[kacansas03]

In the last 2 months I have bought 2450 Energizer NiMH AA's And the slow charger(takes 12-18 hours usually) and I am having wonderful luck with them. I had read where they loose charge quickly when stored but so far no problem. I don't know exactly how many shots I am getting on a set but I have only changed them once and have added a little over a thousand shots to the cameras counter. I use 2 and 4 gig cards recording in RAW. I do not generally fill the cards because I have learned to check the shots on the screen and do a lot of deleting that way. My wife uses these also in battery devices she has and no problems even when they are driving a motor.

[UnknownVT]

My K100D worked fine for more than a year. I could take some hundred shots on one charge. Now I'm lucky to get 20 off freshly charged set or I may even get "battery depleted" message with batteries right from the charger. I think my LA Crosse BC700 charger is to blame cause the problem started approximately when my old cheap charger broke... I think that La Crosse charges Ni-MH batteries higher than 1.2V and it makes the camera "think" that I have depleted alkaline instead of overcharged NiMH but I have no scientific data to prove it. I can discharge the batteries in the charger and it shows that they have about 2200 - 2500mAh capacity ... Oh, and i forgot to mention that alkaline work ok.

That sounds more like the rechargeable NiMH are going bad - either losing capacity or unable to hold a charge - net result is very few shots -
sometimes it can be just one battery in the set that's going bad.
(High capacity NiMH batteries often lose capacity and/or develop high self-discharge after some use).

Another very important aspect is operating voltage maintanence under load.
Pentax dSLRs are renowned to be very battery fussy and have a relatively high cutoff threshold voltage - higher operating voltage maintanence under-load is important - that's why so many people here seem to always recommend eneloops for rechargeables.

Please take a look at this thread - K200D Battery Meter Problem there's a lot of good information there, including why eneloops will perform better in the Kx00D (I know it's the K200D - but Pentax dSLRs share a lot of common traits when it comes to AA batteries)

[pentaxmz]

Batteries get old and tired with use although just a year's worth of use sounds somewhat quick. I switched to one-time use Lithium batteries for my *istD to circumvent the issue.

Did you know that rechargable CR-V3 Li-Ion batteries are now available? Now you can save some money and a tree!

Check out this site (but there may be other sources):
CRV3 Rechargeable Batteries and Chargers RCR-V3 RCRV3 Li-ion Lithium rechargeable Batteries MobyPower, Delkin, Lenmar

[Raybo]

Buy a few sets of hybrid batteries and a GOOD charger, I recommend this one.....

MAHA MH-C801D 8-Cell Battery Charger LCD $68.97 Special

[kacansas03]

Buy a few sets of hybrid batteries and a GOOD charger, I recommend this one.....

MAHA MH-C801D 8-Cell Battery Charger LCD $68.97 Special

THat may be a quality charger. I checked the manufacturers web site and found they have another charge that is even better at maintaining AA batteries. One thing you do not want to do is "fast charge" these batteries. A one hour charge will not get them to full charge, secondly you will really heat the batteries which shortens their life a lot, lastly they are not disclosing voltage and amperage that are applied to the batteries which can also result in incomplete charge and shortened life. On the same issue the product is made in Taiwan which gives me hope it is a quality product, secondly the other product I found which cost more addresses all these questions I mentioned above plus it has a battery reconditioning system that reads like it is the correct method. That one is the MH-C800S and does AA or AAA batteries but they have an even better unit the MH-C801D which can handle the other sizes but all their chargers do Only NiMH or NiCD batteries. No CR-V3 LI-ion batteries in these chargers. The rechargeable LI-Ion batteries are the best but do have to be disposed of correctly when they reach the end of their life. Lithium is dangerous stuff but so are the other batteries like the old NI-CAD's.

[rfortson]

Did you know that rechargable CR-V3 Li-Ion batteries are now available? Now you can save some money and a tree!

Check out this site (but there may be other sources):
CRV3 Rechargeable Batteries and Chargers RCR-V3 RCRV3 Li-ion Lithium rechargeable Batteries MobyPower, Delkin, Lenmar

Rechargeable CRV-3's have been out for a while, but make sure you get regulated ones. I've read a few stories of the unregulated ones frying the camera. I've also read many success stories of people using the regulated ones. By the time I got ready to use them, though, I'd moved on to the K10D and K20D.

I'll second the recommendation for Thomas Distributing as well. They are a great source for all your power needs.

[kacansas03]

Rechargeable CRV-3's have been out for a while, but make sure you get regulated ones. I've read a few stories of the unregulated ones frying the camera. I've also read many success stories of people using the regulated ones. By the time I got ready to use them, though, I'd moved on to the K10D and K20D.

I'll second the recommendation for Thomas Distributing as well. They are a great source for all your power needs.

Just look on Google or Wikipedia for info on the CR-V3 battery and the rechargeable ones. Rechargeable types can reach 3.7V OR Higher which could result , in a bad situation, having an 8 volt or more battery power seen by the camera when you turn it on instead of the required 6V and the average high level of 7V. So I agree that one must make sure you are buying the correct rechargeable batttery.

[Bill Stickers]

I had this problem too. the problem is with the battery contacts on the camera. overtime the build up a layer of corrosion that interferes with the camera getting the voltage it needs.

Use an eraser to get it off. You'll know that it worked/this is the problem if the contacts look significantly cleaner/shinier after you clean them

[Fnarf]

I'm back from a trip, where I was able to test some batteries.

The Eneloops performed amazingly well! I couldn't believe it -- I was shooting continuously (aside from auto-power-down) for FIVE DAYS before the first set gave up the ghost. That was more than 800 pictures, not much flash but lots and lots of autofocus seeking. The second set is still in the camera, still going strong -- and I have plenty of spares now. I never got results like this from NiMh before.

The real test comes when I use them after not touching them for a month or two.

I think my problem with the other rechargeables was the charger, not the batteries. I threw away my crappy Lenmar charger, and got one of the conditioning chargers from Maha (the one recommended here), and both my old batteries and newish ones are showing much stronger condition now. I haven't tested them all completely (I'd have to sit and fire my camera several thousand times, which is boring).

I also got some Lithium-Ion rechargeables, also as recommended here. I haven't tried them yet.

Does anyone know if it's safe or advisable to charge Eneloops in the Maha conditioning charger, or should I stick to the one that came with? And vice-versa?

I kinda miss the old days, when a AA was a AA was a AA....

[UnknownVT]

The Eneloops performed amazingly well! I couldn't believe it -- I was shooting continuously (aside from auto-power-down) for FIVE DAYS before the first set gave up the ghost. That was more than 800 pictures
The real test comes when I use them after not touching them for a month or two.
I also got some Lithium-Ion rechargeables, also as recommended here. I haven't tried them yet.
Does anyone know if it's safe or advisable to charge Eneloops in the Maha conditioning charger, or should I stick to the one that came with? And vice-versa?

Glad to hear eneloops are doing well for you.

eneloops can be charged with any NiMH charger.

Obviously some NiMH chargers are better than others -
Maha does make some very good NiMH chargers -
the usual recommended "favorite" is the Maha C-9000.

As for rechargeable Li-Ion CR-V3 -
please make sure you have the 3V "regulated" versions.
The natural/native voltage of Li-Ion is 3.7V (fresh off the charger can be as high as 4.2V) -
so 2 in series would be 7.4V - 8.4V -
that's enough to FRY the K100D electronics

[Class A]

I kinda miss the old days, when a AA was a AA was a AA....

You mean the old days when you didn't have the fantastic Eneloops to rave about?

eneloops can be charged with any NiMH charger.

AFAIK, it shouldn't be a "rapid" charger though that charges in insanely short amounts of time (<30 min.). I believe "fast" chargers should be OK. IIRC, Eneloops will be fine with charging times no less then 2.5 hours. Anything below that may not be optimal for them but it would be good if an expert could clarify.

[Raybo]

I'm back from a trip, where I was able to test some batteries.

The Eneloops performed amazingly well! I couldn't believe it -- I was shooting continuously (aside from auto-power-down) for FIVE DAYS before the first set gave up the ghost. That was more than 800 pictures, not much flash but lots and lots of autofocus seeking. The second set is still in the camera, still going strong -- and I have plenty of spares now. I never got results like this from NiMh before.

The real test comes when I use them after not touching them for a month or two.

I think my problem with the other rechargeables was the charger, not the batteries. I threw away my crappy Lenmar charger, and got one of the conditioning chargers from Maha (the one recommended here), and both my old batteries and newish ones are showing much stronger condition now. I haven't tested them all completely (I'd have to sit and fire my camera several thousand times, which is boring).

I also got some Lithium-Ion rechargeables, also as recommended here. I haven't tried them yet.

Does anyone know if it's safe or advisable to charge Eneloops in the Maha conditioning charger, or should I stick to the one that came with? And vice-versa?

I kinda miss the old days, when a AA was a AA was a AA....

Yes it's safe!

Stick with the quality charger, it will make a world of difference in cell life and run time.

Ray

[Raybo]

BTW, you should condition your cells every 10-15 charging cycles.

I sware by the hybrid cells and a good charger, they blow away my run of the mill NIMH cells.

[UnknownVT]

AFAIK, it shouldn't be a "rapid" charger though that charges in insanely short amounts of time (<30 min.). I believe "fast" chargers should be OK. IIRC, Eneloops will be fine with charging times no less then 2.5 hours. Anything below that may not be optimal for them

The optimal charge rate for any NiMH (including eneloops) - is 0.5 - 1C.

Since AA eneloop capacity is 2000mAh (1900mAh minimum) -
that is between 1- 1.9Amps (1,000-1,900mA)
so batteries are charged in about 1 to 2 hours.

Reason: end of charge -dV is more easily detected with 0.5-1C charge rates, below about 0.3C it is almost impossible to detect the -dV end of charge.

a good source Battery University -

" Charging nickel-metal-hydride

Nickel-metal-hydride chargers require more complex electronics than nickel-cadmium systems. To begin with, nickel-metal-hydride produces a very small voltage drop at full charge and the NDV is almost non-existent at charge rates below 0.5C and elevated temperatures. Aging and degenerating cell match diminish the already minute voltage delta further. This makes full charge detection difficult.

A nickel-metal-hydride charger must respond to a voltage drop of 8-16mV per cell. Making the charger too sensitive may terminate the fast charge halfway through the charge due to voltage fluctuations and electrical noise. Most of today's nickel-metal-hydride chargers use a combination of NDV, rate-of-temperature-increase (dT/dt), temperature sensing and timeout timers. The charger utilizes whatever comes first to terminate the fast-charge.

Nickel-metal-hydride should be rapid charged rather than slow charged. Because of poor overcharge absorption, the trickle charge must be lower than that of nickel-cadmium and is usually around 0.05C. This explains why the original nickel-cadmium charger cannot be used nickel-metal-hydride.

It is difficult, if not impossible, to slow-charge a nickel-metal-hydride. At a C?rate of 0.1-0.3C, the voltage and temperature profiles fail to exhibit defined characteristics to measure the full charge state accurately and the charger must rely on a timer. Harmful overcharge can occur if a partially or fully charged battery is charged with a fixed timer. The same occurs if the battery has aged and can only hold 50 instead of 100% charge. Overcharge could occur even though the battery feels cool to the touch. "

I agree that those 15-30 minute chargers are bad news for any NiMH.

[Raybo]

When charging at higher current, the charge completeness reduces thereby lowering the charging capacity. This is to prevent battery overheating. This typically occurs at a rate greater than 1500mA. Generally speaking, 1000mA achieves nearly full charge completeness for AA batteries.