Nikon D300 forgets time

Is there a second battery I don't know about? My Pentax *ist D has a CR2016
in the base. Canon dSLR have a CR2016 as well. Does the D300 have a hidden
back-up cell? A friend's D300 forgets what the time and date is, so I
suspect a battery issue internally.

On Mon, 8 Dec 2008 11:30:10 -0500, wrote:

Is there a second battery I don't know about? My Pentax *ist D has
a CR2016 in the base. Canon dSLR have a CR2016 as well. Does the
D300 have a hidden back-up cell? A friend's D300 forgets what the
time and date is, so I suspect a battery issue internally.

You're correct, it's well hidden. The internal rechargeable
battery is either defective or it's not being properly charged.
Your friend may need to have the D300 serviced.

This is from page 38 of the D300's manual :

¤ The Clock Battery
The camera clock is powered by an independent, rechargeable power
source, which is charged as necessary when the main battery is installed
or the camera is powered by an optional EH-5a or EH-5 AC adapter
(pg. 364). Two days of charging will power the clock for about three
months. If the B icon flashes in the control panel, the clock battery is
exhausted and the clock has been reset. Set the clock to the correct time
and date.

ASAAR wrote:
On Mon, 8 Dec 2008 11:30:10 -0500, wrote:

Is there a second battery I don't know about? My Pentax *ist D has
a CR2016 in the base. Canon dSLR have a CR2016 as well. Does the
D300 have a hidden back-up cell? A friend's D300 forgets what the
time and date is, so I suspect a battery issue internally.

You're correct, it's well hidden. The internal rechargeable
battery is either defective or it's not being properly charged.
Your friend may need to have the D300 serviced.

This is from page 38 of the D300's manual :

¤ The Clock Battery
The camera clock is powered by an independent, rechargeable power
source, which is charged as necessary when the main battery is installed
or the camera is powered by an optional EH-5a or EH-5 AC adapter
(pg. 364). Two days of charging will power the clock for about three
months. If the B icon flashes in the control panel, the clock battery is
exhausted and the clock has been reset. Set the clock to the correct time
and date.

That seems to be to be somewhat of a black mark against D300 and
possibly other Nikon cameras if they use the same system.

Given the life of a rechargeable is about five years if you are lucky,
and the very low drain of clock chips, other cameras' use of lithium
button cells like the 2016 will get at least that long a life and
probably more without the need to recharge at all.

And the time limit of about three months before recharging or else have
the clock reset to zero is just ludicrous in a camera of that quality.
A lithium cell has no such limitation. I wonder if they are using a
very large capacitor in the Farad range instead of a secondary cell for
the clock application?

Colin D.

On Tue, 09 Dec 2008 10:55:37 +1300, Colin.D wrote:

That seems to be to be somewhat of a black mark against D300 and
possibly other Nikon cameras if they use the same system.

I agree. Sometimes resetting a device is needed, but impossible
to accomplish when the device's CPU crashes or goes haywire. Reset
buttons don't always trip an interrupt line. Sometimes they're
connected to an I/O port and require a functioning CPU to see that
the button was pressed by polling the port. Nobody would want to
wait 3 months (or more) for the battery/supercap. to run down.


Given the life of a rechargeable is about five years if you are lucky,
and the very low drain of clock chips, other cameras' use of lithium
button cells like the 2016 will get at least that long a life and
probably more without the need to recharge at all.

While I'd prefer that Nikon's DSLRs used lithium button cells, I'm
overly troubled that they don't. I've known of several portable
phones that used NiCd batteries and that retained about 30% of the
original capacity they had, 7 or 8 years later. If the D300's
internal battery/cap. had only 10% of its original capacity after 10
years, I'd still have more than a week to recharge its EN-EL3e.

On Tue, 09 Dec 2008 10:55:37 +1300, "Colin.D" wrote:


Given the life of a rechargeable is about five years if you are lucky,
and the very low drain of clock chips, other cameras' use of lithium
button cells like the 2016 will get at least that long a life and
probably more without the need to recharge at all.

Depends on the technology... a Dallas internal battery ROM has a life of over 20
years, I know because systems I installed in the 80s are still working... when
the battery's finally die, the systems will die. I would imagine today's
technology is better...