eneloop vs. Kodak Pre-Charged Voltage Maintenance

[Mr Happy]

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.)

 

[UnknownVT]

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?

 

[Mr Happy]

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.

 

[UnknownVT]

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 UNsuitably 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........

 

[Mr Happy]

#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.

 

[UnknownVT]

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.

 

[UnknownVT]

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.

 

[Power Me Up]

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.

 

[Mr Happy]

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.

 

[Mr Happy]

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.

 

[Power Me Up]

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...

 

[UnknownVT]

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

 

[Kankujoe]

Interesting thread!

Thanks for posting the results and procedures.

 

[UnknownVT]

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.

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?

 

[UnknownVT]

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 UNbelievably - 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..........

 

[Mr Happy]

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

 

[UnknownVT]

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

 

[UnknownVT]

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 OUTstanding 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.

 

[UnknownVT]

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.

FWIW I used the Pentax dSLR yesterday and took 203 shots - although mostly withOUT 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.

 

[UnknownVT]

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.