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12-12-2011, 01:10 AM - 1 Like   #1
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eneloop (Duracell Pre-Charged) long term report (2+ years)

On November/24/2009 I got a Pentax K-x dSLR to replace my K100D.
So the K100D got relegated to a backup.

I kept the set of Duracell Pre-Charged (DP-C - made in Japan, white top - confirmed eneloop re-badges) in the camera




Those were topped up charged on Jul/8/2009 and placed in the K100D on Oct/6/2009 (during a shooting session).

The K100D was "retired" after 623 shots had been taken on this set of DP-C.

The K100D has more or less been idle except for a few shots here and there since Nov/24/2009.

Since this has been over 2 years since it was retired I thought I'd see the remaining capacity of these DP-C. The total number of pictures I took over the "idle" 2+years was just 115.

Note should be made a few months ago I turned on the K100D (a few months shy of two years of being idle) - the top LCD panel came on, but the camera did not respond as expected - I had to turn the camera on/off a few times - then it did work OK - so either the camera needed to "wake up" charge up capacitors etc - or the batteries needed "waking up" - I do not know - but it is worthwhile noting.

Today Dec/12/2011 after a total of 738 shots - 623 of which were in the first month after battery installation - with the camera mostly idle and only very occasional usage -
Maha C-9000 discharge at 400mA (=1/5 or 20% capacity current) -
Remaining capacity and discharge times:

472 mAh (78min)
485 mAh (81min)
461 mAh (76min)
455 mAh (76min)

This looks pretty impressive to me as it is nearly 2.5 years (2 years 4 months 24 days) since charge - and there seems to be still nearly 1/4 capacity, also having taken 738 shots -

Extrapolating this - it means a theoretical shot count of 955 shots
(I used the lowest 455 mAh remaining capacity, and 2000mAh as the full capacity -
worst case figures).

Just to put this into context I was getting on average 1,000 shots/charge -
so having these DP-C idle for nearly 2.5 years since charge does not seem to have reduce the theoretical shot count.......

Comments?

12-12-2011, 10:45 PM   #2
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I'm guessing the camera would turn off before you could use all the remaining 455 mAh. I don't know about K100D, but I need to push my K-x through several automatic turn-offs before the eneloops are completely drained.

Nevertheless, very impressive.

It also implies there's negligible power drain in the power off position.
12-13-2011, 12:06 AM   #3
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QuoteOriginally posted by OutOfFocus Quote
I'm guessing the camera would turn off before you could use all the remaining 455 mAh. I don't know about K100D, but I need to push my K-x through several automatic turn-offs before the eneloops are completely drained.

Nevertheless, very impressive.

It also implies there's negligible power drain in the power off position.
Thanks.

I normally shoot until the camera turns off - and more often than not, I simply turn the camera off and back on, to continue, just because the camera turns off normally when I'm about to take a shot, I also usually keep shooting until the camera turns off again, before I change batteries.

The lowest safe voltage for NiMH cells is supposed to be 0.9V

Standard discharge current for capacity measurement is 1/5C or 20%C.
I use the Maha/PowerEx C-9000 at the standard discharge current of 400mA to measure remaining capacity (to 0.9V) after I get home on a depleted set.

Unfortunately I did not own the Maha C-9000 while I was active with the K100D to have remaining capacities for it -
but in the K-x, over 2+ years and 36 changes with 3 sets of eneloops/Duracell Pre-Charged -
the highest remaining capacity was 70mAh and the lowest was 0mAh(!) the latter probably was not so good for the battery -

This shows that the K-x is pretty good at draining the batteries -

or more to the point eneloops maintain their operating voltage under-load to above 1.15V per cell
so that the K-x (and K100D) will continue to operate.

The shutdown threshold total voltage (4 batteries in series - tested for the K200D) is ~4.6V.

EDIT to ADD -

There ought to be some power usage when idle, to keep the clock running.

Last edited by UnknownVT; 12-13-2011 at 10:56 AM.
12-13-2011, 04:53 PM   #4
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Good testing, made for a good read, thank you.
Just that... Jurassic park came to mind when reading it. Maybe the dinosaurs should be left sleeping.

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