# eneloop vs. Kodak Pre-Charged Voltage Maintenance



## UnknownVT (Apr 4, 2008)

I have both eneloops and Kodak Pre-Charged LSD in AA size for use in my Pentax K100D dSLR.

This dSLR is well known to be very battery fussy - 
Ref: Post #*49* (link) in thread - K100D - "Low-Battery" Problem gives details of the meter voltage levels.

The poster measured these voltage levels for the Pentax K100D dSLR -
Battery meter shows full charge at > 1.25v per cell, i.e. >5.00v
Battery meter shows half charge at 1.25v per cell, i.e. 5.00v
Battery meter shows empty and camera shuts down at 1.19v per cell, i.e. 4.76v

On Mar/31 I checked my back-up set of 4x Kodak Pre-Charged AA's - showed full charge when first inserted, but after taking a single test shot - they showed half charge on the camera's meter.

These Kodak Pre-Charged were charged 4 months ago (New Years Eve) - I also charged a set of 4x eneloops at the same time.

In comparison the eneloops were actually in the camera and continued to show full charge level despite having been used more - albeit only occassional ad-hoc shots - but substantially more than the few test shots for checking the Kodak P-C.

Here were my measurements -

Kodak P-C that showed half charge -
#5 - 1.315V, FA=9.0A, 1.301V
#6 - 1.314V, FA=9.0A, 1.309V
#7 - 1.315V, FA=8.5A, 1.300V
#8 - 1.314V, FA=8.8A, 1.304V

these actually look pretty healthy - 
and seems they still have a _LOT_ of charge in them.

Contrast with the 4x eneloops which had been used a bit more and were kept in the camera - reading taken Apr/3 after a short photo session -

eneloop - used more, but still shows full charge -
#1 - 1.294V, FA=9.85A, 1.285V
#2 - 1.294V, FA=10.29A, 1.285V
#3 - 1.294V, FA=10.29A, 1.283V
#4 - 1.293V, FA=10.10A, 1.283V

FA= "Flash Amps" - the second Voltages are taken after the FA.

Notice all the open-circuit voltages for the eneloops are lower than the Kodak Pre-Charged - which indicates that these probably are in a lower state of charge than the Kodak P-C.

BUT despite that, the eneloops continue to show full charge on the Pentax dSLR, whereas those Kodak P-C show half charge.

This tells me that the eneloops seem to maintain a higher voltage level _Under-Load_ than the Kodak Pre-Charged.

So it is possible for the Kodak P-C to show empty or even have the camera shut-off when they may still have substantial charge remaining.

This is *NOT* saying the Kodak Pre-Charge has low capacity, or self-discharges quicker -
in fact the few tests I have seen the Kodak P-C appear to have one of the highest capacities of all LSDs -

But this is a very good illustration of possible higher voltage maintenance of the eneloops over the Kodak Pre-Charged.

Uniross Hybrios are also said to maintain higher voltage levels - the poster in the dSLR thread uses and suggests that - 
Chevrofreak claims this too in Post #*15* of thread - My Eneloops charge to and hold a higher voltage than other LSD's ... - 
he also did some runtimes in a flashlight comparing the Kodak P-C and Hybrio - in posts #*13* and #*14* in the thread - new Kodac "Pre Charged" NiMH batteries? - which shows that the Kodak P-C have noticably better capacity/runtime in a flashlight over the Uniross Hybrios.

So it appears that the Kodak Pre-Charged do have good capacity - 
but the eneloops maintain higher voltage levels - 
and this is important for my use in the Pentax K100D dSLR - 
since it is battery voltage sensitive.

I think I'll use my Kodak Pre-Charged for flashlights,
and use eneloops for the dSLR.

_*EDIT to ADD*_ -
Further testing/thoughts - 
Kodak Pre-Charged matched eneloops literally step-by-step in unregulated and regulated flashlights see posts #*11* and #*27* (links)
... and to my chagrin, and pleasent surprise, seem to do as well even in my battery fussy Pentax K100D dSLR see Post #*39* 
(not yet fully proven - but their performance so far have been very good)

Summary of results in Post _#_*57*https://www.candlepowerforums.com/posts/2497499&postcount=50


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## gunga (Apr 4, 2008)

Any info on the hybrids? This is pretty interesting since all these LSD cells may be made by only a couple factories.

I wonder if it boils down to the Japanese Sayno/Duracell vs Chinese Hybrid/Kodak etc cells? 

Or maybe not, just a theory.


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## Mr Happy (Apr 4, 2008)

That's interesting data.

I have made a few spot tests of internal resistance for Eneloops and the Kodak PC cells. I found the Eneloops to measure in the range of 40-50 milliohms, and the Kodaks in the range of 110-120 milliohms. This would be consistent with the Kodaks having a greater voltage depression under load.

Since you mentioned cell voltages I just pulled the Eneloops out of my camera (a Canon A620) and measured them. They are reading 1.27 V and the camera is working fine with no low battery indication.


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## UnknownVT (Apr 4, 2008)

Mr Happy said:


> I have made a few spot tests of internal resistance for Eneloops and the Kodak PC cells. I found the Eneloops to measure in the range of 40-50 milliohms, and the Kodaks in the range of 110-120 milliohms. This would be consistent with the Kodaks having a greater voltage depression under load.
> I just pulled the Eneloops out of my camera (a Canon A620) and measured them. They are reading 1.27 V and the camera is working fine with no low battery indication.


 
I would tend to agree with you - the lower flash amps readings on the Kodak Pre-Charged would also hint at the higher internal resistance than eneloops.

I have found Canon A-series digicams (I have owned two, and the A610 is my current digicam to take my beamshots) to be very tolerant and frugal with batteries - almost the opposite to the Pentax K100D dSLR which is pretty fussy and voltage sensitive.

So, it is not the open-circuit voltage levels - 
since the Kodak Pre-Charged showing half charge in the Pentax K100D dSLR actually had higher o-c Voltages (even after the short but harsh treatment of "Flash Amps") than the eneloops - used significantly more, but still showed full charge.

Here's my version of the battery ends comparison -






and a recent thread of relevance -

[Slightly OT] Cutoff voltage of cameras favors Low Self-Discharge batteries?


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## eluminator (Apr 4, 2008)

100 ohm internal resistance indicates bad NiMH cells when I measure them. Maybe there is something wrong with my measurement technique, but I'm willing to bet those are bad cells and won't work in a high load device like a camera.

I get 30 to 40 ohms with charged good NiMH AA cells.


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## UnknownVT (Apr 5, 2008)

I had to go out to shoot a session yesterday - which I had forgotten about until literally a few minutes before I had to leave the house - so I could not charge up my set of 2500mAh regular NiMH (non LSD).

So I used the set of eneloop that were already in the Pentax K100D dSLR - I took over 50 shots - probably about 2/3-3/4 with flash which is very demanding on the batteries -even after extensive reviewing of the photos - these eneloops are still showing full-charge on the dSLR's indicator.

The readings I got later were -

eneloops -
#1 1.287V, FA=9.60A, 1.280V
#2 1.287V, FA=9.50A, 1.281V
#3 1.287V, FA=10.27A, 1.278V
#4 1.287V, FA=10.18A, 1.277V

All the open-circuit voltages were obviously lower than the ones in the opening post, but the ones taken after the "Flash Amps", although also lower, were still around ~1.28V - open-circuit - these still manage to show full-charge on the Pentax K100D whereas the Kodak Pre-Charged as I reported previously, at above 1.3V o-c started to show half charge.

For those more observant eneloop #4 seems to show a higher Flash Amps than before with more charge.... This is probably due to experimental tolerances - as the Flash Amps are never that precise for me -they do not normally show a steady state - but the numbers fluctuate on my cheapo DMM - I just use a sort of "average".


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## Mr Happy (Apr 5, 2008)

Eneloops are rather good, aren't they?

What you did is what I usually do. Rather than specially charging up a set of cells before using the camera, I just use the Eneloops already in the camera and take a spare set along with. Two sets of Eneloops will last for more pictures than I can possibly take in one outing.

If I bought a DSLR I'd really like one that takes a set of 4 AA cells. They are much more flexible and interchangeable than the built-in lithium battery usually provided.


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## UnknownVT (Apr 5, 2008)

Mr Happy said:


> Eneloops are rather good, aren't they?
> 
> What you did is what I usually do. Rather than specially charging up a set of cells before using the camera, I just use the Eneloops already in the camera and take a spare set along with. Two sets of Eneloops will last for more pictures than I can possibly take in one outing.


 
Yes, I agree - and I am likely to just use eneloops in the dSLR - with a spare set - like you are doing.

Watching the battery meter yesterday during my shoot, and seeing full-charge all the time, I was beginning to think these eneloops were going to last "forever".

However, I wonder if they might go from showing full charge to depleted/shut-off without much warning, ie: sudden drop-off?

The only thing is that I am now "somewhat" disappointed with the Kodak Pre-Charged - since I have always regarded them as "the same" as eneloops.

In other uses, like flashlights, they do seem every bit as "good" as eneloops, with possibly higher capacity - 
but it's in this area of voltage maintenance that they perform less well than eneloops - 
and that is precisely the critical area for the Pentax K100D dSLR.

So in terms of voltage maintenance - and specifically for use in the Pentax K100D dSLR the Kodak Pre-Charged are simply not as good as eneloops.

Ref: eneloop actually claims higher voltage maintenance on their Canadian site


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## Kankujoe (Apr 6, 2008)

Would these findings hold true for the Duracell pre-charged LSDs (produced in Japan) vs the Duracell pre-charged LSDs (produced in China)?

Thanks,
KJ


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## Mr Happy (Apr 6, 2008)

Kankujoe said:


> Would these findings hold true for the Duracell pre-charged LSDs (produced in Japan) vs the Duracell pre-charged LSDs (produced in China)?


I don't wish to spend money on any black top Duracell made in China cells to find out.

What I can say is that to the best of my testing ability the Duracell LSDs with the white top, made in Japan, perform the same as Eneloops. The same also goes for the Uniross Hybrios with the white top, although those say they are made in China.


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## UnknownVT (Apr 20, 2008)

Here's an ad-hoc experiment to try to highlight voltage maintenance difference between eneloop and Kodak Pre-Charged -
_BUT_ it gave an unexpected result.

I wanted to see discharge in a flashlight that has a relatively high threshold/cut-off voltage.

Background - 
I have two Dorcy 45lumen 1AA (41-4253) -
one was a "replacement" (#2) when I thought the first one I had (#1) had an intermittent switch - 
in fact it was _not_ a faulty switch - it was the relatively high threshold/cut-off voltage that prevented the light from switching on, when there was still charge in the battery I was using.

For some discussion of this high threshold/cut-off voltage please see Post #*37* (link) in
Dorcy 45 lumen 1x AAA Comparison Review

#2 has a marginally higher cut-off voltage than #1 - 
about 1.3V vs. 1.27V on batteries measured open-circuit when the light would not turn On. A battery that just would not turn On in #2 can still turn on #1.

So for this ad-hoc test I charged up one eneloop and one Kodak Pre-charged AA let them rest for about 15 minutes and took their readings.

eneloop ... 1.467V; FA=11.2A; 1.447V
Kodak P-C 1.445V; FA=10.6A; 1.429V

eneloop in #2 (slight _DIS_advantge) and Kodak P-C (slight advantage) in #1- since it has been shown eneloop seem to maintain higher operating voltage than the Kodak P-C.

I took a side-by-side comparison beamshot at the start - then allowing the lights to run for approx 4 mins - switch off for 1 min then took another shot when switched back On - repeated until the lights would no longer switch On again.

Results -
at start 00mins, and after 4mins On and 1 min Off/rest - shot taken when switched back On -








at ~47mins, and ~51min the last shot before one light would not switch back On.








after 4 more mins On, then off for 1 min one of the lights would not switch back On -




I was surprised that it was the eneloop that failed to switch back On since I have shown it maintains Higher operating Voltage than the Kodak P-C
Running this for 4 more mins and 1 min Off the Kodak P-C then would not switch back on.... So Total On time = ~59mins

However since I reckoned #2 had a higher threshold/cut-off voltage - I then put the eneloop in #1 (lower threshold/cut-off) - lo-and behold the light came on -




Running this for 4 more mins and 1 min Off the eneloop then would not switch back on in #1 .... So total On time ~59min

Note times given are accumulated *On* time totals only (the approx 1min Off times were NOT counted).

State of batteries after this test -

eneloop .... 1.179V; FA=2A; 1.046V
Kodak P-C 1.187V; FA=7.5A; 1.143V

The significantly higher Flash Amps of the Kodak P-C tells me there is more charge left in it - whereas the eneloop is pretty close to depleted.

To prove this I put the batteries in turn in a Fenix L1D-Q5 on High (not turbo) and timed how long it would take until No light (~0.9V cut-off)

eneloop ~ 18mins
Kodak P-C ~ 31mins

So the Kodak P-C lasted some 13 mins (72%) longer until depletion in the Fenix L1D-Q5 on High.

Depleted readings -

eneloop ... 0.918V; FA=0.2A; 0.924V
Kodak P-C 0.889V; FA=0.4A; 0.887V

I would say these were fully drained almost on the threshold of being bad for the batteries.

So despite what I first thought was an experiment that gave unexpected results, I can draw these surmises -

In these high threashold/cut-off voltage flashlights there probably isn't any practical difference between eneloop and Kodak Pre-Charged - both will last about 1 hour even if switched off between (note my tests are somewhat "artificial" in running for 4mins On, and 1min Off).

At the point where the Kodak P-C would no longer switch the Dorcy 45lumen 1AA on again, there was more charge left in it than in the eneloop - approx 13 mins more on High in a Fenix L1D-Q5 running until depletion/cut-off in the Fenix. 

This shows that the one sample of the Kodak Pre-Charged has significantly higher capacity than the one sample of the eneloop. 

BUT in a flashlight with a high threshold/cut-off - this is not delivered as the Kodak P-C cannot maintain a high enough voltage to turn the light back on - 
whereas the eneloop can maintain a higher operating voltage so could deliver more of its total capcity.......

This is Not very clear cut - 
but I think my surmising/speculating on this is probably right.......


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## Mr Happy (Apr 20, 2008)

I'd say you have the analysis about right.

The test shows how the important measure of capacity is what is actually delivered in a given application rather than the 'total' capacity of a given cell. There are many circumstances in which you can receive less actual capacity from a cell than what the label says.

I also feel that I will steer clear of that Dorcy light. It seems too sensitive to input voltage. If it were running on an alkaline it would only get half the available capacity out of the cell.

Also note that the voltages you measure are changing with time, so it is a bit like trying to hit a moving target. Give it a few hours and those depleted readings of 0.9 V will rebound back up to about 1.2 V.


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## UnknownVT (Apr 20, 2008)

Mr Happy said:


> I'd say you have the analysis about right.
> The test shows how the important measure of capacity is what is actually delivered in a given application rather than the 'total' capacity of a given cell. There are many circumstances in which you can receive less actual capacity from a cell than what the label says.


 
Many thanks for the affirmation.

However what you say in the second paragraph about delivered capacity - applies to devices with higher voltage cut-off thresholds.

The timed drained tests in the Fenix L1D-Q5 shows that the Kodak P-C can actually deliver noticably more capacity than the eneloop - 
when the cut-off threshold is not too high.

These Dorcy 45lumens 1AA lights, as you point out, probably would only partially drain alkalines, and be unable to switch back on when there is still significant capacity left. 
Whereas a Fenix L1D probably would be able to utilize the battery's capacity better.


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## Mr Happy (Apr 20, 2008)

UnknownVT said:


> However what you say in the second paragraph about delivered capacity - applies to devices with higher voltage cut-off thresholds.


The voltage threshold is not the only factor though. The discharge current, the way the cell is charged, the time since charging and the ambient temperature are all factors that can affect how much capacity you actually see when discharging a cell.


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## UnknownVT (Apr 20, 2008)

Mr Happy said:


> The voltage threshold is not the only factor though. The discharge current, the way the cell is charged, the time since charging and the ambient temperature are all factors that can affect how much capacity you actually see when discharging a cell.


 
Got you. Of course I accede to your better knowledge, and more complete answer.

I meant in this ad-hoc experiment above - it was the higher voltage cut-off threshold that was the main determining factor that had the eneloop and Kodak P-C showing neck-and-neck in terms of usable capacity in the those Dorcy 45lumen 1AA light(s).

However it would seem that the Kodak P-C will show a noticable higher usable capacity in a light that has a lower (more sensible) voltage cut-off threshold such as the Fenix L1D-Q5.


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## Power Me Up (Apr 21, 2008)

Could it also be that the Dorcy isn't fully regulated and so actually draws more current from the Eneloop (because of the higher voltage) causing it to run out sooner?

It might be interesting to compare the run times for the Eneloop and the Kodak in the L1D after they're both fully charged. If the Eneloop maintains a higher voltage, the L1D should draw a lower current from the Eneloop due to the fact that the L1D is fully regulated and could quite likely run longer with the Eneloop even though it has a lower measured capacity.


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## mdocod (Apr 21, 2008)

Of all the NIMH AA cells I have owned, the eneloops are the only cells I can really rely on to take the abuse of my lack-of-care methods. I don't match cells in sets for use in adapters, I don't do break in cycles, I don't keep track of anything, I just have a bin of charged and used cells and run through em. Sometimes slapping cells in a pack and pack charging them, sometimes using them in single cell lights, sometimes grabbing a few to snap a few shots in the Camera. They have proven to be the ONLY NIMH cells that will reliably run my Camera without showing pre-mature low-battery indicators. I have overheated some of these (to the point of melting the wrapper off), left some out in the car on nights below 0 degrees F. charged at rates as high as 6.5A... They just keep on going without much if any negative issues. The eneloop cell is amazing for so many reasons. IMO, it represents the ideal behavior and tolerance of a rechargeable consumer cell. With the right marketing and consumer awareness, cells like these could completely replace most other types of cells on the market.

Eric


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## SilverFox (Apr 21, 2008)

Hello Eric,

:devil: I must warn you that your cruel and torturous treatment of this limited species of cells will not go on without an outcry from seasoned batteryoholics...

I think your behavior should be turned into "Battery Protective Services" as it seems you are unable to provide a suitable environment for the long life and optimum performance of the cells in your care.

Fortunately, the Eneloop cells are robust, but even they have their limits.

Consider this a warning that I will offer no sympathies IF your cells every die. :devil:    

Now, I have to get back to my 15 minute charge testing of these cells...  

Tom


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## UnknownVT (Apr 21, 2008)

Power Me Up said:


> It might be interesting to compare the run times for the Eneloop and the Kodak in the L1D after they're both fully charged. If the Eneloop maintains a higher voltage, the L1D should draw a lower current from the Eneloop due to the fact that the L1D is fully regulated and could quite likely run longer with the Eneloop even though it has a lower measured capacity.


 
This is in fact Sanyo's claim for eneloops - on their Canadian site -

" *Higher Operating Voltage*
_Higher voltage means that Eneloop 2000 mAh batteries will have similar performance to 2500mAh conventional rechargeables._ "

In the Dorcy 45lumen 1AA with the _UN_reasonably High cut-off threshold voltage - the 2000mAh eneloop appears to have the same/similar runtime/capacity as a 2100mAh Kodak Pre-Charged ........

BUT the remaining capacity used in a more reasonably set cut-off voltage of ~0.9V in the Fenix L1D-Q5 showed that the Kodak Pre-Charged had 13mins (72%) more runtime to no light (cut-off) than the eneloop.

So in my example because of the _UN_suitably high cut-off voltage the eneloop does show itself to be as good as at least a 2100mAh LSD......

However if they were put in a lower or more suitable cut-off voltage device/light - the Kodak P-C probably would show better/longer runtime -
see Chevrofreak's runtime of the Kodak P-C vs. Uniross Hybrio - 
in posts #*13* and #*14* in the thread - new Kodac "Pre Charged" NiMH batteries? 
- which shows that the Kodak P-C had noticably better capacity/runtime in a flashlight over the Uniross Hybrios.


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## Black Rose (Apr 21, 2008)

I'd like to try some of the Kodak Pre-charged cells, but cannot find them here at affordable prices like they are in the US.

Wal-mart up here does not carry them at all, and the only local store I found them at wants $20 for a pack of 4 AAs


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## Mr Happy (Apr 21, 2008)

This is quite interesting.

It may or may not be true that the Kodak cells have more capacity, but to test it scientifically we have to measure the run time with all other things being equal.

Many devices like bulbs, and perhaps the Dorcy light, draw more current with a higher input voltage. So with Eneloops the light could run a bit brighter and use the batteries up more quickly, whereas with the Kodaks the light could run less brightly and use the batteries up more slowly.

So to make a scientifically accurate measure of energy storage one must discharge the cell under test in a fully regulated light at constant power so that each cell is being discharged at the same rate.

Now it may be that someone prefers the Kodak to run longer but slightly less brightly, in which case everything is fine. It's good that there are choices out there and that lets someone choose the cell that best fits their application.

(Note: based on chevrofreak's tests, the Kodak cells probably do store more energy than the Hybrios and likely Eneloops, but the increase in brightness with the Hybrios can also be seen.)


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## UnknownVT (Apr 21, 2008)

Mr Happy said:


> So to make a scientifically accurate measure of energy storage one must discharge the cell under test in a fully regulated light at constant power so that each cell is being discharged at the same rate.


 
How do the more sophisticated charger/analysers like the Maha C-9000 that everyone quotes from measure capacity?

If it is in mAh - and not in total energy capacity as in mWatt-hours - 
then how realistic are all the measurements in mAh we have been seeing?


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## Mr Happy (Apr 21, 2008)

UnknownVT said:


> If it is in mAh - and not in total energy capacity as in mWatt-hours -
> then how realistic are all the measurements in mAh we have been seeing?


Using mAh does not tell the whole story, but it is probably realistic enough considering the kinds of load driven by most batteries. Very few devices out there present true constant power loads.

If you look at the numbers, an increase in average discharge voltage of 0.1 volts (say 1.25 V instead of 1.15 V) would equate to an extra 150 mAh on a 2000 mAh cell. Given that even the best cells probably struggle to achieve a 0.1 V higher average voltage, the actual difference is not enormously significant. So the mAh rating is a very close approximation to practical capacity when it comes to real use.

I think mAh was chosen mostly for convenience, perhaps because it is less complicated to measure.


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## UnknownVT (Apr 21, 2008)

Mr Happy said:


> If you look at the numbers, an increase in average discharge voltage of 0.1 volts (say 1.25 V instead of 1.15 V) would equate to an extra 150 mAh on a 2000 mAh cell. Given that even the best cells probably struggle to achieve a 0.1 V higher average voltage, the actual difference is not enormously significant. So the mAh rating is a very close approximation to practical capacity when it comes to real use.


 
Thanks for the explanation - 
and about 0.1V higher voltage maintenance is all that's probably needed for the Pentax K100D dSLR for the difference between showing Full and Half charge - and just enough for the eneloop to show same/similar runtime/capacity as the higher mAh rated Kodak Pre-Charged when used in the Dorcy 45lumen 1AA with _UN_suitably high voltage cut-off threshold.

BTW - the same set of eneloops kept in the Pentax K100D dSLR (very fussy with batteries) since New Years Day - has now taken 258 shots probably with at least 50% flash - and although they did show momentary half battery signal - within seconds they recovered to show full battery - and currently at home they are still showing full battery on the dSLR -

Measurements of the eneloops kept in the dSLR after 258 shots -

#1 1.283V; FA=10.3A; 1.273V
#2 1.283V; FA=10.2A; 1.273V
#3 1.283V; FA=10.4A; 1.275V
#4 1.283V; FA=10.5A; 1.271V

again notice that these eneloops with more use are actually showing higher "Flash Amps" than the previous measurements........


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## Mr Happy (Apr 21, 2008)

UnknownVT said:


> #1 1.283V; FA=10.3A; 1.273V
> #2 1.283V; FA=10.2A; 1.273V
> #3 1.283V; FA=10.4A; 1.275V
> #4 1.283V; FA=10.5A; 1.271V


Those are interesting numbers. I'd estimate that Eneloops reading 1.28 V open circuit are pretty close to empty, so it's impressive they still get such good flash amps and run the camera OK.


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## UnknownVT (Apr 21, 2008)

Mr Happy said:


> Those are interesting numbers. I'd estimate that Eneloops reading 1.28 V open circuit are pretty close to empty, so it's impressive they still get such good flash amps and run the camera OK.


 
You're not kidding - 
after experiencing regular 2500mAh in the dSLR - these eneloops charged over 4.5 months ago with 258 shots duty and lots of reviewing - and after the momentary but "nasty" Flash Amps are still showing full battery on the Pentax K100D - 
for me this is close to a miracle........

(I intend to use these eneloops until shut-down/cut-off in the Pentax K100D dSLR - and will report the total accumulated shots and the measurements then). 

Note: these eneloops have been in the dSLR since New Years day - but I have used the dSLR with regular 2500mAh NiMH when I was still charging up a set on the day of the shoot - 
but since this thread I am now using eneloops exclusively in the dSLR.


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## UnknownVT (Apr 21, 2008)

Crude Runtimes comparing eneloop and Kodak Pre-Charged in Fenix L1D-Q5 on High (general mode, not Turbo) - chosen because it is supposed to be a good regulated light.

Both batteries charged (different ones from the runtime test in the Dorcy) - 
Initial readings -

eneloop ... 1.462V; FA=11.9A; 1.439V
Kodak P-C 1.436V; FA=10.3A; 1.421V

Control reference was a Fenix L1D-RB100 on NiMH also on High, only turned On for the beamshots.

eneloop ................................................................................ Kodak Pre-Charged












































Basically neck-and-neck - the Kodak Pre-Charged for some reason looks a bit brighter at the ~100min (1hour 40mins) and the 105min (1hour 45min) marks, but really for all practical purposes this is a tie.

So my previous speculation that the Kodak Pre-Charged would run longer in a light that has better more sensible cut-off threshold voltage (0.9V) was wrong.

End of runtime readings -

eneloop ... 0.968V; FA=0.4A; 0.956V
Kodak P-C 0.893V; FA=0.4A; 0.878V

Obviously very good performance from the sample of one of the eneloop .....

Having said that, this is also a good performance from the sample of one of the Kodak Pre-Charged - being able to match the eneloop stride for stride - considering by reputation eneloop is probably the "best" of all the current LSD batteries.


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## Power Me Up (Apr 21, 2008)

UnknownVT said:


> However if they were put in a lower or more suitable cut-off voltage device/light - the Kodak P-C probably would show better/longer runtime - see Chevrofreak's runtime of the Kodak P-C vs. Uniross Hybrio - in posts #*13* and #*14* in the thread - new Kodac "Pre Charged" NiMH batteries? - which shows that the Kodak P-C had noticably better capacity/runtime in a flashlight over the Uniross Hybrios.



That doesn't really prove that the Kodak would last longer in an L1D than an Eneloop. The L1P that was used in those graphs isn't fully regulated and so would draw more current from the higher voltage cell causing it to flatten quicker rather than slower as in the case of the fully regulated L1D.

Also, although some people have claimed here that Hybrios are rebadged Eneloops, it certainly isn't the case for all of them - I've got quite a few Hybrios here and can attest that their performance is not as good as the Eneloops that I have.


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## Mr Happy (Apr 21, 2008)

Power Me Up said:


> Also, although some people have claimed here that Hybrios are rebadged Eneloops, it certainly isn't the case for all of them - I've got quite a few Hybrios here and can attest that their performance is not as good as the Eneloops that I have.


Power Me Up: can you take a look at this thread -- When is a Hybrio not a Hybrio? -- and compare your Hybrios with the pictures shown there? I found that the upper cell (that looks like an Eneloop) performs much better than the lower cell (that looks like a Powerex Immedion). The lower cell with the round button and pronounced channel around the positive end performs very poorly in my testing. I'd be interested to know what your Hybrios look like.

Unfortunately since Uniross don't manufacture their own cells, there is no way to be sure exactly what cell is wearing Hybrio clothing.


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## Mr Happy (Apr 21, 2008)

UnknownVT said:


> Basically neck-and-neck - the Kodak Pre-Charged for some reason looks a bit brighter at the ~100min (1hour 40mins) and the 105min (1hour 45min) marks, but really for all practical purposes this is a tie.
> 
> So my previous speculation that the Kodak Pre-Charged would run longer in a light that has better more sensible cut-off threshold voltage (0.9V) was wrong.


Again, a very fascinating test. If the regulated light is drawing less current from the Eneloop due to the higher operating voltage it would go some way to explaining the similar run times.


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## Power Me Up (Apr 21, 2008)

Mr Happy said:


> Power Me Up: can you take a look at this thread -- When is a Hybrio not a Hybrio? -- and compare your Hybrios with the pictures shown there? I found that the upper cell (that looks like an Eneloop) performs much better than the lower cell (that looks like a Powerex Immedion). The lower cell with the round button and pronounced channel around the positive end performs very poorly in my testing. I'd be interested to know what your Hybrios look like.



Mine look like the upper cell - with the black, green and red color scheme.

Although they do have the white plastic around the positive terminal the same as the Eneloops, that's about where the similarity ends - the end surface on the Hybrios is smooth instead of the rough looking surface on the Eneloops. The Hybrios only have 2 vent holes around the positive terminal instead of 4 on the Eneloop and the negative terminals on the Eneloops are very different to the Hybrios. The Hybrios also are labelled as made in China.



> Unfortunately since Uniross don't manufacture their own cells, there is no way to be sure exactly what cell is wearing Hybrio clothing.



It's quite likely that they've used 3 or more different manufacturers...


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## UnknownVT (Apr 21, 2008)

FWIW - runtime of a conventional 2500mAh NiMH - Digital Concepts/Sakar brand from WalMart -
caveat: this tested very poorly for capacity by SilverFox in his NiMh Battery Shoot Out thread scoring -
1.878Ah, 112.7mins, and 2.119Wh
compared to eneloop -
1.871Ah, 112.3mins, and 2.320Wh
pretty similar - but the DC/Sakar are labeled as 2500mAh!!!

Just charged initial readings -

1.410V; FA=10.4A; 1.400V

Crude runtimes on Fenix L1D-Q5 on High (general mode, not Turbo) -

































Notice the first drop off in brightness occurs at between 75-90min - compared to between 96-100mins on either the eneloop or Kodak P-C - so both the LSDs had longer runtimes to the first drop in brightness. 
Then the DC/Sakar drops to almost no light at about 120mins compared to the LSDs at about 125mins, and at 121mins the beamshots still show some light on the LSDs.

So either of the LSDs outperform this conventional NiMH - probably not as labeled 2500mAh - and closer to 1900mAh?

Readings at end of test (longer rest time ~ 40mins) -
1.098V; FA=0.5A; 1.087V


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## Kankujoe (Apr 22, 2008)

Interesting thread! 

Thanks for posting the results and procedures.


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## UnknownVT (Apr 22, 2008)

Power Me Up said:


> That doesn't really prove that the Kodak would last longer in an L1D than an Eneloop. The L1P that was used in those graphs isn't fully regulated and so would draw more current from the higher voltage cell causing it to flatten quicker rather than slower as in the case of the fully regulated L1D.


 


Mr Happy said:


> Again, a very fascinating test. If the regulated light is drawing less current from the Eneloop due to the higher operating voltage it would go some way to explaining the similar run times.


 
Thank you to both Power Me Up and Mr Happy for the explanation -
as can be seen in my crude runtime tests in a good regulated light (Fenix L1D-Q5 on high) the eneloop rated @ 2000mAh matched the Kodak Pre-Charged rated at 2100mAh stride-for-stride. This probably is due to the higher voltage maintenance of the eneloop. 

So my speculation is that even though the Kodak P-C may have higher mAh capacity - the *overall total energy* in mWh (mWatt-hours) are probably very comparable between the eneloop and Kodak P-C 
- ie: the *operating voltage x mAh* are about equal..

It wasn't my intention - but I think this is what my crude runtime in the regulated light has shown?

Again, please correct me if I am wrong or misguided?


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## UnknownVT (Apr 27, 2008)

Mr Happy said:


> Those are interesting numbers. I'd estimate that Eneloops reading 1.28 V open circuit are pretty close to empty, so it's impressive they still get such good flash amps and run the camera OK.


 
Not quite.......

I took my Pentax K100D dSLR out today - almost determined to drain the same set of eneloops until shut-off - 
and they just would not - although there were times when the battery signal showed low - but within seconds it showed half charge and even full charge (although the full charge did not last long).

I took a total of 288 shots today and almost all with flash - which should have drained the batteries quickly - 

So that is in total 546 shots 
(the previous 258 shots since Jan/1 + the 288 shots today) - 
this is quite extraordinary - 
simply counting today's performance would have impressed me.

This is the battery life specs from the manual -






My flash usage today was probably 90-95% - so the total duty cycle was probably way above 50% flash - so the specs for 2500mAh NiMH are 300 for 50% and 260 for 100% - my shot count for today alone was 288.....

Yet just now when I switched On the camera - the indicator showed Full charge - 
after taking one shot (no flash) the indicator was half charge -
I then removed them to take -

eneloop readings -

#1 1.242V; FA=9.9A; 1.234V
#2 1.242V; FA=9.9A; 1.231V
#3 1.242V; FA=9.6A; 1.223V
#4 1.240V; FA=9.5A; 1.229V

After taking these reading (including Flash Amps) - 
the batteries failed to power up the dSLR - 
finally... so I thought.

BUT _UN_believably - when I just checked - with probably only about a 15 minutes rest - the batteries now read half charge again.

I intend to shoot more tomorrow and will report the final count - 
but 548 shots with way more than 50% flash so far - 
- is quite incredible - 
especially since these eneloops were charged back on Jan/1..........


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## Mr Happy (Apr 27, 2008)

Oh, don't be cruel to your Eneloops. Give them a recharge -- don't you think they deserve it by now?


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## UnknownVT (Apr 27, 2008)

Mr Happy said:


> Oh, don't be cruel to your Eneloops. Give them a recharge -- don't you think they deserve it by now?


 
They absolutely _DO_ deserve to be recharged - 
I am so impressed with this set of eneloops :thumbsup:-

But curious minds want to know - 
I really do want to see how many more shots they will do until actual camera shut-off - 
I don't think this will do them any harm - since the camera has a high shut-off threshold - 
surely this can't be any more "harsh" as say the standard capacity discharge testing on the BC-9000? - eg: what are the typical termination voltage levels and "Flash Amps" after that? - 
Remember the o-c voltage of my eneloops even after the flash amps is still over 1.22V.

Anyway, I'll know the count to shut-off hopefully pretty soon


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## UnknownVT (Apr 27, 2008)

UnknownVT said:


> Anyway, I'll know the count to shut-off hopefully pretty soon


 
I used the dSLR today and managed 21 more shots (again mostly with flash) when the camera finally shut-off - so the total accumulated shot count with this set of 4 eneloops charged on Jan/1 was 567 shots a lot with flash - quite a bit more than 50% (as well as several interruptions of flash amps readings). 

For me this was _OUT_standing preformance......as it matches the specifications for using AA _*lithiums*_ with 50% flash usage.

End of experiment readings - used until dSLR shut-off - but rested for about 10 hours -

eneloops -

#1 1.248V; FA=9.9A; 1.234V
#2 1.248V; FA=9.8A; 1.231V
#3 1.246V; FA=9.7A; 1.230V
#4 1.246V; FA=9.6A; 1.229V

With these readings - my guess is that these eneloops might well power up the dSLR again and last for a few more shots - but I considered the test ended when the camera powered-off - so they are finally getting their well deserved charge right now

Perhaps like these eneloops that never seem to die... 
this thread might be following a similar path......

Now a _BIG_ surprise -

I also packed a set of Kodak Pre-Charged (along with my second set of eneloops) since I knew that first set of eneloops were near depletion.

Just for the heck of it I thought I'd put those Kodak P-C in to see how long before I see the half charge signal.

Now these Kodak P-C were charged March/31 - when I discovered after a single shot they displayed half charge - except two which were used in the flashlight runtime/discharge experiments above - so were charged on Apr/20 and 21.

These Kodak P-C took 283 shots today again mostly with flash - and although I did see momentary half charge signal - the indicator bounced back to full charge signal within a second or two.

1) this is obviously a very pleasent surprise,
2) makes me wonder why these Kodak P-C showed half charge as in the opening post - when they held up so well today during actual usage in the dSLR which is very voltage sensitive. 

My speculation(s) -
(a) the Kodak P-C did not hold their charge that well after only about 4 months.
(b) Perhaps my charge of these Kodak P-C was not really full and only partial - since I was using my old cheapo charger back on Jan/1 - but then those eneloops were charged with the same charger - and with the performance I got it's hard to believe the eneloops were not not nearly fully charged.
(c) I was too hasty in declaring the Kodak P-C only showed half charge after only a single shot - perhaps given just a little rest they would have bounced back to full again? - as today's actual hard usage seem to show.

Anyway I am now less "disappointed" with the Kodak Pre-Charged - 
in fact I am actually quite impressed (for now).

I'll leave these Kodak P-C in the dSLR and keep track of the shot count until shut-off.


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## UnknownVT (May 5, 2008)

UnknownVT said:


> My speculation(s) -
> (a) the Kodak P-C did not hold their charge that well after only about 4 months.
> (b) Perhaps my charge of these Kodak P-C was not really full and only partial - since I was using my old cheapo charger back on Jan/1 - but then those eneloops were charged with the same charger - and with the performance I got it's hard to believe the eneloops were not not nearly fully charged.
> (c) I was too hasty in declaring the Kodak P-C only showed half charge after only a single shot - perhaps given just a little rest they would have bounced back to full again? - as today's actual hard usage seem to show.
> ...


 
FWIW I used the Pentax dSLR yesterday and took 203 shots - although mostly with_OUT_ flash - so my accumlated shot count on this set of Kodak Pre-Charged is now 486 and the battery indicator is still showing full charge (although again I did see momentary half charge but this recovered to full, a few seconds later).....

This is close to a "miracle" on the Pentax K100D dSLR - as the specs for NO flash count is only 430 shots using 2500mAh NiMH - my total accumlated shot count of 486 is probably with about 50% flash (spec'd at 300 shots) - this is still 62% over the specs.

This hasn't yet matched the sterling performance of the set of eneloops -
but things seem to be looking good.

There are differences between the usage of these Kodak P-C and the reported eneloops -

eneloops - were mostly unused but kept in the camera (since Jan/1) - other than the occassional test and a few random shots - their first hard use was about 4 months later. (That is when I discovered this set of Kodak P-C charged at the same time although would show full charge when switch On - dropped to half charge signal after taking a single test shot without flash). Also I used a lot more flash with the eneloops as reported above.

Kodak P-C were more recently charged before use (2 (#7&8) charged about 4 weeks earlier, and the other 2 (#5&6) only about 1 week) - 

Charging also was with a more informative/smarter charger - the Soshine SC-C3 Intelligent Rapid Charger vs. the jWIN fast charger used with the eneloops and the earlier report on these Kodak P-Cs. 

First session of 286 shots was using a lot of flash probably 90-95%. Second session very few flash shots. 

Fewer Flash Amps readings with these Kodak P-C during this run than with the eneloops.

The Kodak P-C are still showing full charge and their measurements are -

#5 1.281V; FA=9.3A; 1.275V } more recently
#6 1.281V; FA=9.3A; 1.275V } charged pair
#7 1.269V; FA=9.3A; 1.263V
#8 1.268V; FA=9.3A; 1.263V

The dSLR did show half charge when I returned these after the readings - but after taking a single test shot - the indicator bounced back to full charge.

So for now I am starting to feel these Kodak P-C may perform as well as the enloops - there may be an absolute difference - but in all practicality - the Kodak P-Cs seem to be on their way to matching the eneloop performance.

Perhaps as the runtime tests in the well regulated flashlight (Fenix L1D-Q5) has shown - the eneloop and Kodak P-C seem to have about equal total energy capacity (Watt-hours) even though the spec'd mAh capacities are different - so should give pretty close performance.


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## UnknownVT (May 13, 2008)

I was playing around with a Kodak Pre-Charged in the Dorcy 45lumen 1AA light (with relatively high voltage cut-off) used in my ad-hoc runtime tests for these batteries in Post #*11* , and had these observations.

Kodak Pre-Charged (#2) 1.268V open-circuit -
failed to turn the Dorcy 45lumen 1AA On.

This was with the battery at room temp - "cold".
But warming the battery in my hand for a few moments only, I tried it again in the flashlight and it came On - I took it out immediately
1.266V o-c - a lower voltage but turned the light On.
Returned the battery to the light and it continued to work OK.

I continued to run the light at 4 mins On and 1 min Off like the test in Post #*11* - this gave a chance for the voltage to drop below the relatively High threshold cut-off level of the light.

I took reading at the end of each 4 min On period -
The last voltage taken before the light would NOT turn on again was at 1.190V - the voltage previous to that was 1.212V.

The battery recovered from 1.190V to as high as 1.219V but still failed to turn the light back On.

So my speculation is that the light is not just depenedent on the voltage threshold - but probably needed enough "juice" energy to kick-start the circuit - so the Kodak Pre-Charged at 1.268V o-c but "cold" failed to turn on the light - BUT warming the battery up momentarily in my hand probably "activated" the chemicals in the battery to deliver more "juice"/energy - so even a lower voltage at 1.266V down to as low as 1.212V would still turn the light On.

Note the light runs warm - so the battery feels warm to the touch when readings are taken - and I suspect is still somewhat warm 1 minute later when I try to turn the light back On (corroboration - the lowest voltage when the light still turned On afterwards was 1.212V - however when the battery recovered from 1.190 to 1.219V but probably cooler - it failed to turn the light on.)

So a difference between cold and warm battery.

Wait there is more....

Just out of interest I tried the now drained Kodak P-C in the Fenix L1D-Q5 well regulated light turned on High for 4 minutes and then off for 1 minute - the light then would come on Low and can be changed to Medium level but failed to light up at High - 

Running the light on Medium I saw it dimming. Turning off, then it failed to turn back On - o-c voltage = 0.889V but rising........ 
rested for a few minutes the voltage rose just > 1.0V - and the battery would turn the light back On again and would manage to go to medium level - but not high - then fail to turn on again o-c voltage <0.9V; rest the battery would rise above 1.0V and would turn light On again etc. 
I then stopped torturing the battery.

This observation showed the battery would drain to below the threshold cut-off voltage of the Fenix L1D-Q5 spec'd at 0.9V - and so fail to turn the light back On - however after some moments of rest the o-c voltage would recovered to above 1.0V so able to turn the light back on again, but when drained - did not have enough energy to run then light on High.


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## UnknownVT (May 15, 2008)

One of the things that has me floundering is that I am not able to take the right metrics/meausrements when it comes to batteries.

For example I report on voltages - but they are open-circuit readings which are obviously not as useful or meaningful as the actual operating voltage under load. 

This became pretty obvious to me when I was trying to determine the actual threshold cut-off voltage of the Dorcy 45lumen 1AA flashlight - I could only report on the open-circuit voltage before or after the runtime tests - but not during, when the battery was being used in the flashlight.

I wanted to be able to determine the operating voltage under load for the Kodak Pre-Charged and eneloop to see if there was a difference.

So I thought of a pretty simple somewhat artificial method, but should be easily controlled and reproducible -
just get a 1 ohm resistor and read the voltage when the resistor was loaded across the battery terminals.

To start this I charged one each of Kodak P-C and eneloop AA and then allowed them to rest and cool down for approx 2 hours -

Open-Circuit readings -
eneloop #1: ... 1.454V; FA=11.6A; 1.436V
Kodak P-C #1: 1.423V; FA=10.4A; 1.409V

1 ohm load readings -
ene = 1.388V @ 1.25A (= 1.735watts)
KPC = 1.336V @ 1.22A (= 1.630watts)

End of test o-c readings
ene = 1.440V
KPC = 1.412V

Under a 1 ohm load - eneloop maintained 0.052V higher than the KPC, which is about 4% higher voltage.

From open-circuit voltages (3 sets) the actual differences were 0.031V; 0.027V; 0.028V higher for eneloop - which is about 2% higher for eneloop in all 3 sets.

So this shows that not only is the voltage higher for the eneloops under the same conditions - the KPC sags more _under-load_ than the eneloop.


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## Mr Happy (May 15, 2008)

That's a good way to test cells. 

From those numbers you can estimate the internal resistance of each cell:

Eneloop = (1.440 - 1.388) / 1.25 = 0.0416 ohms
Kodak = (1.412 - 1.336) / 1.22 = 0.0623 ohms

Your Kodak result is quite good. I measured more like 0.1 ohms with a similar test. How many charge/discharge cycles had your Kodak cell been through before you tested it?

You could try the same thing with partially discharged cells for a comparison. You might see a greater relative voltage drop in that situation.

For an even more representative measurement of the internal resistance you can use two different resistors, e.g. 1 ohm and 2 ohms. The internal resistance calculation then becomes:

Internal resistance = (V2 - V1) / (I2 - I1).


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## Black Rose (May 15, 2008)

I love this forum...you learn so much.


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## UnknownVT (May 16, 2008)

Mr Happy said:


> For an even more representative measurement of the internal resistance you can use two different resistors, e.g. 1 ohm and 2 ohms. The internal resistance calculation then becomes:
> Internal resistance = (V2 - V1) / (I2 - I1).


 
Actually I bought a pack of 2 (Radio Shack) 1 ohm 10watt 10% wirewound resistors so I can easily get 2 ohms (series).
Using the same batteries as in the 1 ohm test above -

2 ohms (series) -
ene = 1.400V @ 0.67A
KPC = 1.360V @ 0.65A

Using the 1 and 2 ohm readings and your formula
Internal resistances -

ene Rb = (1.400-1.388)/(0.67-1.25) = -0.021 ohms
KPC Rb = (1.360-1.336)/(0.65-1.22) = -0.042 ohms

These seem very good/low??

I can also get 0.5 ohms by using the resistors in parallel -

0.5 ohms (parallel)
ene = 1.328V @ 2.26A
KPC = 1.264V @ 2.16A

ending open-circuit voltage 
ene = 1.421V
KPC = 1.390V

I thought Internal resistance was the way you originally calculated it 
Rb = (Vs-V)/I
Vs = open-circuit voltage
V = voltage under load
I = current supplied to load.

However as can be seen the open-circuit voltage has dropped after my tests for both batteries.

Using this formula 
2 ohm readings -
ene Rb = (1.421-1.400)/0.67 = 0.031 ohms
KPC Rb = (1.390-1.360)/0.65 = 0.046 ohms

0.5 ohm readings -
ene Rb = (1.421-1.328)/2.26 = 0.041 ohms
KPC Rb = (1.390-1.264)/2.16 = 0.058 ohms


Coming back to voltage maintenance - 

2 ohm load at a current draw of about 0.66A
eneloop was 0.04V higher than the KPC or about 3% higher

0.5 ohm load at a current draw of about 2.2A
eneloop was 0.064V higher than the KPC or about 5% higher

I've probably had about 1/2 dozen cycles through both eneloop and Kodak P-C


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## Mr Happy (May 16, 2008)

Yes, I got the sign wrong in my formula of course. It should have been:

Internal resistance = (V1 - V2) / (I2 - I1)

The other thing I should mention is that it is important to take the two readings as close together as possible. In an ideal world it is done with two meters measuring amps and volts simultaneously. You momentarily connect and disconnect the second resistor to jump back and forth between high resistance and low resistance, to try to obtain readings that are repeatable and not drifting over time. Every time you measure the voltage on a NiMH after testing it will have moved a bit, and that movement will upset the accuracy of the result.

What you are trying to approximate is the slope of the line when you plot voltage and current on a graph. The slope of such a line (voltage/current) is the resistance.

The way I originally calculated it with open circuit voltage is just a special case of using two resistances, only we have one of the resistances (open circuit) being infinite giving a current of zero in that case. It gives you

Rb = (V1 - V2) / (I2 - I1) = (Vs - V) / (I - 0)

Incidentally, the higher voltage of the Eneloop with the 0.5 ohm load is starting to look quite apparent, I think.


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## UnknownVT (May 16, 2008)

Mr Happy said:


> The other thing I should mention is that it is important to take the two readings as close together as possible. In an ideal world it is done with two meters measuring amps and volts simultaneously. You momentarily connect and disconnect the second resistor to jump back and forth between high resistance and low resistance, to try to obtain readings that are repeatable and not drifting over time. Every time you measure the voltage on a NiMH after testing it will have moved a bit, and that movement will upset the accuracy of the result.


 
Yep, I noticed that - it's like trying to hit a moving target since I only have the one cheapo DMM - but I guess this is probably good enough just as an indication (close enough for jazz) ....

I looked up the formula you gave, and they had the sign wrong too 

The other calculations were -

0.5 and 2 ohm readings
ene Rb = (1.400-1.328)/(2.26-0.67) = 0.045 ohms
KPC Rb = (1.360-1.264)/(2.16-0.65) = 0.064 ohms

0.5 and 1 ohm readings
ene Rb = (1.388-1.328)/(2.26-1.25) = 0.059 ohms
KPC Rb = (1.336-1.264)/(2.16-1.22) = 0.077 ohms

It almost seems that internal resistance increases for increasing load (lower resistance/higher current)?



Mr Happy said:


> Incidentally, the higher voltage of the Eneloop with the 0.5 ohm load is starting to look quite apparent, I think.


 
The difference in voltage maintenance for the eneloop is greater/higher over the KPC as the load increases (lower resistance/higher current). 

Just to make this more obvious -

open-circuit - current draw of 0.00A 
eneloop was 0.029V higher than KPC or about 2% higher

2 ohm load at a current draw of about 0.66A
eneloop was 0.039V higher than KPC or about 3% higher

1 ohm load at a current draw of about 1.23A
eneloop was 0.052V higher than KPC or about 4% higher

0.5 ohm load at a current draw of about 2.2A
eneloop was 0.064V higher than KPC or about 5% higher


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## UnknownVT (May 16, 2008)

Mr Happy said:


> You could try the same thing with partially discharged cells for a comparison. You might see a greater relative voltage drop in that situation.


 
I partially discharged the same 2 batteries in the Dorcy 45lumen 1AA flashlights for about 25 minutes - probably to approx half capacity - ie: about 1/2 the runtime until the lights would not turn on again (see post #*11*). Allowed the batteries to rest/cool down for about 1.2 hours (as those lights run noticably warm - so the batteries were warm at end of discharge).

Readings -

Open-circuit (o-c) -
ene 1.298V; FA=10.4A; 1.293V
KPC 1.273V; FA=9.9A; 1.267V

2 ohm load -
ene 1.266V @ 0.60A
KPC 1.243V @ 0.59A

1 ohm -
ene 1.247V @ 1.17A
KPC 1.220V @ 1.14A

0.5 ohm -
ene 1.224V @ 2.09A
KPC 1.176V @ 2.01A

ending o-c -
ene 1.294V
KPC 1.267V

Internal resistance calcs -
1 & 2 ohm -
ene Rb= (1.266-1.247)/(1.17-0.60) = 0.033 ohms
KPC Rb= (1.243-1.220)/(1.14-0.59) = 0.042 ohms

0.5 & 2 ohms -
ene Rb= (1.266-1.224)/(2.09-0.60) = 0.028 ohms
KPC Rb= (1.243-1.176)/(2.01-0.59) = 0.047 ohms

0.5 & 1 ohm -
ene Rb= (1.247-1.224)/(2.09-1.17) = 0.025 ohm
KPC Rb= (1.220-1.176)/(2.01-1.14) = 0.051 ohm

the other way of calc using the o-c voltage (I used the ending o-c V)
2 ohms load -
ene Rb = (1.294-1.266)/0.60 = 0.047 ohms
KPC Rb = (1.267-1.243)/0.59 = 0.041 ohms

1 ohm -
ene Rb = (1.294-1.247)/1.17 = 0.040 ohms
KPC Rb = (1.267-1.220)/1.14 = 0.041 ohms

0.5 ohm
ene Rb = (1.294-1.224)/2.09 = 0.033 ohms
KPC Rb = (1.267-1.176)/2.01 = 0.045 ohms

Voltage maintenance -

o-c ene was 0.025, 0.026 & 0.027V higher than KPC ~ 2% higher
2 ohm ene 0.023V > KPC ~ 2%
1 ohm ene 0.027V > KPC ~ 2%
0.5 ohm ene 0.048V > KPC ~ 4%

In this round of using approx 1/2 discharged batteries -
although the eneloop still showed consistent higher voltage maintenance than the KPC - it was only about 2% higher for loads up to 1 ohm or about 1.2A current draw.
It was only using the 0.5 ohm load with current draw of about 2A that the eneloop once again pulled away from the KPC by almost 0.05V and about 4%.

It would seem from this limited testing that the higher voltage differential is more pronounced when the batteries were nearer full capacity and lessens with diminishing capacity - it remains that the eneloop hold voltage better than the KPC with higher loads (ie: lower resistance/higher currents)


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## UnknownVT (May 20, 2008)

Update - I used the Pentax K100D dSLR today with the same (continuing) set of Kodak Pre-Charged and took over 46 shots all with flash.

I saw half charge signal 11 shots in and it stayed there (except for an occassional bounce back to full) eventually I saw the low ("empty") battery icon (there is one more stage when that flashes - but that would be close to shutdown) about 38 shots in - however the batteries manage to keep going. 

The shot count on these Kodak Pre-Charged is now 540 - when I checked just before I started this post the indicator was back to full charge icon and remained that way even after two test shots no flash - but long exposures.

readings Kodak Pre-Charged
#5 1.264V; FA=9.4A; 1.260V } more recently
#6 1.265V; FA=9.6A; 1.262V } charged pair
#7 1.253V; FA=9.4A; 1.248V
#8 1.253V; FA=9.6A; 1.248V

Of course when I returned the set to the dSLR after the flash amps the indicator showed half-charge. 

Interrupting this post - I went and checked the indicator was back to full-charge - but a single test shot dropped it back to half charge again.

However a shot count of 540 is only 27 short of the eneloop total of 567 - this is a sterling performance for a battery that definitely has lower operating voltage and higher internal resistance than the eneloops.

The eneloop shot count of 567 was over a much longer period just short of 5 months - whereas the KPC is only over a period of 1- 1.5 months (but this is more typical of my usage - with the eneloops I had previously been charging up and using a set of regular NiMH on day of shoot and kept the eneloops as backup and standby in the dSLR). 

I used more flash with the eneloop set, and did more flash amp readings.

But I am now very impressed with these Kodak Pre-Charged.


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## UnknownVT (May 25, 2008)

Update - I used the Pentax K100D dSLR today with the same (continuing) Kodak Pre-Charged and managed another 126 shots (almost all without flash) until power-off .

So the accumulated grand total for this set of Kodak Pre-Charged is 671 shots - this exceeds the eneloop total by 104 shots.

But the conditions were different as outlined already in my previous post above.

However I would say these Kodak Pre-Charged are at least roughly equal to the performance of the eneloops I recounted previously.

Reading of the Kodak P-C after 4 hours rest -

#5 1.251V; FA=9.3A; 1.243V
#6 1.252V; FA=8.7A; 1.246V
#7 1.240V; FA=9.1A; 1.232V
#8 1.238V; FA=9.2A; 1.231V

With the 4 hour rest these probably would power up the dSLR and be able to take a few shots - but the state of these KPCs are about the same as the eneloops after power-off and 10 hours rest.

I had the impression that the dSLR signalled the low ("empty") battery icon for quite a while before the camera powered down - seemed longer than for the eneloops - perhaps this was another indication that the KPC voltage is lower/sags more under load than the eneloops - 
however we have already shown the higher voltage maintenance of the eneloops by using static 0.5, 1 and 2 ohm loads.

Anyway - I am now very pleased with the performance of these Kodak Pre-Charged - 671 shots on the Pentax dSLR exceeds even the spec'd shot count for Lithium AAs with_OUT_ flash of 660.


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## UnknownVT (May 28, 2008)

Summary - _Superceded - please see New Summary in Post #_*57*_ (link)_

_EDIT to ADD_ -
Important - please see Post #*56* - where I managed to finally show that the lower operating Voltage under load of the Kodak Pre-Charged causes my dSLR to shut Off even though there was still remaining charge to take many more photos.

This thread admittedly has been a hodge-podge of ad-hoc experimentation.

My initial objective was to try to show that eneloops maintained a higher operating voltage (under load) than the Kodak Pre-Charged - by demonstrating some difference in usage in voltage level sensitive devices.

Although I started this thread with what I thought was a pretty clear demonstration of the advantage of higher operating voltage under-load of the eneloop - subsequently after more (ad-hoc) experiments/test I was _NOT_ able to do this conclusively.

(1) I have demonstrated that the eneloops do maintain a higher operating voltage under load than the Kodak Pre-Charged by using static fixed resistors - 0.5, 1, 2 ohms (with current draws of about 2+A, 1.2A, 0.6A respectively) using fully charged and about 1/2 discharged batteries - Posts #*41*, #*44* , #*47* 

(2) Calculating the internal resistance of the batteries showed eneloops had lower internal resistance than Kodak P-C - Post links above, + Mr Happy's post #*42* 

(3) Use in flashlight with high voltage threshold cut-off - Dorcy 45 lumen 1AA - runtime with 4 min On and 1 min Off - attempting to show a difference when the light was turned back on (lower voltage may fail to turn light on) - showed that eneloop and Kodak P-C were basically neck and neck - if anything the Kodak P-C may have had more remaining charge/capacity than the eneloop Post #*11* - 
caveat - although these were two samples of the same flashlight - there might be some difference due to sample variation - so this may not be quite as conclusive - I may have to re-do the runtimes using just one flashlight.

(4) Use in well regulated flashlight Fenix L1D-Q5 (on High in general mode) - the straight runtime results were basically neck and neck post #*27* 

(5) (**see below addendum) Use in dSLR - Pentax K100D (notorious for being battery fussy) with relatively high voltage threshold cut-off. Much to my pleasent chagrin - the Kodak P-C seem to do as well as the eneloops in the one device where I thought higher voltage would really matter. The Kodak P-C actually well exceeded the shot count of the eneloop - but there were different conditions - however I would regard the performance of the Kodak P-C and eneloops as "sterling" - far surpassing specs and my expectations (especially considering the notoriety of the dSLR on batteries) Posts #*38* , #*49* .

Overall I am now very pleased with the performance of the Kodak Pre-Charged and would regard them basically "the same" as eneloops for most of my practical usage. 

But I still feel that eneloops are intrinsically "better" due to the higher operating voltage and lower internal resistance - but other than resistance testing - I have not been able to demonstrate any notable difference in any real practical usage - even when using devices that were known to be voltage level sensitive.

_EDIT to ADD_ **-
Important - please see Post #*56* - where I managed to finally show that the lower operating Voltage under load of the Kodak Pre-Charged causes my dSLR to shut Off even though there was still remaining charge to take many more photos. So point 5 above is _NO_ longer valid.......

eneloops _*are*_ better than the Kodak Pre-Charged in the Pentax K100D dSLR due to eneloop's higher operating voltage under load.....

_Note: this summary has been superceded - please see New Summary in Post #_*57*_ (link)_


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## Black Rose (May 28, 2008)

Nice work Vincent.

A lot of good data provided by all your various hands on tests.


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## UnknownVT (May 28, 2008)

Black Rose said:


> A lot of good data provided by all your various hands on tests.


 
Thank you Black Rose for being so kind and generous.

I felt this thread was not very well organized on my part - 
it almost felt like I was "making it up as I went along".

Because I ended up doing so many different types of "ad-hoc" experiments
- I thought a summary was needed 
- even if it was only to clarify things for myself


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## SilverFox (May 28, 2008)

Hello Vincent,

Don't worry... Testing is often like this. Sometimes you have to make it up as you go along. In the end, it often works out fine.

People often get better with practice, so what's your next project?  

Tom


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## UnknownVT (May 28, 2008)

SilverFox said:


> Don't worry... Testing is often like this. Sometimes you have to make it up as you go along. In the end, it often works out fine.
> People often get better with practice, so what's your next project?



Kind words indeed Tom - thank you.

Yeah coming from a science/engineering background I do understand that experiments are exactly that, and even a negative result is worthwhile.

But it's taken me several tries in this one to come to the eventual conclusion that probably most people would get intuitively without all this messing around -
that LSD batteries mostly perform about the same for most practical usage.

I failed to demonstrate that higher operating voltage (under load) of the eneloop showed any significant practical advantage over the Kodak P-C -
despite clearly showing that eneloop has higher operating voltage and lower internal resistance.

So for me eneloop and Kodak Pre-Charged perform about the same - 
even in devices that I thought were more critical about voltage levels.


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## UnknownVT (Aug 31, 2008)

Follow up -

It's taken me this long to deplete the set of eneloops in the Pentax K100D dSLR - the final shot total was 650 - this is similar to the outstanding result I last got on the Kodak Pre-Charged (671 shots). 

So as far as use in the Pentax K100D dSLR (battery fussy) is concerned my Kodak P-C and eneloops show very similar performance - they both exceed the Pentax K100D specified shot count for 2500mAh NiMH in fact do as well as the specs for lithium AA batteries.

This is outstanding - eneloops (do v well, as most would expect) and are matched easily by the Kodak Pre-Charged - for the time being a bargain of sort at $8.97/4 at WalMart (just noticed the increase in price from $8.47 to $8.97, which used to be the price of the RoV Hybrids at WalMart).

A point to note - the KP-C (last charged May/25/2008) I just put in the K100D, did show 1/2 charge indicator after trial shots - which then would recover to full charge - I think this is similar to what I first observed in my opening post. 
So it would appear that the K P-C may well have lower operating voltage which would cause the 1/2 charge indication - this time it's just over 3 months storage from last charge - I'll keep a note on how this set lasts (total shot count).


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## UnknownVT (Sep 1, 2008)

UnknownVT said:


> A point to note - the KP-C (last charged May/25/2008) I just put in the K100D, did show 1/2 charge indicator after trial shots - which then would recover to full charge - I think this is similar to what I first observed in my opening post.
> So it would appear that the K P-C may well have lower operating voltage which would cause the 1/2 charge indication - this time it's just over 3 months storage from last charge - I'll keep a note on how this set lasts (total shot count).


 
This is disappointing......

I used the Kodak Pre-Charged today in the Pentax K100D dSLR it showed 1/2 charge only after a few shots and continued in that state - then it started to show low charge -
and at shot count 177 the camera shut Off!! 
But simply turning the camera off and immediately back On - showed the 1/2 charge indication and the camera would continue to shoot, and would even occassionally show Full charge (very confusing).

Then after another 72 shots the camera shut Off again! 
- again merely turning it Off than On - seem to get the camera working without shut Offs for the rest of the shoot (another 18 shots).

So I think this is pretty conclusive for me - 
after just over 3 months' storage from last charge - these Kodak Pre-Charged started to show lower charge (just as described in the opening post) 
- and although they still "work" in the dSLR - the operating voltage would dip low enough to cause the camera to shut Off - only a momentary rest (in turning Off then On) was enough to have the batteries back to working again - which shows that there is still capacity 
- but the lower Voltage under load would cause the camera to shut Off. 

The shot count on this set of KP-C is now 265 do far - so there seems to be "good" capacity 
- but the lower Voltage under load caused the camera to shut Off twice so far.......

Even though it is inconvenient - I'll persist with this set of KP-C - just to see how many shots I can squeeze out of them until final shut Off (ie: turning Off and On will not resuscitate).

The main difference between this usage and the previous report of the KP-C - this time the batteries were charged just over 3 months ago - whereas previous report of 671 shots was with the batteries charged only 4 weeks before for one pair, and the other pair only about 1 week (see Post #*38* about 1/2 way down). The total duration of the previous shot count for the KP-C was just under 1 month (so the batteries were just under 2 months from charge for one pair and just over 1 month from charge for the other - so no where near the 3 months from charge for today's use, and 4 months from charge for the opening post.

It would seem that after a few months the KP-C drops in voltage level - more than eneloops. The 1st shot count for the eneloops of 567 shots at that point the eneloops were nearly 5 months from charge (see first part of Post #*38*) when I first started this thread those eneloops were already over 4 months from charge.....

However it's ironic this is bascially the conclusion I initially tried to postulated in my opening post #*1* 
- the lower operating Voltage (under load) of the Kodak Pre-Charge would cause premature low battery, or even shut down in the Pentax K100D dSLR 
- whereas the eneloop having better voltage maintenance under load should do better. 

This has now been shown to be the case.

eneloops _*are*_ better than the Kodak Pre-Charged in the Pentax K100D dSLR due to eneloop's higher operating voltage under load.....

- so I will do as I previously said - use eneloops in the Pentax K100D dSLR and keep the KP-C for other uses.


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## UnknownVT (Sep 2, 2008)

New Summary - superceding the one in Post #*50* above.

I was able to show using fixed resistors that eneloops maintain a higher operating voltage under load than the Kodak Pre-Charged.

eneloops also had a lower internal resistance than the KP-C - 
all these were good things.

In practical tests - 

1) I was unable to show advantage of these aspects when the respective batteries were recently charged in flashlights unregulated and current regulated.

2) When recently charged the Kodak Pre-Charged did as well, and better than the eneloops in the very battery fussy Pentax K100D dSLR.

3) _BUT_ - after storage of about 3 to 4 months from charge the Kodak Pre-Charged did show low battery signal and shut down the dSLR "prematurely" when there was obvious remaining charge - enough to continue shooting a significant number of shots 
- whereas the eneloop did _NOT_ suffer from this. 
This shows me that the high operating voltage under load maintained by eneloops makes them better suited than the Kodak Pre-Charged - which had otherwise matched the eneloops step-for-step when recently charged.

_Opinion_ - although one could just say the Kodak Pre-Charged lost more charge/capacity in the 3-4 months storage than eneloops - I don't _think_ it is loss of capacity - from the self-discharge tests I've read about KP-C - they seem to hold up well in comparison to eneloops, in one case showing more capacity throughout the 90 days.

So I _think_ the KP-Cs have _not_ actually lost more capacity - 
but just have lower voltage maintenance than the eneloops - 
causing the low battery signal and even shut down on the dSLR - 
the fact that the KP-C would work again with a mere momentary rest (turning dSLR off then on) shows there still is good remaining capacity - but the camera shows low battery and even shuts down.

Therefore - when recently charged the KP-C easily match eneloops - 
but after about 3 months from charge the eneloops clearly show an advantage of higher voltage maintenance - 
in voltage sensitive devices (eg: Pentax K100D dSLR) this makes a _real practical_ difference.


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## UnknownVT (Sep 6, 2008)

UnknownVT said:


> I _think_ the KP-Cs have _not_ actually lost more capacity -
> but just have lower voltage maintenance than the eneloops -
> causing the low battery signal and even shut down on the dSLR -
> the fact that the KP-C would work again with a mere momentary rest (turning dSLR off then on) shows there still is good remaining capacity - but the camera shows low battery and even shuts down.


 
_FWIW _- a follow up -

I still have the "disappointing" set of Kodak Pre-Charged in the Pentax K100D dSLR - and today I used it for a few trial shots to see if the KP-C's were still holding up.

First note was that on turning on the dSLR battery indicator showed full charge - and did so even after a few shots including flash.

Eventually showed 1/2 charge - but simply turning the dSLR off then On restored it to full-charge.

So I think this would appear to confirm the KP-C probably still have good amount of remaining charge - but may not be able to maintain high enough operating voltage under load - which then causes the low battery signal and even shut-down of the dSLR reported previously. 

Given rest the KP-C's restore their voltage level - but put them under load for significant amount of use - the KP-C's voltage will dip below the dSLR's operating voltage threshold to cause the shut-down.


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## geek4christ (Sep 7, 2008)

Hi Vincent,

I just wanted to chime in here and say I've really enjoyed this thread. When I get on my LSD soapbox with my friends and family, I can confidently recommend the Kodaks thanks to your fine work here.

I'm also the proud owner of a new K200D, a purchase I probably wouldn't have made without your verification that Eneloops feed the Pentax cameras quite well.


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## UnknownVT (Sep 7, 2008)

geek4christ said:


> I just wanted to chime in here and say I've really enjoyed this thread. When I get on my LSD soapbox with my friends and family, I can confidently recommend the Kodaks thanks to your fine work here.
> I'm also the proud owner of a new K200D, a purchase I probably wouldn't have made without your verification that Eneloops feed the Pentax cameras quite well.


 
Thank you so much for the kind feedback (I was wondering if anyone was still reading this thread ).

I'm embrassed to say that this thread bounced about all over the place.

I started by thinking I had found a way to show the advantage of the higher voltage maintenance of the eneloop over the KP-C (using the Pentax K100D dSLR) - but all of my subsequent tests failed to do that conclusively.

However storing a set of Kodak Pre-Charged for 3 months, managed (finally) to show the eneloop advantage - much to my own chagrin - just the way I tried to do initially .

With hindsight - I should have just tested that initial set of 4 months from charge KP-C in the K100D, and that should have shown the eneloop higher voltage maintenance advantage.

Hopefully with the K200D, Pentax may have improved the over-sensitivity of their (too high) battery threshold... nevertheless I would use eneloops. 

Enjoy your K200D - it's a fine choice.


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## UnknownVT (Sep 22, 2008)

UnknownVT said:


> Even though it is inconvenient - I'll persist with this set of KP-C - just to see how many shots I can squeeze out of them until final shut Off (ie: turning Off and On will not resuscitate).


 
Well impatience got the better of me.

I was using the dSLR today - for what I thought was non-demanding (ie: no flash and under normal bright conditions) and the camera shut-down on me in the middle of the session - so I won't persist further as it would be too just inconvenient - so have finally given up on this set of KP-C - final total shot count? just 347!!! - this is _WAY_ lower than the 671 shots I managed to get from the KP-C set - when they were more recently charged (however, to be fair, this is still "_repectable_" - easily within the specs of the K100D for regular 2500mAh NiMH)

This is relatively "disappointing" for me - as the KP-C do not match the eneloops, after more than about 3 months - 

However it is _NOT _actual loss of capacity from storage - but lower operating voltage under load - which is the very thing that gives the Pentax K100D dSLR its notorious reputation for being very battery fussy.

To prove this for myself I took two of the KP-C from the set and and used them on High (in general mode - not Turbo) in the same Fenix L1D-Q5 used in the crude runtime test previously in Post #*27* - they both managed just over about ~55 mins until very low/no light - compared to the ~125 mins when the KP-C was freshly charged - this shows the used KP-C still had quite substantial charge left in them - may be as much as 44% left - 
_IF_ the K100D had been able to utilize the remaining capacity - that probably would have resulted in a "_theoretical_" shot count closer to 631! - which is in the ballpark of the previous set of KP-C (when more recently charged) and the eneloops.

I know this seems to be beating a dead horse - but I can finally prove (to myself at least) that eneloops do maintain a higher operating voltage under load and do show a practical advantage when used in voltage level sensitive devices (like the Pentax K100D dSLR) - for me the eneloops have to be the choice for use in this camera - 

The Kodak Pre-Charged although do perform well, and managed to keep up with eneloops - will not do so after about 3 months storage - not that they lose capacity (they did _*not*_) but because they have lower operating voltage under load at that point...... 
ie: KP-C do not maintain their operating voltage under load as well as eneloops.


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## UnknownVT (Nov 22, 2008)

remember those eneloops that I charged back on April 27? (see post #*38* in this thread) 

I put them in the Pentax K100D dSLR on Sept/22 (see post #*61* ) - so almost 5 months after charge (although one of the eneloops was used for the internal resistance test so was recharged on May/16 - so over 4 months for just that one) and those managed 837 shots before giving up on Nov/20 - that's almost 7 months after charge (6 months for one). 

Most of the shots were without flash - but 837 is huge for the Pentax K100D - especially for batteries that were charged almost 5 months before then used for almost 2 months.

This performance is _WAY_ better than the Kodak Pre-Charged that I considered "disappointing" (post #*61* ) when used 3 months after charge managed only 347 shots with several shut-downs.

As reasoned previously it was not that the Kodak Pre-Charged had lost more charge than the eneloops - it is literally the eneloops were able to maintain higher operating voltage under the demanding load of the Pentax dSLR - whereas under the load the KP-C operating voltage would dip below the cut-off threshold of the dSLR - causing low battery signal and shut-down. 

(see post #*61* there was a lot of remaining charge in the KP-C which the dSLR was not able to utilize - the KP-C managed to power a Fenix L1D-Q5 on High for 55 mins = ~44% remaining charge)


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## UnknownVT (Dec 20, 2008)

In August I bought a set of DuraLoops (Duracell Pre-Charged LSD = confirmed re-bafged eneloops) - charged them up on 8/23/08.

Put them in the Pentax K100D dSLR on 11/20/08 - almost 3 months after charge.

I depleted them tonight to the point where the camera shutdown - 
so that's almost 4 months after charge .....

BUT the shot count was a whopping *1,169*!!! - some, but mostly without flash - but this count for me is bordering on the _unbelievably_ good.

Look back at Post #*35* where I show the shot count specs of the Pentax K100D for various battery types - the spec for 2500mAh NiMH was 430 shots no flash - DuraLoop = 1,169 = 272%!!

and the best figures were for lithium CR-V3 batteries at 730 shots, or lithium AA's at 660 shots without flash - 
here are the DuraLoops exceeded both those - achieving 1,169 shots with a few flash shots - 
that's some 60% better than spec for lithium CR-V3 
or 77% better than lithium AA's

I am most impressed with these DuraLoops (re-badged eneloop-R)


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## UnknownVT (Dec 20, 2008)

I just did this and thought it was worth posting here -

I speculate/suspect that Kodak Pre-Charged may be re-badged GP ReCyko? -

Here's an animated GIF comparing the discharge curves at various current rates for 3 LSD batteries (note these were produced by SilverFox in his threads - NiMh Battery Shoot Out and Eneloop Self Discharge study - CandlePowerForums )






I've also drawn a horizontal red line at approx 1.19V the cutoff threshold voltage for the Pentax K100D 
(Ref: Post #*49* (link) in thread - K100D - "Low-Battery" Problem gives details of the meter voltage levels)

One can see that there are more curves above the red line for the eneloop than the other two LSD batteries - 
although this may seem minor, I think this is very significant for the battery fussy/voltage sensitive K100D and *ist D family of Pentax dSLR.

So although I have Kodak Pre-Charged LSD (which are otherwise excellent - I suspect these are re-badged GP ReCyko) - I use eneloops and confirmed re-badged eneloops in my K100D over any other batteries.

To get over 1,100 shots out of a set of DuraLoops is simply incredible to me.


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## Black Rose (Dec 21, 2008)

These real world usage tests are great.

Keep up the good work Vincent.


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## UnknownVT (Dec 21, 2008)

Black Rose said:


> These real world usage tests are great.


 
You're very kind Black Rose....

Just slightly OT but still on voltage maintenance - as the Pentax dSLRs using AA batteries are very voltage sensitive - the relatively newly announced (now available as Quantaray - from Ritz and Wolf cameras) may be useful -

Nickel-Zinc (NiZn - Wikipedia)

CPF thread - Nickel-Zinc to hit the streets end of April

enGadget link , and the manufacturer - PowerGenix link

according to the NiZn AA pdf spec sheet - the nominal voltage is 1.65V.

This is good news as the discharge curve -




shows that the battery remains above 1.19V (Pentax dSLR cutoff threshold) for the tested currents up to 1C = 1.5A - until it's truly depleted - so it may be capable of delivering all of its rated capacity before the Pentax dSLR shuts down

The not quite as good news, is the capacity - typical 1500mAh with a minimum of 1350mAh (compared to 2000mAh typical and 1900mAh min for eneloops)





in a kind of mitigation - because it maintains higher voltage it appears that the batteries may be able to deliver its full capacity before Pentax dSLRs shuts down.

Some have said that the self-discharge rate is supposed to be about the same as typical (non LSD) NiMH.......

The other problem is that because of the higher nominal voltage chargers have to be different - one cannot use existing NiMH chargers.


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## UnknownVT (Jan 1, 2009)

For those who are still interested -
on Dec/19/08 I put a set of eneloops (charged on Aug/31/08) in my Pentax K100D dSLR - 
so that's ~3.6 months after charge.

I did not quite deplete them last night at a New Years Eve gig - 
although the dSLR was showing mostly low battery signal 
(but would also occassionally bounce back to half empty signal too) 
it never shutdown.

I changed them out between acts so that I would not have to worry about the camera shutting down 
(there is only so much I am willing to do.... or being bl**dy minded  )

However at the point when I swapped them out they had already taken 1,123 shots - a few flash shots - but mostly without flash - this is an amazing performance - considering the eneloops were charged some 3.6 months before and the Pentax K100D dSLR has been notorious for being battery/voltage sensitive - remember the Kodak Pre-Charged under similar conditions only managed 347 shots with several camera shutdowns....

So it looks like eneloops (and re-badges like DuraLoops) have "tamed" this notoriously battery/voltage fussy dSLR - over any other LSD battery.


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## Hitthespot (Jan 2, 2009)

Good stuff Vince. It would be interesting to throw a set of PowerEx LSD's in that camera just to see how they do compared to the Eneloops and rebadges.

Enjoyed this thread. Good work.

Bill


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## Anders (Jan 3, 2009)

Hello Vincent.

Thanks for all information in this thread.

It is very good to know everything you found here.

Anders


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## UnknownVT (Jan 3, 2009)

Hitthespot said:


> It would be interesting to throw a set of PowerEx LSD's in that camera just to see how they do compared to the Eneloops and rebadges.
> 
> Enjoyed this thread. Good work.
> 
> Bill


 


Anders said:


> Thanks for all information in this thread.
> 
> It is very good to know everything you found here.
> 
> Anders


 
Bill & Anders - thank you for your kind encouragement - 
I almost thought I was talking to myself - 
and feeling embarrassed for doing updates to this thread 

Bill -
I would try Imedion PowerEX LSDs in the Pentax K100D if I had any...
I already have more than I actually need in LSDs - and since the eneloops (and DuraLoops) have now solved my problems with the battery fussy camera ..... there is probably less incentive for me to get another brand.

Although I do acknowledge that the Imedions tested out well and seem to have more capacity than eneloops - but so did the Kodak Pre-Charged - but one can see after about 3 months' storage the voltage level maintenance made my dSLR shutdown prematurely, when there was still plenty of charge left in them


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## Hitthespot (Jan 3, 2009)

UnknownVT said:


> Although I do acknowledge that the Imedions tested out well and seem to have more capacity than eneloops - but so did the Kodak Pre-Charged - but one can see after about 3 months' storage the voltage level maintenance made my dSLR shutdown prematurely, when there was still plenty of charge left in them


 
Exactly what I was thinking. I was wondering about the storage factor and if the Imedions would have the voltage dip in the camera. It is amazing how the Eneloops just plain perform. Like you I have a number of Eneloops. I just bought the Maha C9000 Charger and my first 2 4packs of the PowerEX 2700 cells. I bought the cells because I figured I could use them in power hungry devices like my GPS and Fuji S6000fd digital camera. With the extra $ spent on the batteries I got free shipping. I'm just wondering if I shouldn't of went a head and bought the Imedions if they perform as good as the Eneloops.

Bill


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## PeAK (Feb 5, 2009)

*Re: eneloop vs. Kodak-> R_int Calculation*



UnknownVT said:


> .
> .
> .
> For example I report on voltages - but they are open-circuit readings which are obviously not as useful or meaningful as the actual operating voltage under load.
> ...



The discharge graph can be simplified to two numbers by using a vertical cutline of the graph taken at some point during the discharge curves. In this example, the output characteristic past the 1/2 way point was used: 








The slope of the line in the figure below is equal to the internal resistance "Ro" and the unloaded operating point by "Vo". Lower internal resistance will result in tighter spacing of the discharge curves for different current loads.




​ 
Batteries are very close to "ideal voltage sources" and can be represented by an equivalent circuit. The drop in output voltage (Vt) when loaded is determine by the "output series resistance" or "internal resistance" called * R_o *. You would a great electrical engineer gauged by your thought process. For people without access to anything more than a DMM, adding a low value load resistor (2 Watt rating for 1 ohm) to your toolbox would allow you to constuct a poor man's ZTS tester.

With just the unloaded voltage (*Vo*) and loaded voltages and knowledge of the load resistor value the "intenal resistance" can be estimated. The lower it is, the better. Once known, you can use it to predict the output voltage for different loads that draw more current (or less).

The series resistance is given by :
R_int= (Vo - Vload)/ I_load [Equation 1]​But I_load is known exactly due to the relationship between the "load resistor" value and loaded voltage:
I_load= Vt/R_load = Vload/R_load [Equation 2]​Combining Equation 1 and 2:
R_int = (Vo-V_load)/(I_load)
= (Vo-V_load)/(Vload/R_load)
= (Vo/Vload - 1) * R_load​Example the eneloop:

Rint=(1.440/1.388-1) * 1 ohm =0.037 ohms (correction pointed out by Cemoi)​PeAK


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## Cemoi (Feb 8, 2009)

*Re: eneloop vs. Kodak-> R_int Calculation*



PeAK said:


> R_int = (Vo-V_load)/(I_load)
> = (Vo-V_load)/(Vload/R_load)
> = (Vo/Vload - 1) * R_load​Example the eneloop:R_int=(1.440-1.388)* 1 ohm = 0.052 ohms​



Shouldn't the numerical example look like "(1.xxx/1.yyy - 1) * 1 =..."?

A voltage difference multiplied by a resistance is not a resistance.

On the other hand, I'm surprised at the value you get. I've tested several of my AA NiMH (including brand new Maha Powerex 2700), and found values in the 0.28 - 0.65 ohm range, i.e. about ten times your value.


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## PlayboyJoeShmoe (Feb 8, 2009)

*Re: eneloop vs. Kodak-> R_int Calculation*

Extremely interesting thread!

I mostly use LSD Nimh 2 at a time in my GPS. I started doing that when 2500mAh batteries charged Sunday night would not run the GPS a full day on Wednesday!

ANY of the LSD NimH I have including Eneloop, Hybrid, Hybrio and Kodak will in fact run the GPS all day at least a couple weeks after charging.

While thinking about this post I checked a bunch of my older cells like Duracell White Rechargeable Accu 2050 and Lenmar No-Mem Pro 2000 and found them all at 1.27V after 2 to 3 months.

I plan to charge up 4 of each and try them this week.

My other use is as flashlight batteries and again I haven't found any of the first four I mentioned lacking in any way.

That camera sounds like a picky b*tch!

Anyhow I have not seen Eneloops for sale since I found the 4 I have with a charger at Wallyworld. 

I do have access to Hybrid, Hybrio, Kodak and Duraloop. Of those four which ones should I concentrate on getting more of?


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## PeAK (Feb 8, 2009)

*Re: eneloop vs. Kodak-> R_int Calculation*



Cemoi said:


> Shouldn't the numerical example look like "(1.xxx/1.yyy - 1) * 1 =..."?
> 
> A voltage difference multiplied by a resistance is not a resistance.
> 
> On the other hand, I'm surprised at the value you get. I've tested several of my AA NiMH (including brand new Maha Powerex 2700), and found values in the 0.28 - 0.65 ohm range, i.e. about ten times your value.



You're absolutely correct about my typo. I'll go back and correct the post. I'm pretty shure about the numbers I came up with using a 2 ohm load. The best batteries were some older Energizers 1700mA-hr (0.04 ohms) which I heard were made for them by Sanyo in the early days of a brand name Alkaline battery manufacturer entering the rechargeable scene. Later day Energizer 2500 were much worse at 0.16 ohms.


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## PeAK (Feb 8, 2009)

*Re: eneloop vs. Kodak-> R_int Calculation*



PlayboyJoeShmoe said:


> Extremely interesting thread!
> .
> .
> .
> I do have access to Hybrid, Hybrio, Kodak and Duraloop. Of those four which ones should I concentrate on getting more of?



Hello PBJoe,
In another thread related to NiMh overcharging issues, I was led to the Saitek (aka CCrane) charger thread posted back about 5 years ago by you. 



​This seem to be the state of the art charger back then before Lacrosse and Maha got into the game with more modern packaging and better marketing. One on those posts had a link (from Mr Happy) that suggested a scheme (1994) proposed by an SGS application note that would use the change in the slope of the voltage curve was zero. Some refer to this as the inflection point or *second derivative voltage slope termination scheme*.

It would seem that in posts discussing the _CCrane Quickcharger_ (aka _Saitek SmartCharger_ or _RadioShack 23-410_) did not suffer overcharging issues due to the use of the the above scheme and lead to increases in the *internal resistance*.did not suffer from overcharge issues 

Are you still using that charger , and if so, are you still happy with it ? It might the one charger that will not cook the NiMh batteries due to the use of negative delta-V terminations. It seems as if the new LSD eneloops might heat up quite a bit using NDV.

PeAK


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## PlayboyJoeShmoe (Feb 8, 2009)

*Re: eneloop vs. Kodak-> R_int Calculation*

Yes, funny you should mention the C Crane.

It took it a pretty good while starting at 1.27V to hit bottom and start charging the Duracell ACCUs.

Just changed to the Lenmars now.1.24v on the way down.


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## UnknownVT (Feb 9, 2009)

*Re: eneloop vs. Kodak-> R_int Calculation*



PeAK said:


> The discharge graph can be simplified to two numbers by using a vertical cutline of the graph taken at some point during the discharge curves. In this example, the output characteristic past the 1/2 way point was used
> The slope of the line in the figure below is equal to the internal resistance "Ro" and the unloaded operating point by "Vo". Lower internal resistance will result in tighter spacing of the discharge curves for different current loads.
> Example the eneloop:
> 
> Rint=(1.440/1.388-1) * 1 ohm =0.037 ohms (correction pointed out by Cemoi)​PeAK


 
Thank you so much for responding to this thread PeAK.

I assume since you were responding to my post #*41* above that you saw the many calculations of internal resistance of both the eneloop and Kodak Pre-Charged in the immediately following posts started bt Mr Happt - Post #*42* - then followed by #*44* #*45* #*46* #*47* 

I got (with Mr Happy's help in the calculations, ene=eneloop; KPC=Kodak Pre-Charged) -

Using 1 ohm fixed resistor and the open-circuit voltage -
ene Rb = (1.294-1.247)/1.17 = 0.040 ohms
KPC Rb = (1.267-1.220)/1.14 = 0.041 ohms

and using readings from 0.5 & 2 ohms fixed resistors -
ene Rb= (1.266-1.224)/(2.09-0.60) = 0.028 ohms
KPC Rb= (1.243-1.176)/(2.01-0.59) = 0.047 ohms

We used -

Internal resistance = (V1 - V2) / (I2 - I1)

and for the special case of using a single resistor and the Open-Circuit voltage 

Rb = (V1 - V2) / (I2 - I1) = (Vs - V) / (I - 0)


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## UnknownVT (Feb 9, 2009)

*Re: eneloop vs. Kodak-> R_int Calculation*



PlayboyJoeShmoe said:


> I do have access to Hybrid, Hybrio, Kodak and Duraloop. Of those four which ones should I concentrate on getting more of?


 
For me - I have convinced myself that eneloops are superior for maintaining higher operating voltage under load than any other LSD or NiMH. This is from my own "testing" (flaws and all) and from my numerous reading about LSD batteries.

So, for now it is the eneloop, or any confirmed re-badged eneloop - 
like DuraLoop (must be made in Japan with white tops - Duracell Pre-Charged Rechargeables - Buyer Advisory ...) 
or perhaps the HybrioLoops (as described by Mr Happy in Uniross Hybrios are Eneloops...? - but beware of When is a Hybrio not a Hybrio?).

But since DuraLoops are now so prevalent - I tend to get those on sale.

But please remember mine is still a special case of a very battery fussy dSLR - 
as I have shown in flashlights - voltage maintanence does not seem to be a major issue, 
in fact the Kodak Pre-Charged seemed to outperform eneloops when recently charged - 
BUT I cannot say for sure if the voltage maintance would become an issue if stored beyond 3 months - 
reasoning - please see Post #*61* and #*62* above.


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## PeAK (Feb 9, 2009)

*Re: eneloop vs. Kodak-> R_int Calculation*



UnknownVT said:


> .
> .
> I assume since you...saw the many calculations of internal resistance of both the eneloop and Kodak Pre-Charged
> .
> ...


 Hi Vincent,
I saw the many numbers that you reported. The variation in the resistance reflects the fact that the "straight line"/linear equations used to describe the V-I characteristic (V-I, hereafter) do account for a curvature in characteristic with smaller loads and increasing currents. To back up a bit, a model needs only to be as accurate/complex to get the job done: In this case, we just want to roughly grade batteries unloaded and loaded. We also want to be able to distinguish differences between batteries with the same unloaded performance (open circuit voltage) but with different voltages when loaded. These *2 condition*s allow us to "pin" down the values of *2 variable*s (Vo and Rb) to describe this condition. If it sounds like algebra, IT IS.

Mathematical Notation is just a shortcut language to convey a trend in something that we observe. To make the connection stronger, it is sometimes simpler to initially forgo the math/numbers and look at the trend directly with the aid of a graph. A read battery would have the following characteristic:




​
The currents I1, I2 and I3 correpond to currents when R=2ohm, R=1ohm and R=0.5ohms are attached, respectively. Immediately we can that drawing a straight line between (I3,V3) and (I2,V2) combination generateds the steepest line (i.e. largers Rb value). Any other combination of points will have a lower value. Using Currents I1 and I3 will generate a smaller value of Rb that the previous case and helps explains some of the trends you saw in your data.

I like mesuring the point on the curve (Io,Vo)=(0,Vo) after measuring the output voltage loaded so that the battery is preconditioned a bit prior to making the open circuit voltage. It also minimizes time delays between measurements which can impart an error due to the internals of the battery settling out after generating output.






UnknownVT said:


> We used -
> 
> Internal resistance = (V1 - V2) / (I2 - I1)
> 
> ...



[/quote]

The form (V2-V1)/(I2-I1) give the slope, so since 
Rb=-slope, we get the equation that you have been using.

If you really want to capture the curvature, then you can use a quadratic equation that will fit a line through all the dots. A more complicated model V=*a * *i^2+*b* * i+*c*​but not so good at conveying the slope information.

Compare that to V = Vo - Rb * i
Using higher currents to determine Rb will result generally in larger values of Rb
and less optimistic values of "V" for higher resistance loads.It may seem obtuse for now but the best model is the simplest model that you can live with. A complicated model is only worth it if you can manage the complexity to gain more insight.

PeAK


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## UnknownVT (Feb 9, 2009)

*Re: eneloop vs. Kodak-> R_int Calculation*



PeAK said:


> The form (V2-V1)/(I2-I1) give the slope, so since
> Rb=-slope, we get the equation that you have been using.
> If you really want to capture the curvature, then you can use a quadratic equation that will fit a line through all the dots. A more complicated model
> V=*a * *i^2+*b* * i+*c*​Compare that to V = Vo - Rb * i
> Using higher currents to determine Rb will result generally in larger values of Rb


 
Thanks PeAK - we were basically using the same equation(s) I only listed them so that others can be sure what Mr Happy and I were calculating.

However I prefer the version without using the R(load) - as there is no way I can measure the resistance accurately - mine is only a cheapo DMM which seems to show 0.6ohms when the leads are shorted on the 200ohm scale (the lowest) - readings for both 1 ohm resistors show 1.6 ohms - so one could say they are 1 ohm allowing for the 0.6 ohm offset.... 
- but that is really crude. Also the package rating/specs are 1 ohm +/- 10% so strictly speaking the resistor(s) used could be 0.9 to 1.1ohm - too much margin of error to use in the calcuations - using actual measured voltages and current(s) drawn probably has a better resolution on that cheapo DMM - even then it was liken to hitting a moving target - I just took the "best" measurements I could - it would probably be slightly different on another day/hour.....

Nevertheless I ended up with 3 sets of results for 0.5, 1, 2 ohm loads plus the open-circuit (no load) voltage which allowed 6 calculations for the internal resistance - and the general trend, not surprisingly, was that the internal resistance increased with increasing current draw (decreasing resistance) 
this was enough to give reasonable "confidence" in the figures - 
although there were slight variences -
there did not seem to be anything that stuck out to show possible major errors.

The increments for the resistive load were 0.5,1, and 2 ohms so pretty close to approximate the "curve" and in the common/practical range for flashlight usage (ie: in the range of about 0.6 to 2.4 Amps)

So the calculated internal resistances probably are good enough for an indication for both eneloops and Kodak Pre-Charged. 
Not forgetting, of course, this is strictly limited to the samples of one of each of the batteries I used.


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## Mr Happy (Feb 9, 2009)

*Re: eneloop vs. Kodak-> R_int Calculation*



UnknownVT said:


> even then it was liken to hitting a moving target - I just took the "best" measurements I could - it would probably be slightly different on another day/hour


A way to deal with this is to alternate back and forth between the loaded and unloaded state about once a second or so until the readings stabilize.


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## UnknownVT (Feb 9, 2009)

*Re: eneloop vs. Kodak-> R_int Calculation*



Mr Happy said:


> A way to deal with this is to alternate back and forth between the loaded and unloaded state about once a second or so until the readings stabilize.


 
Thanks, yes, I waited until the readings seemed to stabilize - but I only have the one DMM which meant making and breaking the circuit each time I changed from voltage to current - so it was still pretty crude.

Like I said the resultant calculations seemed good enough as an indication
- considering all the limitations - especially the sample size....


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## PlayboyJoeShmoe (Feb 12, 2009)

*Re: eneloop vs. Kodak-> R_int Calculation*

One pair of Lenmar NoMEM Pro 2000mAh batteries failed miserably to run my GPS all day on monday.

Both pairs of Duracell Rechargeable ACCUs 2050mAh DID run the GPS just fine yesterday and today.

Both types are some of my earliest nimhs.

The Duracells may be the first of the Hybrid/Hybrio type batteries.

Shame I only have 4.

edit for INTERESTING fact: The Lenmars that died during the day on monday show 1.27 and 1.24. The Duracells that lasted until I shut the GPS down at home show 1.25ea for Wed and 1.23 and 1.24 for todays.

AHA! one of the monday lenmars has 3.5FA and the other 1.5. The Duracells are all over 4 except one almost 4.

That explains things nicely!


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## UnknownVT (Mar 10, 2009)

I depleted a set of eneloops (my #1-4) in the Pentax K100D dSLR - the camera shut down during a test shoot - by turning it off and back on, the eneloops managed to shoot some more - but after about twice - even turning off then on failed to power the dSLR - so I consider this as low as one could drain the eneloops for all practical purposes. The final shot count for this set was 989 mostly without flash.

Since I now have a Maha C-9000 charger I thought I'd see how much charge was left in these eneloops - discharge current set at 0.2C = 400mA

eneloops -
#1 151mAh 25mins
#2 151mAh 25mins
#3 151mAh 25mins
#4 159mAh 27mins

pretty consistent with only #4 showing very slightly higher.

That's about 8% remaining charge - if the dSLR could actually take the batteries down to 0.9V (which it doesn't).

So this is pretty good considering how notorious the Pentax K100D dSLR is for being battery fussy and requiring higher operating voltage under load - my estimate is the DSLR is utilizing just over 90% of the eneloop capacity.


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