[TimothyB]

After the pre-charged eneloops failed, I tried again after leaving a set to charge while I was at work.

This time, it powered on fine, auto battery mode, full green. Took about 70 photos, maybe 10 of with flash. Then I switched to video, did 2 minutes without SR, then 50 seconds with SR. Still green.

Costco had a good deal, the big bundle for eneloops for about $28, about $7 cheaper than Amazon. And they had a 12 pack of Energizer Ultimate Lithium for about $19 or so. Best Buy wanted the same price for just 8.

If it helps, the camera's serial starts with 346. I heard people complain about 343. Not that mine has acted perfect. I'll be taking it to an animation expo in LA tomorrow where I'll give the eneloops a work out.

---

Last edited by TimothyB; 11-19-2009 at 02:03 PM.

[pentaxpup]

My K-x arrived!!

After have read through all the battery issues, these are the things I did and the result:

My battery until the Eneloops come is a set of old Duracell NiMh 1800mAh freshly charged.

1. Before inserted the lens, I put in the batteries and turned it on.
Camera started and battery status is green.

2. After a few shots, some live view, and a short movie, I turned the camera off and then on.
Camera started and battery status is green.

3. Turned the camera off, took out the batteries and then reinserted.
Camera refused to turn on.

4. Took the batteries out and then reinserted.
Camera started but stated battery depleted then went dead.

5. Turned camera off, then on.
Camera started but red.

6. Turned Live View on then off.
Camera battery status is now green.

7. Turned camera off then on
Camera is still green.

8. Took battery out then reinserted.
Camera is still green.

I'm happy with it Now I'm not sure I even need the Eneloops

[rawr]

My K-x arrived!!

After have read through all the battery issues, these are the things I did and the result: ....

This seems to confirm that the camera has to do some tests and calculations before it can properly assess (a) battery type and (b) battery charge remaining.

I think the problem is that normally you can assess the charge left on a alkaline (and possibly a lithium) just by measuring it's current voltage, but the same rule doesn't apply to nimh's. With nimh's to calculate the remaining voltage the camera may need to run a little voltage and discharge test in order to come up with an assessment of battery type and a calculation of battery status. It would also need to then periodically rerun this test in order to keep the battery status up to date, and store in memory the details of the current battery so it knows it's discharge profile.

I guess though Pentax need the K-x to just turn on and work immediately with the batteries inserted into it, assuming they have a viable charge. It is not ideal that users should be exposed to all this.

[JasonA]

I got my Kx a couple of days ago. I bought some new Powerex 2700mah batteries from Newegg to go with it. Charged in my LaCrosse charger, if that makes any difference.

Took the lithiums out, put the Powerex in. Camera recognized them instantly, full charge. Took a bunch of photos, used Live View a lot. Took several videos, probably 10 minutes total. Still showing full charge. Took the batteries out and reinserted them. This time is showed half charge. Changed to LV and it went back to showing full charge.

Guess I've got nothing much to complain about yet.

[noou]

maybe i am the only unfortunate one, but after the initial excitement i found that my previously unrecognized brand new GP 2700mAh only lasted 50 shots with the manual lens trick
not happy

[Eruditass]

Yep, not too many people were excited about that trick.

We're all just waiting on Pentax now

[noou]

Yep, not too many people were excited about that trick.

We're all just waiting on Pentax now

yeah... let's hope!

anyway, i would strongly ask the owners of "working" K-x's if they could try their camera with other batteries, especially non-hybrid-eneloop-like.
I fear that many of them would find that they previously relied on a set of fortunate batteries, but the average battery would not work. This would relax me a little: a trouble shared is a trouble halved.

[wll]

).

Bottom line: I think most of the K-Xs do not experience battery problems, it's just a few vocal minority and some paranoia that's spreading around.. if anything, the battery detection mechanism couldsometimes causes anoyyances, but it's definitely not a deal-breaker, set correct battery type, turn off camera, wait 10 secs, turn it back on usually fixes the problem.

Paranoia ......... bull crap .... I love it when some guy tells me what is happening in my life.

wll

[OutOfFocus]

I rejuvenated a set of old Rayovac IC3 2000 mAh NiMH cells. Turn on: green. After LV: green.

These batteries used to be in good condition. I only stopped using them because none of my chargers understood the IC3 pressure switch, and would revert to "charge at high rate" every time the internal pressure reduced and the switch closed, and I didn't want to damage the batteries that way.

[OutOfFocus]

anyway, i would strongly ask the owners of "working" K-x's if they could try their camera with other batteries, especially non-hybrid-eneloop-like.
I fear that many of them would find that they previously relied on a set of fortunate batteries, but the average battery would not work. This would relax me a little: a trouble shared is a trouble halved.

Sorry to disappoint you, but I've tried many sets of batteries and could get them all to turn on the camera, and except for one old set which I'm still working on, I get an initial green battery indicator. The batteries I have successfully made to work include: Sanyo Eneloop (3 sets), Powerex Imedion (3 sets), old Sanyo 2700 mAh (barely), Duracell 2650 mAh, Powerex 2700 mAh, Rayovac IC3 2000 mAh, and Rayovac 1600 mAh.

Getting the older and less frequently used batteries to work required a little bit of rejuvenating effort that didn't seem unreasonable given the condition of the batteries and their intended use in a high-current device. These older batteries also didn't work as long as the newer ones, but that's also to be expected and I thought they all performed reasonably given their respective conditions.

Rejuvenation work included one or more of: terminal cleaning, deep discharge cycling, and forming charges.

Terminal cleaning: an invisible (to my eyes at least) layer of oxide on the battery terminals that adds resistance. Usual advice is to use a pencil eraser to scrub the terminals. It looks like alumin[i]um foil also works, but take care not to short the battery. (If you ever need to clean up rusty metal, rubbing it with damp Al. foil is a miracle cleaner. Try it. You'll be amazed.)

Deep discharge cycling: the crystals that form when you charge the battery will slowly convert into a hard to discharge form that lowers discharge voltages and capacities. Slow charging and leaving the battery charged (which you should) will encourage the formation of this kind of crystal. Fast charging (but not too fast to cause other problems) will minimize their growth. Deep, slow discharging will cause them to break up, thus improving discharge capacity and voltage. But since every charge-discharge cycle reduces total capacity a little, deep discharge cycles should be used sparingly. When required, I try to deep discharge after using the batteries heavily. Since, I can't wait ~20-27 hrs, I discharge at 200 or 300 mA (overnight), followed by another discharge at 100 mA, following by a stint in a homemade discharger: a battery holder connected to a 10 ohm 1/2 Watt resistor in series with a 1 amp rectifier. I discharge them until they drop below 1.0 volt.

Finally, new non-LSD batteries and old batteries that have lost all their charge may have a patchy internal distribution of electrolyte that increases their internal resistance and also prevents them from accepting a full charge. A forming charge is a charge rate of 0.1C (0.1 times the battery's capacity) for 16 hrs. The battery is supposed to be able to withstand this without damage (from a discharged state presumably).

[noou]

Sorry to disappoint you, but I've tried many sets of batteries and could get them all to turn on the camera, and except for one old set which I'm still working on, I get an initial green battery indicator. The batteries I have successfully made to work include: Sanyo Eneloop (3 sets), Powerex Imedion (3 sets), old Sanyo 2700 mAh (barely), Duracell 2650 mAh, Powerex 2700 mAh, Rayovac IC3 2000 mAh, and Rayovac 1600 mAh.

actually i'm very happy for you! ..and a little more worried about me...
it would be interesting to be able to test the very same batteries on both your and my K-x... i don't own any of the batteries you tested, and I guess you don't own the batteries I use (Uniross 2500mAh, GP 2700mah, Sony CycleEnergy 2500mAh, Panasonic 2600mAh).
I definitely have to try some hybrid cells...

Getting the older and less frequently used batteries to work required a little bit of rejuvenating effort that didn't seem unreasonable given the condition of the batteries and their intended use in a high-current device. These older batteries also didn't work as long as the newer ones, but that's also to be expected and I thought they all performed reasonably given their respective conditions.

Rejuvenation work included one or more of: terminal cleaning, deep discharge cycling, and forming charges.

Terminal cleaning: an invisible (to my eyes at least) layer of oxide on the battery terminals that adds resistance. Usual advice is to use a pencil eraser to scrub the terminals. It looks like alumin[i]um foil also works, but take care not to short the battery. (If you ever need to clean up rusty metal, rubbing it with damp Al. foil is a miracle cleaner. Try it. You'll be amazed.)

Deep discharge cycling: the crystals that form when you charge the battery will slowly convert into a hard to discharge form that lowers discharge voltages and capacities. Slow charging and leaving the battery charged (which you should) will encourage the formation of this kind of crystal. Fast charging (but not too fast to cause other problems) will minimize their growth. Deep, slow discharging will cause them to break up, thus improving discharge capacity and voltage. But since every charge-discharge cycle reduces total capacity a little, deep discharge cycles should be used sparingly. When required, I try to deep discharge after using the batteries heavily. Since, I can't wait ~20-27 hrs, I discharge at 200 or 300 mA (overnight), followed by another discharge at 100 mA, following by a stint in a homemade discharger: a battery holder connected to a 10 ohm 1/2 Watt resistor in series with a 1 amp rectifier. I discharge them until they drop below 1.0 volt.

Finally, new non-LSD batteries and old batteries that have lost all their charge may have a patchy internal distribution of electrolyte that increases their internal resistance and also prevents them from accepting a full charge. A forming charge is a charge rate of 0.1C (0.1 times the battery's capacity) for 16 hrs. The battery is supposed to be able to withstand this without damage (from a discharged state presumably).

i really appreciate your advices/instructions, and i'm also a very techy person, but i think that we K-x users should not be forced to follow such complex procedures: we should be able to play with our toy already with the first decent set of batteries we can find...

btw, which charger would you recommend? the ubiquitous BC-900?

[rawr]

Just FYI.

There is an interesting thread in the Camera and Studio Accessories forum alerting people to some cases where using NiZn AA's has burnt out some people's Pentax AF360 flash guns, due to their higher voltage not being compatible with the charging circuit.

https://www.pentaxforums.com/forums/camera-studio-accessories/80786-nizn-batt...fgz-flash.html

Users of the NiZn's in the K-x may like to take note.

[OutOfFocus]

I definitely have to try some hybrid cells...

Definitely. Eneloops are your best bet.

i really appreciate your advices/instructions, and i'm also a very techy person, but i think that we K-x users should not be forced to follow such complex procedures: we should be able to play with our toy already with the first decent set of batteries we can find...

I agree. There are definitely bugs in the battery detection and charge reporting system that need fixing. Also, it's wrong for the camera to require batteries capable of supporting LV/Video when all you want to do is take a photo. It's a camera first! I was showing my camera to a P&S user, and she ooh'ed and aah'ed about it having a viewfinder. I really like Eruditass's suggestion for a LV/Video disabled mode once the battery is too low to support them (instead of turning the whole camera off).

btw, which charger would you recommend? the ubiquitous BC-900?

I don't have that one, but it seems like a fine and capable charger. I have a Maha MH-C9000, which is also a fine and capable charger, and I like it. In fact, I just bought one (and 8 eneloops to go with it) for my son when he started college this year.

[Conan]

Just FYI.

There is an interesting thread in the Camera and Studio Accessories forum alerting people to some cases where using NiZn AA's has burnt out some people's Pentax AF360 flash guns, due to their higher voltage not being compatible with the charging circuit.

https://www.pentaxforums.com/forums/camera-studio-accessories/80786-nizn-batt...fgz-flash.html

Users of the NiZn's in the K-x may like to take note.

NiZn is working fine in my K200D!

[OutOfFocus]

I filled my K-x with some fully charged Rayovac IC3 2000 mAh non-LSD batteries. Initially they indicated green, but after a short while (too short) they indicated orange. I took them out and measured their voltages under various loads as reported in the table below. To conserve space, I report the average voltage across the 4 cells. The maximum difference between the cells was 34 mV under the highest load. The voltages are measured. The currents are calculated using I=V/R.

Code:

Ohms  Volts  Amps
Open   1.45   N/A
3.3    1.40   0.42
0.77   1.27   1.6
0.43   1.17   2.7

They look like mighty fine voltages to me. The K-x is being mighty fussy to call them orange.