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01-11-2009, 05:52 PM   #31
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Just so that I am not entirely biassed toward eneloops - some conventinal high capacity NiMH batteries will outperform eneloops if they are recently charged (ie: not stored for too long before actual usage).

Here are the comparisons - again using the discharge curves by SilverFox taken from NiMh Battery Shoot Out

I drew the same horizontal 1.15V threshold cutoff red-line
then noted the points at which the 2Amp and 1Amp discharge curves crossed that red-line and found the mid-point between those (this should approximate where a 1.5Amp curve would cross the 1.15V red-line - not exactly right but probably close enough for this look-see comparison)
and dropped a vertical red-line to the horizontal axis to note the actual Amp-Hours delivered.

eneloop


Sanyo 2700 mAh


Duracell 2650 mAh


those readings were approx

Sanyo 2700mAh = 2.265 A-h
Duracell 2650mAh = 1.881 A-h
eneloop = 1.66 A-h
Energizer 2500mAh = 1.61 A-h
GP ReCyko = 1.54 A-h
RoV Hybrid = 1.43 A-h

So the high capacity Sanyo 2700 mAh and Duracell 2650 mAh do beat the eneloop when they are recently charged and in good condition.

However when aged high capacity NiMH are notorious for developing high rates of self-discharge and can lose their capacity (eg: Ref1 Ref2) -
so that the LSD (Low Self-Discharge) batteries eventually will cross-over and perform better in longer storage before use situations.

To be fair when one is going to use the K100D/K200D a lot - then charging up a set of those high capacity NiMH on the day or night before probably will show better performance from eneloops under the same conditions.

But if the batteries are stored or unused for anything over a month or 2, then the eneloops are probably going to do better at that point.


Last edited by UnknownVT; 01-13-2009 at 09:38 PM. Reason: typos
01-13-2009, 09:04 PM   #32
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For those who may be technically minded - there is now a wealth of information on eneloop.info -

I got these from a post by Bones on CPF
Eneloop - Performance Details for Experts

Pasted here for your convenience -


Cover - an Overview

Capacity - Nominal, Stored and Under Discharge

Self-Discharge - Capacity, Voltage and Higher Temperatures

Discharge Currents - Performance at Higher Currents

Low Temperature - Discharge at Low Temperatures

Voltage - Operating Voltage and DSC Settings

Cycle Life - Cycle Characteristics and Comparison

Technology - Construction and Self-Discharge Reduction

Q & A - Eneloop Questions and Answers

A very detailed .pdf document entitled 'Development of Low Self-Discharge Nickel Metal Hydride Battery' from the Sanyo Technical Marketing Department:

http://www.eneloop.info ... editors.article.pdf


The most relevant section is -

Voltage - Operating Voltage and DSC Settings

where they show how the eneloop maintains its voltage above most digicam's cutoff voltage -
.... hello K200D and K100D.....
01-13-2009, 09:37 PM   #33
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As a long time user of Eneloops, I think I was one of the first on here to do so, here is my 20 cents worth.

Bought a *ist DS in early 2005 and ran it on Rechargeable Eveready's. That was fine until I put the camera down for a wek or so, batteries were always flat when I wanted to use it.

Thus the search for something else, which initially was Lithiums, but then stumbled across Eneloops.

I have used Eneloops ever since, now running four (4) sets. On a recent trip the K200D battery life was just as good as the K20D.

I can not reccommend Eneloops enough, I simply have not had any battery issues since making the switch.

Cheers
Grant

PS: yes the battery meter will show empty after continuous heavy use, but switch it off for a bit and they seem to recover. I have milked several days extra out of my batteries doing this, even with lithiums.
07-10-2009, 08:37 AM   #34
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QuoteOriginally posted by UnknownVT Quote
A very detailed .pdf document entitled 'Development of Low Self-Discharge Nickel Metal Hydride Battery' from the Sanyo Technical Marketing Department:

http://www.eneloop.info ... editors.article.pdf
Appears that link is dead. A similar link can be found here for the document.

10-25-2009, 10:06 AM   #35
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Very, very interesting thread, indeed. There has been talk elsewhere about a number of Kx's with this very same problem.

One wonders what the tolerances are for the battery-flat-o-meter - I suspect I have a K200D in which the cutoff voltage is a little too high. It works great once the batteries have warmed up a little (i.e. 20-30 shots), before that it'll show half charge, and once in a while, will actually shut down. I also wonder if this is user-settable via secret menu or if you actually have to physically tweak a potentiometer somewhere in the camera body.

I've heard it said elsewhere (can't remember where) that the cameras were not really designed for NiMH cells, but for the 1.5 volt lithium primary cells made by Energizer. (Incidentally, CR-V3 primary lithiums are just two AA cells packaged as one - no need to buy them since they cost far more than two AA cells.) The lithiums give faster focusing, among other things, due to their 1.5 volts (rather than the nominal 1.2 of the NiMH cells). The battery-flat-o-meter would work well with them.

I wish I could get a set of the new Ni-Zn cells - their voltage is 1.6 fully charged, they might give the same benefits of the Li cells (and you can recharge them). They're on Amazon, but shipping here would cost an arm and a leg, and I'd rather have my arm and leg.

Any word on Pentax's official line on these? They warn against using RCR-V3s (these are 3.7 volts, while the primary lithium CR-V3s are 3.0).

Iskandar
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