Sunday, July 26, 2009

K-m Battery Issue, Solution and Timing Measurbations

As for years, the AA battery issue of the Pentax DSLRs have not yet been completely resolved by Pentax, never (and forever - my bet).

There is no exception for the K-m, which now even only allows solely the use of AA type batteries and CR-V3 type cannot be inserted for what the battery compartment is designed, mechanically, since the K200D. Here is a shot about how the battery compartment is designed and made (note the protruding part inside):-



The problems of using AA NiMHs are heavy (about 110g for 4), short battery life, unstable battery power and lower camera performance.

I use Sanyo Eneloop and the battery half-depleted warning often appear after heavier power demand when using the camera. I really don't like it, or just hate it. And, four AA NiMHs which are roughly equal 110g, which are no good to carry around everywhere. For just the weight of such low performance batteries, I think it is not worth, in any sense.

But then here comes the Energizer Lithium AAs, which are bundled with the camera and is highly recommended by Pentax. Yes, they are light-weight and of high performance. But the main problem is that they are NOT Rechargeables! Cost is a concern here and more a problem for its non-environmental friendliness! Hey, men, please save the Earth!

So, can we all Pentax AA DSLR users can get the best of both worlds? I am afraid that the answer is No and Not, especially with the current line of Pentax AA battery DSLRs which do not even allow the use of CR-V3 so that even those *Regulated* CR-V3 cannot be inserted and used in any K-m and K200D.

Since I have two Regulated Rechargeable CR-V3 and a dedicated charger left from my old K100D (which can use the CR-V3 batteries), I have been thinking about to hack the batteries so that I could use the high performance Lithium-ion battery in my K-m again. But since Pentax have prohibited the use of even disposable CR-V3s for my K-m, I have been careful to think about it more and measured the battery voltage (again) for different battery types:-

- Eneloop: Maximum no-load freshly charged voltage for two: 2.5~2.6V;
- CR-V3: Maximum no-load voltage per each new battery: 3.3~3.4V;
- Energizer AA Lithium: Maximum no-load voltage for two: 3.1~3.2V;
- My Regulated RCR-V3 when freshly charged, no-load: 3.4V

Since it is just too difficult and actually non-sense to hack the K-m's battery compartment, I simply dissembled my CR-V3 and remove the part that has conflicts with the "prohibiter" of the battery compartment and re-wrapped the battery and sealed all the electrical parts with Denka Vini-Tape:-



Well, do note the above that the battery has PCB and circuitry and components inside in order to regulate the voltage down to 3.4V which is lower than the nominal voltage of 3.7 to 4.0V of the rechargeable Lithium-ion cells that are used.

But since two RCR-V3s now make up 6.8V and even disposable CR-V3s which can also have that maximum total voltage (of 6.8V also) are not "designed" to be used in the K-m, I have not been dare to insert two RCR-V3s in my K-m at the same time, as the overall voltage would be too high for the camera (The highest safe voltage limit would be 6.4V, i.e., the voltage of two new AA Lithiums). I opted not to take the risk to "overclock" my camera by that 0.4V, which maybe outside the design tolerance.

So, must I use the low voltage and low performance NiMHs in my K-m if I want rechargeables? In fact, my K-m will get the battery half-depleted warning shown for a set of four newly charged Eneloops after 100 shots and especially after high current/power is required/demanded, e.g., more AF, more LCD displaying, continuous shooting (this mode is really power hungry! Try it yourself!).

To get the best of both worlds and still make it safe enough, I mix one hacked RCR-V3 of mine and two Eneloops, so as to make up a "new" voltage of 6.0V, which is actually the idealistic value for battery voltage for all Pentax AA DSLRs! Mixing these two types batteries will not harm as:-

1. The batteries are in series but not in parallel;
2. The lower performance batteries are also rechargeables so there is no risk in being charging them up by another more powerful power source;
3. The higher internal resistance of any battery cell will limit the maximum current through the whole electrical circuit (but possibly the camera itself should be the bottle neck).

After all these hacking and voltage measurements, I still have to test the differences in performance for using different battery types and combinations, namely, I have measurebated the AF motor speed and the camera system/shutter time lag, here are the results:-

Batteries and Combination
Made-up total battery voltage (no-load)
AF Speed (See Remark 1)
Shutter Lag (See Remark 2)
4 Eneloops
5.2V
1.195s (Download sound file)
121ms (Download sound file)
2 Eneloops + 1 RCR-V3
6.0V
1.105s (Download sound file)116ms (Download sound file)
1 RCR-V3 + 2 AA Lithiums
6.6V
1.082s (Download sound file)112ms (Download sound file)
4 AA Lithiums
6.4V
1.088s (Download sound file)113ms (Download sound file)

Remarks:
1. The FA 43 Limited was mounted, first driven to infinity before the test, then pointed the camera to a bright sky without any pattern and let the motor ran from 00 to the nearest distance and back to 00 and the timing was measured;

2. Measured from the completion of shutter release button pressing to the time of exposure.

3. The above test was carried out in an air-conditioned room at around 24 deg. C.


Do note that the above test is carried out for freshly charged batteries and new AA lithiums from newly opened pack. The difference in performance will become more obviously shortly when the performance (actually on-load voltage) of the AA NiMHs (Eneloops - the best and most "suitable" model, already) drops very quickly after 100 shots or so and in heavier current/power demand situations.

In the meantime, I shall choose the 1 RCR-V3 + 2 Eneloop mixed rechargeable solution. Now, I have turned on the back (status) LCD of my K-m on all the time (via a Custom Function, which is actually the default setting, but power consuming) and need not to worry about battery power drainage any more.

Also, as you can see, the performance of the camera, when using the mixed rechargeable solution, is actually close to that of using solely new AA Lithiums, which is yet a good thing. It can also be noted that further increasing the battery voltage has only minimal benefit for the camera performances, for both AF speed and system/shutter time lag. So, the bottle neck and threshold is really the NiMH battery and most benefits can be obtained/seen when changed to AA Lithium (and now by only one Regulated Rechargeable CR-V3) - project completed, hacking completed! ;=D (Victory!)

p.s. IF I was the Engineer of Pentax, I would choose to use an proprietary Lithium-ion/Lithium Ploymer rechargeable solution in ALL the DSLRs - problem totally resolved and the end of the story and all problems!

26 Comments:

netrex said...

How many shots can you get with 4xAA with 2500 or 2700 mAh?

Test blog said...

Cool DIY action RH :)

Something is not clear to me. Did you actually test the number of shots available per charge?

I wouldn't be too alarmed by the battery meter on the camera. It is known that Eneloop voltage changes differently from normal NiMH batteries as it gets depleted, so that many electronic devices with a simple battery meter warn prematurely that Eneloops are getting depleted (they are calibrated with normal NiMH in mind).
Also, Eneloops are not the "best" batteries available in terms of sheer capacity (They are about 2100mAh, no?). Their advantage is that they keep their charge for months without self-discharging.

I think a more meaningful test should be to simply use the camera intensively with Eneloop, normal NiMH 2700mAh, and the other types you have, until they get depleted, and see how many shots they provided. Do it many times and then we'll have meaningful and useful statistics about K-m's battery usage.

The nice thing about it is that this way you can actually combine photography with measurebation! It could be fun! ;-)

Noam

Manu said...

The real issue is the accuracy of the battery meter. It's simply not good and it's normal: there is no real way to detect the remaining capacity. All you can test is the voltage.

I get the same problem as you have on the K-7 (battery grip stuffed with Eneloop) after power hungry operations like a burst or using liveview/video recording, the indicator will often lose 1 or 2 bars. But the curious thing is that if I go to the menu to choose the battery and don't do anything but just display the menu, the battery indicator get back the bars it just lost(!).

The normal NiMh 2700mAh are just garbage IMHO, the Eneloop while being only 2000-2100 work better, longer and don't lose their voltage as fast.

I wouldn't use CRV on the K-m. If Pentax removed that option there must be a reason, no?

On the K-m I use exclusively the Eneloops and I've been very pleased by the longevity and performance. The fact the K-m use AAs is a strong point for me, I'm not against Li-On proprietary batteries but they have their disadvantages too:
- Another one more charger (you can have your walls filled with chargers as you have a cell phone, an iPod, a camera, etc...
- A backup battery is costly
- difficult to find while travelling
- How to find them in 10 years after the manufacturer stopped producing them?

RiceHigh said...

> netrex said...
> How many shots can you get with 4xAA with 2500 or 2700 mAh?

I gave up to use those "2500/2700" mAh NiMH on Pentax DSLRs long ago as their charge just lose too fast for them to be usable. Normally, the user should charge the batteries and use them within a few days. Even worse, the voltage is also dropping too far for the Pentax DSLRs to tolerate.

RiceHigh said...

> Noam said...
> Did you actually test the number of shots available per charge?

Not yet. I've shot with my K-m for less than 400 so far (but it already kills one of my half-used pack of Energizer AA Lithiums). As for the Eneloops, they get the camera to show the half-battery warning just after 100 shots or something and the AF motor moves damn slow when the warning shows up!

> I wouldn't be too alarmed by the battery meter on the camera.

Not really.

> It is known that Eneloop voltage changes differently from normal NiMH batteries as it gets depleted, so that many electronic devices with a simple battery meter warn prematurely that Eneloops are getting depleted (they are calibrated with normal NiMH in mind).

Eneloop has flatter discharge curve than most other NiMHs and thus it can deliver more energy before the cut-off voltage is reached.

> Also, Eneloops are not the "best" batteries available in terms of sheer capacity (They are about 2100mAh, no?). Their advantage is that they keep their charge for months without self-discharging.

My RCR-V3s power holding ability is just amazing. Mine have been left unused for almost one year and they are still almost full after one year!

> I think a more meaningful test should be to simply use the camera intensively with Eneloop, normal NiMH 2700mAh, and the other types you have, until they get depleted, and see how many shots they provided. Do it many times and then we'll have meaningful and useful statistics about K-m's battery usage.

I won't test it further as my cameras are for me to shoot but not for testing! ;-)

> The nice thing about it is that this way you can actually combine photography with measurebation! It could be fun! ;-)

Well, the main purpose of my measurbations is all to help to use the camera better and/or (to try) to tackle in-born problems and see if there are some workarounds! :))

RiceHigh said...

> Manu said...

> The real issue is the accuracy of the battery meter. It's simply not good and it's normal: there is no real way to detect the remaining capacity. All you can test is the voltage.

Not really. See my response to Noam above.

> I get the same problem as you have on the K-7 (battery grip stuffed with Eneloop) after power hungry operations like a burst or using liveview/video recording, the indicator will often lose 1 or 2 bars. But the curious thing is that if I go to the menu to choose the battery and don't do anything but just display the menu, the battery indicator get back the bars it just lost(!).

I think it is just a K-7 issue then. My 5D never has shown similar problem.

> The normal NiMh 2700mAh are just garbage IMHO, the Eneloop while being only 2000-2100 work better, longer and don't lose their voltage as fast.

Yes.

> I wouldn't use CRV on the K-m. If Pentax removed that option there must be a reason, no?

Yes, the reason is there are non-regulated RCR-V3 outthere which burnt the Pentax cameras.

Well, I now just use one RCR-V3 plus two Eneloops, which perfectly makes up to an initial total voltage of 6.0V (and there are still much margin for them to drop to the minimum working voltage of 4.8 to 5.0V).

> On the K-m I use exclusively the Eneloops and I've been very pleased by the longevity and performance.

The camera will work unstable and much slower after the first 100 shots (if they are to be taken within a shorter period).

> The fact the K-m use AAs is a strong point for me, I'm not against Li-On proprietary batteries but they have their disadvantages too:
- Another one more charger (you can have your walls filled with chargers as you have a cell phone, an iPod, a camera, etc...

Yes.

> - A backup battery is costly

No. For what I spent on trying different NiMHs and chargers and finally the RCR-V3s and charger costed me much more over years when I used the *ist D, DS and K100D!

> - difficult to find while travelling

Repeated point.

> - How to find them in 10 years after the manufacturer stopped producing them?

The problem is WILL you still use your current DC or DSLR after ten years??

Borislaff Hristoff said...

Hi there,
I am using k200d with the original battery grip and with whatever batteries i try it dies after a few(20-100) shots. I tested a few batteries with a multimeter and here are the results:

batteries that are said to be depleted are:

4 sanyo eneloops - each has 1.3-1.33 volts(tested)
4 Lithium energizers - each has 1.49V, but the camera says depleted and shuts down.

When I connect the grip it is even worse - with 8 Energizer lithums (AA, new) it makes about 20 shots and dies. As you can imagine with Ni-MHs it is even worse. I tried 3 different chargers - 1 sanyo fast charger for 15/30 mins quick charge, 1 sanyo quick charger for 1h and 15 minuties and 1 unknown slow charger for 24 hours - NO difference at all... I am desperate - whenever I take the camera with me it dies after a few minutes. Is it the batteries or is it the charger, or should i try CR-V3s?

Borislaff Hristoff said...

And my fast charger stops charging the batteries after 1 or two minutes because it has a processor that knows when the charge is completed, but the camera says "depleted"again ...

RiceHigh said...

It's the camera. The Eneloop and Energizer L91 should work, although the camera will soon become slower with the Eneloop (and with half-depleted warning on and off for longer, too). But I have never encountered your described full batteries but full depleted and shut off with the camera, neither with my K100D nor my new K-m.

Anonymous said...

I wish I could find the original link ... but when the K10D was announced, the Pentax engineers specifically stated that Lithium batteries were required to provide a strong and stable flow for AF to the lenses - and that's why they moved to Lithium.

As usual, the base was reluctant to buy into that; preferring to stick with older battery tech. I have to think that part of the Pentax slow-AF issue is due to people not moving to Lithium on models where it was offered.

When you add in the need for power for a larger sensor, LV, focus motors, and S/S, I consider the PK comparatively an energy hog. Power gets more flaky with higher heat loads. With video mode, the requirements only increase.

Just glancing at the Canon 500D, here are the choices:

Lithium-Ion LP-E5 rechargeable battery (7.4 V, 1050 mAh)

Optional ACK-E5 AC adapter kit / car battery charger CBC-E5

Also, the battery grip, where someone could use 6 AA's:

http://www.the-digital-picture.com/Reviews/Canon-BG-E5-Battery-Grip-Review.aspx

Here's a comparison for GPS use:

http://forums.groundspeak.com/GC/index.php?showtopic=160997

Powerex 2700 straight out of the charger - lasted 22 hours, 13 Minutes

Powerex 2700 after sitting on the shelf for a month - lasted 18 hours, 15 minutes

eneloop 2000 straight out of the charger - lasted 17 hours, 53 minutes

eneloop 2000 after sitting on the shelf for a month - lasted 15 hours, 7 minutes

Manu said...

I don't care about the Rebel and the GPS use is interesting but is it really relevant? Cameras, especially now with Liveview and video, are much more power hungry.

I may have very good Eneloop but I don't recall having any issues with the K200D (I had it only for a few weeks but used in a rather cold Canadian winter) and the K-m. I certainly get much more than 100 shots.

Anonymous said...

Re: but I don't recall having any issues with the K200D (I had it only for a few weeks but used in a rather cold Canadian winter) and the K-m.

------------------

Do those bodies have Live View?

These anecdotes do not displace science. For high and continuous current draw, you want Lithium. Pentax itself designed the K10D for it.

To me, it's another case where ANY maker's legacy base asks for retention of old tech, keeping the maker distracted from moving forward.

Look at the GM bankruptcy - TWO companies are being created. One gets to carry the old baggage, and one gets to be called General Motors. It may be too late to make this work due to dealer closings and perceived warranty issues; but the choice was GM and its supplier base sliding into the abyss. Lear, the world's second-largest auto-seat maker, already went Chapter 11. In the domestic auto-maker industry, they had capacity far in excess of market share.

Hoya closed the Japanese plants, and production is now in the Philippines and Vietnam. How come old Pentax did not do this?

In technology, you move forward, or perish. Nikon and Canon dealt with their mount issues years ago; and in effect said "Tough!" to some portion of their user base that was not spending, anyway.

I think that Pentax is past the point where they have options.

Manu said...

"Do those bodies have Live View?"

Do the bodies who have Live View use AAs?

The rest of your post is so totally irrelevant in the typical PhilBarton style... Lots of blah-blah as if you actually knew something but you're not. You're probably not even using a Pentax DSLR !!

Did some of you actually read the K2000 manual? page 39 there is a memo that explains that burst mode can make the battery low indicator appearing. Just turn off and on the camera again in that case.

Pentax know how to use Li-On, they just choose to use AAs in their lower end bodies. I like it and also use AA with my K-7 battery grip.

Anonymous said...

RE: The rest of your post is so totally irrelevant ...

=============

As usual, you're a fanbot stuck for an actual response.

You seem to lack a grasp of business, so I guess that's the best you've got.

I don't have a Pentax DSLR, because I never found what they were offering worth my time. One example is the lack of X-sync until the K20D. They've spent over 5 years doing minor increments to what came before using purchased components, and some out-of-date SDM that cannot even work as quickly as their prior lenses.

I kept hoping that they'd actually change; but the need for movie mode, and decisions about sealing in heat, have given them a problem - as well as their own announced sensor upgrade, and asking reviewers not to publish.

They keep using AA's because the user base keeps asking for 10-year-old tech. Tending to your legacy base is how a company goes into decline, because they're not attracting new buyers with money to spend. With the lens price increase, they are out of ammo.

Check the various DPREVIEW threads where people are buying K20D rather than the K-7. Whatever I might have to say, those posters and their PK lenses are your problem. That's the group that should be running after the K-7.

I own my own thermometer - I don't need the K-7.

Go plug yourself in, Pentax Roomba - your battery appears low.

Anonymous said...

Amazon DSLR sales:

K-7 at #31 (was #9 the first day)

K20D at #19 with DA 18-55.

K2000 with 2 lenses at #53.

Tough to win when you're your own competition. Same 5 dealers for K-7 all sticking to list price.

No news in Google since 7/16.

If you get a pair of Pentax binoculars, perhaps you can spot it better.

Anonymous said...

Re: liveview stuff and batteries: Ken Rockwell on July 24 updates points to a potential problem with movie mode and liveview in DSLRS: more risk of dirt on the sensor due to the mirror exposing it for longer periods.

As to the anti-Pentax views, why bother to preach to the converted? Sounds more like a sneer campaign.

I use Pentax and Nikon dslrs for different purposes. I get plenty of shots (more than 400) with mixed flash/non-flash) with AAs.

As for all the lens focus stuff, my Pentax compares more than favourably with my Nikon dslr.

Michael said...

From my Eneloops (with are gone through some cycles already, so they reached their full capacity) I got around 800 shots from my last shooting, before getting the batterlow warning, so I changed them to be safe. I think some 10 shots still slept in them, but I had to go for a hike, so I changed them.
In ten years, when all the LiIon Batterie-Sets bought today have gone to heaven and no exchange cells are availiable, due to Pentax ceasing to produce them, I go to my local dealer to get some NiMH-AAs and my K-m will still be running. :-)

Anonymous said...

RE:

In ten years, when all the LiIon Batterie-Sets bought today have gone to heaven and no exchange cells are availiable, due to Pentax ceasing to produce them, I go to my local dealer to get some NiMH-AAs and my K-m will still be running. :-)

===================

But Pentax itself will be history, and Canon and Nikon will continue to use Lithiums (or whatever else comes along) due to the power requirements of today's advanced cameras.

Using Pentax as a model of technology is not what I'd choose.

The planned lifespan of a DSLR is a few years for prosumer models. With low usage and simple models, they'll last longer - but the buying public will have moved on. These are not Spotmatics, and repair costs will become a factor, since DSLR prices will have dropped by then.

Anonymous said...

Re : "But Pentax will be history..."

MMM... I remember people saying that about Apple Computers many times in the past. In 1945 several car companies were offered the VW Beetle design and factory. For free. They laughed and now VW has taken over some of them. Like Rolls Royce.
In 1965 I saw a panel of eminent experts predict 1980. The only thing that came true was the most unlikely prediction of all.
Who knows, Canon and Nikon could be taken over by a Chinese company.
A prediction of my own: DSLRS with video will eventually be history. I've just read Ken Rockwell's views on the matter after a previous post. I don't think slr mirrors can do much more than briefly flip before eventually developing alignment problems. And who wants dirt on their movies?

Manu said...

“As usual, you're a fanbot stuck for an actual response.”

Yes of course, labelling is always a very strong argument.

“I don't have a Pentax DSLR, because I never found what they were offering worth my time.

They don’t worth your time so what the hell are you doing here, troll?

“They keep using AA's because the user base keeps asking for 10-year-old tech. Tending to your legacy base is how a company goes into decline, because they're not attracting new buyers with money to spend. With the lens price increase, they are out of ammo.”

That’s ridiculous, I don’t know exactly why they keep using AA, but it’s certainly not to please the “user base” or because they wouldn’t have the technology (laughable). These entry-level are often targeted at new users, the “base” is more interested in the K20D/K-7 lines.

The lens price increase affects everybody, not just Pentax; we’ll have to wait a little bit before drawing any conclusion about that.

“Check the various DPREVIEW threads where people are buying K20D rather than the K-7. Whatever I might have to say, those posters and their PK lenses are your problem. That's the group that should be running after the K-7.”

It’s the sensible thing to do if you don’t yet have many lenses. Pentax users seem to be smart. The Online Photographer was going to put the K20D at #2 in their annual list of best DSLR just for that reason: the K20D at the current prices is a huge bargain.

“I own my own thermometer - I don't need the K-7.”

Wow, an attempt at humour, I’m impressed :-)

Anonymous said...

Re some negative anti-Pentax posts, including Ricehigh's occasional outburst of frustration:

even if Pentax is gone in 10 years, which is a proposition I wouldn't bet the farm on, I won't change to anything else come hell or high water.
Why? Because I like Pentax: good to use, great value and an aversion to built-in plastic lenses and obsolescence.

Get it, preacherman?

Hate_Idiots said...

Shit ... this guy RICE Something, does not like sex !!!
I have told him a number of times to start writing about SEX and nothing happens !!!!

Hey RICE Something just try having sex once. Its nice, trust me, asshole.

Anonymous said...

Rice, are you normal human?
I've talked with Pentax service and they told me that RCR-V3 could burn down K100D, K200D, K-m. There are incidents with such link "new K camera with AA batteries + RCR-V3 (CR-V3)" шт various countries.

My K200D + battery grip could make with Energizer Lithium approx. 1500-2000 shots.

RiceHigh said...

So, you should really go read thoroughly my articles then you'll know the truths.

Anonymous said...

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toshiba pa3399u-2brs said...

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