP Wayne DeWitt Senior Member • Posts: 1,259
Re: About batteries...

Jim Popenoe wrote:

Wayne,

Any sleuthing your technician can do would help, and many on the
forum would be grateful if you let us know what you discover.
Battery performance is something I want answers about before I
purchase a Dimage 7.

Some D7 owners on the forum say they are doing just fine with NiMH
and getting over 100 photos per set. Others are running out of
juice in 5 minutes or less.

That person has either a seriously defective camera or a bad cell. I get 1/2 hr.+ of continuous use with a lot of reviewing of photos, autofocus and occasional flash use.

I assume everyone (or most everyone)
is being honest. So why the different results?

My suspicions are the same as another posters - the current draw is dropping the voltage below a threshold setting. I suspect that just using the EVF without the LCD will decrease the overall draw and keep a set of batteries in service much longer. I'm also wondering about the consistancy of the batteries. I use a MAHA 204F and I've noticed that sometimes one pair of batteries finishes charging in a significantly shorter period of time than the other pair. With most of my sets the difference is less than 5 minutes, others seem to be much longer (I have to start timing them). I'll have to swap sides also - I don't know the circuitry of the charger, it might just supply more current to one side.

Some possibilities are 1) different usage patterns, 2) bad
batteries and 3) bad cameras. These are TESTABLE hypotheses (but
not mutually exclusive). Let's hope owners get busy sleuthing and
find their problems. Many people need to be more conservative with
the LCD. A few may have bad batteries and/or bad cameras.

"Bad" batteries may be common. We all know that they are not all the same. One weak cell will drop the entire load. BTW - I bought a set of batteries a couple of weeks ago and one was a dead short (1.5Ω).

NiMH are supposed to maintain a nearly constant voltage, but if
they have not been properly conditioned and the current load is
high, the voltage may fall below a threshold that the camera cannot
accept. I find that my NiMH batteries are functional much longer
after conditioning in my Maha C204F charger. A voltmeter can be
used during operation to determine voltage output vs. time and
camera load, and to discover the threshold voltage at which the
camera shuts down.

When I have time (not this week) I'm going to run several sets to shutdown and check their voltages. I'll bet that the batteries that fail with the LCD enabled have a higher remaining voltage than those used with only the EVF.

It may be the the heavy load of the D7 brings down the voltage more
than with other cameras, but no one has yet posted data by which to
judge this idea. Specifically, we need to know the current demand
of the D7 by the LCD, by the EVF, by the flash charger, and by the
D7's other electronics before and after power save goes on. Armed
with all of this information, owners can better judge the likely
cause(s) of the power problems they are posting on the forum, and
potential buyers such as me can better decide if the D7 is
inherently flawed or just, so far, poorly understood.

Will you volunteer your camera? I promise not to put too many holes in it. I worry about subjecting my camera to voltage from a converter/dc power supply - I don't want to fry it. Someone else will have to plot the actual current draw. Maybe if I get the Minolta battery pack I can hook it up and run tests.

Wayne

 Wayne DeWitt's gear list:Wayne DeWitt's gear list
Minolta DiMAGE 7 Nikon Coolpix P510 Nikon Coolpix P7800 Kodak DCS Pro 14n Nikon D70 +2 more
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